taxonomía-jun2026

Redescripción de Stagmomantis hebardi (Mantodea: Mantidae), con la descripción de la hembra

Aarón Emilio Vásquez-Quintero a, Iker Cubillos-Macías b, Erick Omar Martínez-Luque c, Jovana M. Jasso-Martínez b y Fernando Varela-Hernández a, *

a Universidad Autónoma del Estado de Morelos, Escuela de Estudios Superiores del Jicarero, Laboratorio de Sistemática Molecular, Carretera Galeana-Tequesquitengo s/n, Col. El Jicarero, 62909 Jojutla, Morelos, Mexico
b Universidad Nacional Autónoma de México, Instituto de Biología, Colección Nacional de Insectos, Tercer Circuito Exterior s/n, Cd. Universitaria, Copilco El Alto, Coyoacán, Apartado postal 70-233, 04510 Mexico City, Mexico
c Universidad Autónoma de Querétaro, Facultad de Ciencias Naturales, Av. de las Ciencias s/n, Juriquilla, 76230 Querétaro, Querétaro, Mexico

*Corresponding author: fernando.varela@uaem.mx (F. Varela-Hernández)

Received: 02 September 2025; accepted: 08 December 2025

Abstract

The genus Stagmomantis Saussure, 1869 comprises a group of New World mantids whose taxonomic delimitation and composition have been challenging due to complex morphological variation. Stagmomantis hebardi Rehn, 1935, a species distributed in the Neotropical region and the Mexican Transition Zone, was originally described based on both a female and a male specimen. However, the female was subsequently recognized as belonging to a different species within the subgenus Auromantis. In this study, we provide the redescription of the male and the description of the female of S. hebardi. Descriptions are based on external morphology and both sexes internal genitalia characters. The conspecificity of the male and female is supported by molecular evidence provided in previous studies and further validated by biological observations from captive rearing. The corkscrew-like pda (posterior process of the ventral phallomere) in the male genitalia and the lobe-like structure between the fifth and sixth tergites in the female abdomen are diagnostic characters that distinguish this species from others of the genus Stagmomantis.

Keywords: External morphology; Internal genitalia; Mantids; Taxonomic description

Resumen

El género Stagmomantis Saussure, 1869 es un grupo de mantis del Nuevo Mundo cuya delimitación y composición han sido desafiantes debido a su compleja variación morfológica. Stagmomantis hebardi Rehn, 1935, una especie distribuida en la región Neotropical y la Zona de Transición Mexicana, fue descrita originalmente con base en un macho y una hembra. Más tarde, se reconoció que la hembra pertenecía a una especie diferente del subgénero Auromantis. En este estudio, proporcionamos la redescripción del macho y la descripción de la hembra de S. hebardi. Ambas descripciones se basan en caracteres de morfología externa y de la genitalia de ambos sexos. La asociación específica entre el macho y la hembra está respaldada por análisis moleculares previos y validada por observación directa en cautiverio. El pda (proceso posterior del falómero ventral) en forma de sacacorchos en la genitalia del macho y la estructura en forma de lóbulo entre los terguitos quinto y sexto en el abdomen de la hembra son caracteres clave para separar a esta especie de otras del género Stagmomantis.

Palabras clave: Morfología externa; Genitalia interna; Mantis; Descripción taxonómica

Introduction

The order Mantodea (praying mantises) comprises about 2,500 species worldwide, distributed in 16 superfamilies, 29 families, 60 subfamilies, and 436 genera (Ehrmann, 2002; Otte & Spearman, 2005; Schwarz & Roy, 2019). Mantidae Latreille, 1802 is the most species-rich family, containing approximately half of the described species (Patel & Singh, 2016; Svenson & Whiting, 2004, 2009); however, the limits and phylogenetic relationships within Mantidae remain unclear. Several groups previously defined based on morphological data were later recovered as non-monophyletic by analyses using mitochondrial and nuclear genes (Svenson & Whiting, 2004, 2009), as well as mitochondrial genomes (Wang et al., 2022; Xu et al., 2021).

Stagmomantis Saussure, 1869 is a New World genus belonging to the subfamily Stagmomantinae Giglio-Tos, 1919. It is one of the most species-rich genera within Mantidae, with 25 recognized species (Anderson, 2025). Species delimitation within Stagmomantis has been challenging due to significant morphological variation among its members, rendering the number of valid species debatable (Agudelo-Rondón et al., 2007; Anderson, 2020a, b, 2021; Ehrmann, 2002; Maxwell, 2014; Otte & Spearman, 2005; Terra, 1995). For instance, Maxwell (2014) did not recognize S. conspurcata Serville, 1869 as a valid species, treating it as a synonym of S. carolina (Johansson, 1763). Later, Anderson (2020b) revalidated S. conspurcata, arguing that sufficient morphological differences —such as body size and male hindwing coloration— justified its recognition as a distinct species. This case exemplifies the taxonomic instability present within Stagmomantis, which has important implications, such as constant changes in the reported geographic distribution patterns of its species.

In 1935, Rehn described Stagmomantis hebardi —named after the American entomologist Morgan Hebard— based on a female and a male specimen from Sinaloa, Mexico. Hebard (1923) had previously identified these specimens as S. limbata Hahn, 1835 and S. tolteca Saussure, 1861, respectively. In his description, Rehn included images of the dorsal habitus of both the female and male, as well as an illustration of the male’s internal genitalia. The taxonomic status of S. hebardi, based on the male-female association established by Rehn, has remained unchallenged for decades.

Recently, a molecular analysis grouped together a female and a male specimen previously identified as S. carolina (Varela-Hernández et al., 2022). In addition to the molecular data, that study included high-resolution images of the dorsal habitus. Subsequent comparison of those specimens with the descriptions and illustrations in Rehn (1935) revealed that the male assigned to S. carolina corresponded to S. hebardi. Crucially, the morphological traits of the female described as S. hebardi by Rehn (1935) did not match those of the female specimen molecularly associated with the male in Varela-Hernández et al. (2022).

Based on this evidence, we consider that Rehn (1935) erroneously associated the sexes of S. hebardi, establishing a heterospecific type series. Consequently, the main objectives of this study are to correctly associate both sexes of S. hebardi, to redescribe the male, and to formally describe the female of S. hebardi (Rehn, 1935). This work is supported by the aforementioned molecular evidence and is based on external morphology as well as a comprehensive analysis of male and female genitalia.

Materials and methods

A total of 48 pinned specimens identified as Stagmomantis hebardi were examined (29 males and 15 females, see “Taxonomic summary”). These specimens are deposited at the Colección Nacional de Insectos, Instituto de Biología, Universidad Nacional Autónoma de México (CNIN-IBUNAM) and the Colección Entomológica de la Universidad Autónoma del Estado de Morelos, México (CEUAEM-MAN). Additionally, we examined high-resolution images of the holotype (Fig. 1) and allotype (Fig. 2) deposited at the Academy of Natural Sciences of Philadelphia (ANSP), USA.

Observations and measurements were conducted using an Olympus SZ stereomicroscope. Specimens identification at genus and species level followed the keys and descriptions provided by Rehn (1935), Agudelo-Rondón and Chica (2002), Maxwell (2014), and Anderson (2021). Specimens of both sexes were photographed from multiple angles using a Canon EOS Rebel T5 digital camera equipped with an EF 100 mm f/2.8 Macro USM lens. Camera control was managed via EOS Utility software; images were subsequently stacked and edited using Zerene Stacker and Photoshop CC 2019.

Terminalia of both sexes were softened in hot water (80-100 °C) for 15-20 min, following the protocol of Ferraz et al. (2023). Genitalia were then cleared in a 10% KOH solution at 40 °C for 20-30 min (Brannoch et al., 2017). The extraction of female genitalia followed the method described by Rodrigues and Cancello (2016). Cleared genitalia were rinsed twice in distilled water and stored in 70% ethanol. Remaining soft tissue was removed, and structures were photographed suspended in antibacterial gel to maintain their position (Su, 2016). Abbreviations for all measurements and genitalic structures are provided in Table 1.

To visualize the geographical distribution of the examined specimens, a map was generated using ArcGIS software, utilizing the State Geostatistical Framework, scale 1:250,000 (INEGI, 2024).

Description

Stagmomantis hebardi Rehn, 1935

Diagnosis. Male: distinguished by the corkscrew-like posterior process of the ventral phallomere (pda) (Fig. 3). Female: prosternum (inter-coxal area) blackish; anterior coxae armed with 3-6 blackish spines; presence of a protrusible lobe-like structure located between abdominal tergites 5 and 6 (Fig. 4).

Category	Abbreviation	Meaning
Morphological	ACL	Anterior coxae length
Morphological	AFL	Anterior femur length
Morphological	AFW	Anterior femur width
Morphological	ATL	Anterior tibia length
Morphological	AvS	Anteroventral spines
Morphological	DS	Discoidal spines
Morphological	FwL	Forewing length
Morphological	HH	Head height
Morphological	HW	Head width
Morphological	HwL	Hindwing length
Morphological	ML	Metazone length
Morphological	MFL	Metafemur length
Morphological	MTL	Metatibia length
Morphological	MsFL	Mesofemur length
Morphological	MsTL	Mesotibia length
Morphological	PL	Pronotum length
Morphological	PrL	Prozone length
Morphological	PvS	Posteroventral spines
Morphological	PW	Pronotum width
Morphological	TL	Total length
Male genitalia	aafa	Anterior lobe of phalloid apophysis (left phallomere)
Male genitalia	an	Anterior extension of sclerite R3 (right phallomere)
Male genitalia	bm	Dextral extension (right phallomere)
Male genitalia	fda	Main posterior lobe (right phallomere)
Male genitalia	L4A	Sclerite extending over the ventral wall (ventral phallomere)
Male genitalia	L4B	Sclerite extending over the dorsal wall (left phallomere)
Male genitalia	loa	Posteromesal (left phallomere)
Male genitalia	paa	Posterior process (left phallomere)
Male genitalia	pafa	Posterior lobe of phalloid apophysis (left phallomere)
Male genitalia	pda	Posterior process (ventral phallomere)
Male genitalia	pia	Process posterolateral to pva (right phallomere)
Male genitalia	pva	Process anteromesal to pia (right phallomere)
Male genitalia	R3	Anteriorly extending sclerite (right phallomere)
Male genitalia	ssp	Secondary spine
Female genitalia	agsl	Accessory gland supporting lobe
Female genitalia	CG8	Caudogyne
Female genitalia	CX8	Coxa 8
Female genitalia	cxdl	Dorsolateral coxal lobelet
Female genitalia	cxvl	Ventrolateral coxal lobelet
Female genitalia	gl9	Gonoplac 9
Female genitalia	gp8	Gonapophysis 8
Female genitalia	gp9	Gonapophysis 9
Female genitalia	gpal8	Apical lobe of gonapophysis 8
Female genitalia	gpmo8	Medial outgrowth of gonapophysis 8
Female genitalia	gptm9	Medial tine of gonapophysis 9
Female genitalia	rh	Rhachis
Female genitalia	spb	Spermathecal bulge
Female genitalia	vf7	Ventral segmental fold 7
Female genitalia	VS7	Vestibular sclerite 7

Identification. Males: antennae longer than pronotum. Tubercle present between antennifer and compound eyes. Wings longer than abdomen; fore- and hindwings hyaline; costal area of forewings opaque with brown spots. Genitalia with the posterior process of ventral phallomere (pda) corkscrew-shaped. Females: abdominal tergites 4-6 dorsoventrally flattened; protrusible lobe-like structure present between tergites 5 and 6. Supragenital plate wider than long with well-developed longitudinal medial keel. Forewings opaque, greenish or brownish, with brown spots; hindwings opaque, anteriorly yellowish with brown spots near posterior margin, or yellowish with colorless spots posteriorly. Both sexes: ocellar tubercles absent; ocelli flush with surface of frons. Lower frons smooth, wider than long. Pronotum long and slender; lateral margins denticulate; dorsal surface smooth. Forecoxae approximately 3/4 the length of pronotum; anterior and posterior margins denticulate; forecoxal lobes convergent. Hearing organ of DK type.

Male (Fig. 5). Measurements (Table 2). Head: head capsule (Fig. 6a) with oval eyes; juxtaocular bulges undeveloped; ocellar tubercles undeveloped. Anterior margin of vertex straight, depressed near parietal sulcus. Ocelli larger than in females. A small tubercle present between antennifer and compound eye. Antennae filiform, longer than pronotum, reaching anterior portion of the mesothorax; pedicel nearly as long as scape. Frons wider than long, with an M-shaped depression in the middle of the transverse carina. Thorax: pronotum, supracoxal dilation slightly pronounced; supracoxal groove well-marked. Lateral margins of prozone denticulate; lateral margins of metazone denticulate, denticles decreasing in size posteriorly. In ventral view, inter-coxal area dark-colored. Legs: forelegs, spination formula: F = 4DS/12-15AvS/4PvS; T = 9-14AvS/9-11PsV. Forecoxae armed with 3-5 blunt, often blackish spines, small denticles interspersed between them; coxal lobes convergent (Fig. 6b). Forefemur relatively long, slender; femoral brush located at the level of last 3 posteroventral spines; tibial spur groove located at approximately the middle of femur; first discoidal spine smaller than the others; third discoidal spine longer than the others; blackish spot present at the level of first anteroventral spine (AvS). Foretarsus: distal portion of each segment darkened (Fig. 6c, d). Wings: slightly surpassing tip of abdomen. Forewings: hyaline, with scattered brown spots in discoidal area; stigma covered by dark brown patch; anterior margin wide at base, narrowing posteriorly; apex rounded. Hindwings: hyaline with a dark patch at apex; main central longitudinal veins feature a series of spotted brownish lines running along posterior margin to about half the distance to anterior margin (Fig. 5). Abdomen: slender, cylindrical. Subgenital plate longer than wide. Supragenital plate wider than long; apex rounded, with marked longitudinal medial keel. Cerci elongate; cercomeres cylindrical, subequal in length; distal cercomere smaller, conical, rounded at apex.

Genitalia: left phallomere, sclerite L4B almost rectangular, longer than wide, with left margin projected anteriorly (Fig. 7a). Anterior lobe of phalloid apophysis (aafa) linguiform, sometimes oval, distally dentate. Posterior lobe of phalloid apophysis (pafa) elongated, apically rounded, dentate, bearing 3-6 ventral denticles. Posteromesal lobe (loa) oval, bearing short setae. Posterior process (paa) robust, sometimes slender. Right phallomere: triangular (Fig. 7b); posterior apex rounded with short setae. Dextral extension (bm) thick, slightly elongate; anterior extension of sclerite R3 (an) elongate, slender. Process anteromesal to pia (pva) short, thick, smooth with rounded apex; process posterolateral to pva (pia) short, smooth. Ventral phallomere: sclerite L4A oval (Fig. 7c, d). Secondary spine (ssp) well-sclerotized, triangular. Posterior process (pda) corkscrew-shaped, twisted left or right, with apex angled to slightly flattened.

Spec. ID	TL	PL	PrL	ML	PW	HH	HW	ACL	AFL	AFW	ATL	FwL	HwL	MsFL	MsTL	MFL	MTL
CEUAEM-MAN-140	51.0	16.5	3.5	13.0	2.5	4.0	5.0	8.5	9.5	1.0	6.0	33.0	30.5	10.0	9.0	13.0	13.0
CEUAEM-MAN-135	51.0	15.5	3.0	14.0	3.0	4.0	5.0	7.5	10.0	1.0	6.0	32.0	31.0	10.0	9.0	13.0	13.0
CEUAEM-MAN-013	55.0	18.0	4.0	14.5	3.0	4.0	5.5	9.0	11.0	1.5	7.0	35.0	34.0	11.0	10.0	13.0	13.0
CEUAEM-MAN-021	45.5	15.5	3.0	12.0	2.5	3.5	5.0	7.5	9.5	1.0	5.0	31.0	27.0	10.0	9.0	11.0	12.0
CEUAEM-MAN-015	47.0	16.5	4.0	12.5	2.5	4.0	5.0	8.0	10.0	1.5	6.0	34.0	31.5	10.0	9.0	13.0	12.0
CEUAEM-MAN-014	45.0	18.0	3.5	13.5	3.0	3.5	5.5	8.5	10.5	1.5	6.0	34.0	31.0	10.5	9.5	13.0	13.0
IBUNAM: CNIN: MA645	64.0	21.5	3.5	18.0	3.5	–	–	–	12.0	–	6.0	–	–	–	–	15.0	14.5
IBUNAM: CNIN: MA810	55.5	19.0	3.0	16.0	3.0	–	–	–	11.0	–	5.0	–	–	–	–	14.0	15.0
IBUNAM: CNIN: MA946	54.0	16.0	3.0	13.0	3.5	–	–	–	10.0	–	4.5	–	–	–	–	–	–

Female (Fig. 8). Measurements (Table 3). Head: head capsule with oval eyes; juxtaocular bulges absent; ocellar tubercles absent; ocelli smaller than in males. Anterior margin of vertex straight; vertex slightly depressed near parietal sulcus. Antennae filiform; scape almost twice as long as pedicel. Frons wider than long in frontal view, with M-shaped depression in the middle of transverse carina (Fig. 9a). Thorax: pronotum, supracoxal dilation slightly pronounced; supracoxal groove well-marked. Lateral margins of prozone denticulate; lateral margins of metazone denticulate, becoming smooth distally; medial keel of pronotum well-developed. In ventral view, inter-coxal area brownish. Legs: forelegs, spination formula: F = 4DS/14-16AvS/4PvS; T = 12-14AvS/8-10PvS. Forecoxae (Fig. 9b) armed with 3-6 apically blunt spines, often brownish, denticles interspersed among them; forecoxal lobes convergent. Forefemur relatively long, slender; femoral brush located at the level of last 3 posteroventral spines; tibial spur groove located at approximately half the length of femur; first discoidal spine smaller than the others; third discoidal spine longer than the others; with blackish spot at the level of first anteroventral spine (AvS). Foretarsus: distal portion of each segment blackish (Fig. 9c, d). Wings (fig. 10a-c): reaching approximately 3/4 the length of abdomen. Forewings: anterior margin wide at base, narrowing distally; color variable, ranging from brown to light hues; stigma darker than rest of wing. Hindwings fully colored; color variable, ranging from yellowish at base to middle area, with dark spots distally, to yellowish with hyaline spot; apex of hindwing yellowish with greenish portions. Abdomen: dorsoventrally flattened, reaching maximum width between 4th and 6th tergites, with prominent, protrusible lobe-like structure between 5th and 6th tergites. Supragenital plate wider than long, rounded at the apex, with a marked longitudinal medial keel. Cerci elongate; cercomeres cylindrical, subequal in length; distal cercomere smaller, conical, apically rounded.

Genitalia (Fig. 11): gonoplacs (gl9), simple, elongate, apically rounded, bearing short setae throughout, with longer setae apically. Gonapophysis: gonapophysis 9 (gp9) membranous, elongate, shorter than gl9. Gonapophysis 8 (gp8) elongate, bearing short setae; in lateral view, distinct furrow near ventral margin; lateral margins sinuous depressed near base of apical lobe (gpal8). Apical lobe of gonapophysis 8 (gpal8) glove-shaped; dorsal portion laterally compressed, distally rounded; ventral portion short, elongate; surface covered with short setae, longer setae on inner surface. Medial outgrowth of gonapophysis 8 (gpmo8) well-developed. Coxa 8 (CX8): acuminate, broad, rounded at base, tapering distally; divided into dorsal and ventral regions by a marked depression, a prominent keel extending through middle of depression. Dorsal region of CX8 elongate lateral wider, more rounded than dorsal region. Caudogyne (CG8) weakly sclerotized; dorsal margin rounded, sinuous; ventral margin depressed at the middle (M-shaped). Spermathecal bulge (spb) well-sclerotized. Accessory gland supporting lobe (agsl) smooth, weakly sclerotized. Ventral segmental fold 7 (vf7) membranous, rounded, with sinuous margins. Vestibular sclerite (VS7) weakly sclerotized, rhomboidal in shape, with ventro-medial corner rounded.

Spec. ID	TL	PL	PrL	ML	PW	HH	HW	ACL	AFL	AFW	ATL	FwL	HwL	MsTL	MFL	MTL
CEUAEM-MAN-139	52.0	20.0	4.5	15.5	4.0	4.5	7.0	10.0	13.0	1.5	8.0	19.5	17.0	12.0	10.5	15.5
CEUAEM-MAN-129	48.0	18.0	3.5	15.0	3.0	4.2	6.0	9.0	11.5	1.5	7.0	19.0	17.0	11.0	10.0	15.0
CEUAEM-MAN-019	48.0	20.0	4.5	15.5	3.8	4.5	7.0	9.5	12.0	2.0	8.0	–	–	12	11	16.0
CEUAEM-MAN-018	49.0	21.0	4.5	17.0	4.0	4.5	6.5	10.0	13.0	2.0	8.0	21.0	–	12	11	15.5
CEUAEM-MAN-017	51.0	20.0	4.5	15.5	4.0	5.0	7.0	10.0	13.0	2.0	8.0	–	17.0	12.0	11.0	16.0
CEUAEM-MAN-138	53.0	20.0	4.5	16.0	4.0	5.0	7.0	10.5	13.0	2.0	8.0	22.0	18.0	12.0	11.5	16.0
CEUAEM-MAN-109	48.0	19.5	4.0	15.5	4.0	4.0	7.0	9.5	12.5	2.0	6.5	20.0	16.0	12.0	11.0	15.0
IBUNAM: CNIN: MA1560	55.0	23.0	5.0	18.0	4.0	–	–	–	13.0	–	6.5	–	–	–	–	17.0
IBUNAM: CNIN: MA946	54.0	16.0	3.0	13.0	3.5	–	–	–	10.0	–	7.0	–	–	–	–	17.5

Taxonomic summary

Holotype: 1 ♀, Mexico. Sinaloa: Venvidio, 2-6.VIII.1918, type # 8988 (ANSP). Allotype: 1 ♀, Sinaloa: Los Mochis, 25.XII.1918 (ANSP). Additional material examined: Mexico. Estado de México: 1 ♂, Nepantla, Finca Badoni, 18°59’0.8” N, 98°50’44.9” W, 2,020 m asl, 05.X.2023 (CEUAEM-MAN-135); 1 ♀, Malinalco, Chalma, 118°55’56.3” N, 99°26’11” W, 29.XI.1980 (IBUNAM: CNIN: MA909). Guerrero: 10 specimens (5 ♂, 5 ♀). Five ♂: Acahuizotla, 17°28’8.9” N, 99°25’10.3” W, 18.XI.1983 (IBUNAM: CNIN: MA644, MA645); Iguala, Km 3 desv. a Tepecoacuilco, 18°17’32” N, 99°28’58” W, 14.X.2006 (IBUNAM: CNIN: MA724); Iguala, Tuxpan, 2 km a Microondas, 18°23’34” N, 99°28’27” W, 14.X.2006 (IBUNAM: CNIN: MA813); Tecpan, La Laguna, Km 15 San Luis, 17°13’14.9” N, 100°37’9.3” W, 1,425 m asl, 20.VII.2005 (IBUNAM: CNIN: MA816). Five ♀: Atenango del Río, Km 36 Huitzuco-Atenango, 18°8’32” N, 99°7’49” W, 200 m asl, 14.X.2006 (IBUNAM: CNIN: MA823); Guerrero, 22.IX.2022 (CEUAEM-MAN-159, CEUAEM-MAN-160); Guerrero, 2024 (CEUAEM-MAN-161, CEUAEM-MAN-162). Jalisco: 13 specimens (11 ♂, 2 ♀). Eleven ♂: La Huerta, Estación de Biología Chamela (UNAM), 19°29’55.2” N, 105°2’39.5” W, 01.VIII.1981 (IBUNAM: CNIN: MA426); 10.V.1980 (IBUNAM: CNIN: MA802, MA804); 24.V.1980 (IBUNAM: CNIN: MA803); 10.VIII.1981 (IBUNAM: CNIN: MA805-MA810); 01.IV.1981 (IBUNAM: CNIN: MA811). Two ♀: La Huerta, Estación de Biología Chamela (UNAM), 19°29’55.2” N, 105°2’39.5” W, 14.X.1990 (IBUNAM: CNIN: MA723); 08.VIII.1975 (IBUNAM: CNIN: MA1560). Morelos: 23 specimens (12 ♂, 11 ♀). 12 ♂: Jojutla, EESJ, 18°36’49.8” N, 99°13’50.2” W, 957 m asl: 08.III.2022 (CEUAEM-MAN-013); 07.X.2018 (CEUAEM-MAN-014); 21.XI.2018 (CEUAEM-MAN-015); 20.XI.2019 (CEUAEM-MAN-021); Jojutla, 18°36’41.6” N, 99°10’44.7” W, 894 m asl, 21.X.2023 (CEUAEM-MAN-140); Morelos, 18°39’3.9” N, 99°2’20.5” W, 16.XI.1972 (IBUNAM: CNIN: MA519, MA520); Tepalcingo, Sierra de Huautla, 18°32’31.3” N, 98°56’9.4” W, 12.VI.2016 (IBUNAM: CNIN: MA943-MA946). Eleven ♀: Zacatepec, Galeana, 18°38’24.1” N, 99°12’39.6” W, 934 m asl, 22.IX.2019 (CEUAEM-MAN-017); Jojutla, EESJ, 18°36’49.8” N, 99°13’50.2” W, 957 m asl: 28.XI.2019 (CEUAEM-MAN-018); 22.XI.2019 (CEUAEM-MAN-019); 25.IX.2020 (CEUAEM-MAN-109); 13.XI.2020 (CEUAEM-MAN-110); 04.X.2023 (CEUAEM-MAN-129); Tehuixtla, 18°33’16.8” N, 99°16’12.8” W, 26.XII.2019 (CEUAEM-MAN-072); Yautepec, 18°53’12.8” N, 99°3’47.8” W, 1,216 m asl, 17.X.2023 (CEUAEM-MAN-138); Jojutla, 18°36’41.6” N, 99°10’44.7” W, 894 m asl, 27.X.2023 (CEUAEM-MAN-139); Cuautla, 18°48’59.4” N, 98°56’56” W, XI.1954 (IBUNAM: CNIN: MA905); Morelos, 18°39’3.9” N, 99°2’20.5” W, IV.1981 (IBUNAM: CNIN: MA906). Nayarit: 1 ♂, Bahía de Banderas, San Rafael, Arroyo de la Virgen, P. H. Aguamilpa, 20°50’19.5” N, 105°16’44.4” W, 734 m asl, 01.XI.1991 (IBUNAM: CNIN: MA824).

Geographic distribution: Stagmomantis hebardi is distributed in the states of Estado de México, Guerrero, Jalisco, Morelos, Nayarit, and Sinaloa (Fig. 12).

Remarks

Taxonomic delimitation within Stagmomantis based on male morphology has been a subject of study for decades. Notably, Saussure and Zehntner (1894) and Rehn (1935) considered the males of S. carolina and S. tolteca to be indistinguishable, grouping them within the “carolina group,” which currently corresponds to the subgenus Stagmomantis.

Morphological differences between the female originally described by Rehn (1935) and the females analyzed in this study are summarized in Table 4. Key distinctions include: a) the pronotum is proportionately wider in Rehn’s female compared to the slender pronotum in our specimens; b) wing shape and coloration differ significantly; Rehn’s specimen has wider forewings with a small, oval, light-colored stigma lacking a surrounding patch, whereas our specimens exhibit a stigma covered by a dark patch and surrounded by a white area covering nearly the proximal half of the wing; c) the abdomen in Rehn’s female is widely oval, whereas it is subfusiform (widening at the distal segments) in the females observed in this study; and d) the lobe-like structure between the 5th and 6th abdominal tergites, observed in all examined specimens, appears to be a diagnostic feature and a potential autapomorphy for this species.

Rehn (1935)	Present study
Pronotum wide	Pronotum slender
Forewings solid light colored	Forewings with different combinations of colors
Forewing’s stigma not covered by a colored patch	Forewing’s stigma covered by a white and dark patch
Forewings wider	Forewings slender
Abdomen wider almost oval	Abdomen subfusiform
Abdomen without lobe-like structure	Abdomen with lobe-like structure

Although Stagmomantis tolteca and S. hebardi are morphologically similar, significant differences in male genitalia provide reliable diagnostic characters. As noted by Arteaga-Blanco et al. (2016), the posterior process of the ventral phallomere (pda) in S. tolteca is strongly sclerotized, wide at the base, tapering distally into a spine, and directed sinistrally (Fig. 13a, blue). Conversely, in S. hebardi, the pda is corkscrew-shaped, twisted either sinistrally or dextrally (Figs. 1, 5, 13b, blue). Further comparisons revealed differences in other genitalic structures: the aafa in S. tolteca is triangular with an angulate apex (Fig. 13a, yellow), whereas it is rounded in S. hebardi (Figs. 5, 13b, yellow); the ssp in S. tolteca is more developed with a slightly angulate inferior margin (Fig. 13a, purple), compared to the small and triangular ssp in S. hebardi (Figs. 5, 13b, purple); finally, the pafa in S. tolteca is elongate and curved near the middle, with the apex directed inward (Fig. 13a, green), while the pafa of S. hebardi projects laterally, is less curved, and has a more rounded apex (Figs. 5, 13b, green). The paa is morphologically similar in both species (Fig. 13, red). Rehn’s (1935) illustrations of the male genitalia correspond more closely to the pda morphology described in the present study than to that illustrated in Arteaga-Blanco et al. (2016). Thus, the sclerotized structure of the pda serves as a robust diagnostic character to separate both species and supports the identification of our male specimens as S. hebardi, in accordance with Rehn (1935).

A remarkable feature observed in this study is the presence of a lobe-like structure on the female abdomen. While comparable structures are rare in Mantodea, a few instances have been documented. For example, Robinson and Robinson (1979) described a terminal abdominal structure in females of Acanthops falcata Stål, 1877, identifying it as a pheromone-releasing gland. Similarly, Schwarz and Glaw (2021) described a Y-shaped protrusible structure near the abdominal apex of Stenophylla lobivertex Lombardo, 2000, hypothesizing that it represents a pheromone-releasing gland more efficient than simpler structures performing the same function.

The precise function of the lobe-like structure identified in this study remains unknown; however, several hypotheses can be proposed. According to Robinson and Robinson (1979) and Schwarz and Glaw (2021), such structures may function as sex pheromone glands, as reported for A. falcata and S. lobivertex. However, we observed this structure in both sexes during the early developmental stages of S. hebardi, which suggests it may possess an alternative or additional function. Another hypothesis involves the release of prey-attracting pheromones (kairomones), similar to the aggressive mimicry observed in bolas spiders (Mastophora Holmberg, 1876), which mimic lepidopteran sex pheromones to capture prey (Yeargan & Quate, 1997). Finally, this structure might enhance crypsis, similar to strategies observed in the subfamily Vatinae. However, unlike Vatinae, which are characterized by fixed cuticular lobes on the legs or abdominal margins, the structure in S. hebardi is distinctively protrusible.

Acknowledgements

We thank Cristina Mayorga-Martínez for her support in reviewing the CNIN-IBUNAM; Michael R. Maxwell, Henrique M. Rodrigues, and Lohitashwa Garikipati for their comments on an earlier version of this work; Jason D. Weintraub for providing us high resolution images of the holotype and allotype of Stagmomantis hebardi. Aarón Emilio Vásquez Quintero was supported by a scholarship from the Secretaría de Ciencia, Humanidades, Tecnología e Innovación (Secihti; CVU 1315459).

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Revisión de los Elmidae (Coleoptera: Dryopoidea) de Chile

Marcos Ferrú a, b, *, William Shepard c

a Universidad Católica de la Santísima Concepción, Alonso de Ribera 2850, Concepción, Chile
b Centro de Muestreo y Análisis Biológico, Luis Acevedo 456 Chiguayante Bíobío-Concepción, Chile
c University of California, Essig Museum of Entomology, 1101 Valley Life Sciences Bldg., Berkeley, California, 94720 USA

*Corresponding author: marcos.ferru@gmail.com (M. Ferrú)

Received: 12 August 2025; accepted: 17 December 2025

Abstract

The family Elmidae is one of several families of aquatic beetles in the superfamily Dryopoidea. The Elmidae occur throughout the world (except Antarctica), with approximately 150 genera and 1,500 species. Elmidae have been studied as part of the taxa used to assess water quality. There are no keys to identify larvae of Chilean species, and to identify adults it is necessary to remove the male genitalia. Research carried out in Chile has included Elmidae in descriptions, lists and reviews of aquatic beetles in general. Until now, there has been no review dedicated entirely to Chilean Elmidae. In Chile, after this review there are 2 subfamilies, 7 genera and 18 species currently recognized. The species Austrelmis woytkowskii (Hinton), which has been cited in error for Chile, is eliminated from the Chilean list and the species Austrelmis sp. 1 is included, as is Austrolimnius elatus Hinton. Expanded distributions of some species are included.

Keywords: Elmidae; Elminae; Larainae; Diversity; Distribution

Resumen

La familia Elmidae es una de varias familias de escarabajos acuáticos perteneciente a la superfamilia Dryopoidea. Los Elmidae se encuentran en todo el mundo (excepto en la Antártida), con aproximadamente 150 géneros y 1,500 especies. Los Elmidae han sido estudiados como parte de los taxones utilizados para evaluar la calidad del agua. No existen claves para identificar larvas de las especies chilenas y para identificar adultos es necesario extraer los genitales de los machos. Investigaciones realizadas en Chile han incluido a los Elmidae en descripciones, listas y revisiones de escarabajos acuáticos en general. Hasta ahora, no había una revisión dedicada completamente a los Elmidae chilenos. En Chile, después de esta revisión hay 2 subfamilias, 7 géneros y 18 especies actualmente reconocidas. La especie Austrelmis woytkowskii (Hinton), que ha sido citada por error para Chile se elimina de la lista chilena y se incluye la especie Austrelmis sp. 1, al igual que Austrolimnius elatus Hinton. Se incluyen la ampliación de distribuciones de algunas especies.

Palabras clave: Elmidae; Elminae; Larainae; Diversidad; Distribución

Introduction

The family Elmidae (Coleoptera: Dryopoidea) colloquially known as riffle beetles is a group of globally distributed beetles (except for Antarctica) found in clean, permanent waters. Elmidae is divided into 2 subfamilies (Elminae and Larainae), with approximately 150 genera and 1,500 species Jäch et al. (2016) and more taxa are described every year. In Chile, the Elmidae have 2 large faunal divisions. This is a fauna with continental characteristics that shares genera, such as Heterelmis Sharp and Microcylloepus Hinton, with other South American countries. The other faunal area is the Southern Cone, which contains genera shared with New Zealand and Australia, or has genera only shared with Argentina, as is the case of the genera Hydora Anon. [Broun], Luchoelmis Spangler and Staines and Stethelmis Hinton. The different species of Elmidae have similar life cycles. Eggs are laid on submerged substrates such as stones or wood, with hatching occurring in approximately 2 weeks. Pupation lasts about 2 weeks. After about 2 weeks of pupation, the adults emerge, some fly to find new habitats before re-entering the water, while others just re-enter the stream from which they came. Adults can live approximately 10 years (Brown, 1974). Larvae and adults of Elmidae often co-occur in appropriate microhabitats, such as sand, gravel, leaf bundles, aquatic macrophytes, wood, and rocks in clear water, etc. The main requirement for Elmidae is uncontaminated water with high levels of dissolved oxygen, up to moderately polluted environments González-Córdoba et al. (2020). Most Elmidae consume fine particulate organic matter that they browse from the surface or find in the interstitial spaces between gravel particles. This material is usually algae, fungal hyphae, and crushed leaves or wood. The few species that feed on decaying and submerged wood take several years to develop due to the low levels of nutrients wood presents. Reviews of elmid biology are in Brown (1987) and Elliott (2008). Elmidae breathe with tracheal gills (larvae) or plastrons (adults). Both systems require relatively high levels of dissolved oxygen (Brown, 1987; Kodada et al., 2016). Elmidae have been found to be very susceptible to contaminants such as surfactants in soap, petroleum products, accordiong to Brown (1984), Elliott (2008), Lafuente et al. (2019) and anything that removes oxygen from the water. Therefore, their presence in a stream is a sign of uncontaminated water during the lifespan of the Elmidae. Thus, Elmidae are often targeted during water quality assessment programs, along with Ephemeroptera, Plecoptera and Trichoptera, all of which are also susceptible to contaminants (Fierro et al., 2012). When these studies are carried out, it is very important that the sampling considers the microhabitat requirements of the different species. The new global catalog of Elmidae has helped to understand generic and species distributions (Jäch et al., 2016). An identification key for adult genera of South American Elmidae has been developed by Manzo (2005) and an identification key for most larvae of South American Elmidae genera has been developed by Manzo and Archangelsky (2008), Pasos et al. (2018). These have been important scientific advances since Elmidae are an integral part of the ecology of streams and rivers and are often collected during sampling (Fierro et al., 2012). None the less despite its importance there are no keys to identify the larvae to species, and generally to identify the adults it is necessary to extract the male genitalia. The first Elmidae described in Chile are found in 2 articles by Germain (1854, 1892). This was followed by articles published by Champion (1918), Hinton (1941, 1945), Janssens (1957), Spangler and Brown (1981) and Spangler and Staines (2002). Some of the species described in these papers are now found in different genera. Other papers dealing with Chilean dryopoid beetles include authors like Lataste (1897 a, b), Dajos (1974), Solervicens (1974), Shepard (2016) and Shepard and Barr (2023). Nonetheless, the information is scattered and Elmidae continues to be a relatively unknown group. This study will facilitate further efforts on Chilean Elmidae by bringing together information and providing new distribution data.

Materials and methods

The collection of elmid larvae and adults usually involves aquatic nets that are placed downstream of the sampling area where the substrates are disturbed. Elmidae then drifts in the current and into the net. The specimens are collected from the net and preserved in 70% or 95% ethyl alcohol. Some of the net contents collected by WDS were entirely preserved in 95% alcohol bottles and then processed in the laboratory. This makes it easier to collect smaller adults (such as Austrolimnius) and younger larvae. After collecting at each site, ecological characteristics were recorded on field data sheets. Collection locality maps were produced with QGIS and used all known localities, published and new. Locality data are presented primarily as they occur on the specimen labels. A forward slash “/” indicates separate lines in a label and a double forward slash “//” indicates separate labels. Information included by “( )” is below the locality labels. Additional data provided here, but not in the labels, is indicated by brackets “[ ]”. The “WDS-A- ____” numbers refer to WDS data sheets. Collection locality maps were made using ArcGIS and used all known localities, published and new. Additional records of the specimens were obtained from the collections: National Museum of History of Chile (Santiago) and the Museum of the Department of Zoology of the University of Concepción, as well as from published literature on the Elmidae. Abbreviations cited in the text include the following: National Museum of Natural History, Washington, DC, USA (USNM); Natural History Museum, London, England (NHML); Royal Belgian Institute of Natural Sciences, Brusseels, Belgium (RBINS); William D. Shepard (WDS).

Results

As a result of this work, we can consider the diversity of Elmidae to include 18 species, 7 genera and 2 subfamilies. The species Austrelmis woytkowskii (Hinton, 1937) is eliminated because the analysis of samples collected from various streams in northern Chile shows no evidence of its presence. The species Heterelmis trivialis (Germain, 1892) is also eliminated. One of the reasons for this decision is the loss of the type material. Another reason is the fragility of the stream where it was cited; this stream is small and urbanized and tends to have a considerable decrease in its water flow in summer. This species was searched for at the type locality on 2 occasions, thus corroborating its presence in Chile, but it has not been found or reported since its description. In these samplings, the other species described by Germain and cited for the area were found. In this work, the species Austrolimnius elatus, eliminated by Elgueta and Arriagada (1989), is reestablished; this is supported by the type material found. Finally, it is important to mention that despite the limited progress in species richness shown in this work, there are numerous new localities for the different species present in Chile. A list of the Elmidae known from Chile is provided (Table 1).

Key to the genera of adult Elmidae known from Chile extracted from Manzo and Archangelsky (2008) and Passos et al. (2018). 1 Body densely pubescent, without plastron; transverse procoxae, with exposed trochantins; adults fly easily from water or net — Larainae Hydora (Fig. 19). 1’ Body not pubescent, with plastron; procoxa globosa, with unexposed trochantins; adults do not fly from water or net — Elminae (2). 2 Thorax without sublateral carinae (Figs. 27, 30, 32) — 3. 2’ Thorax with sublateral carinae — 4. 3 Tarsal claws with basal teeth (Fig. 31) — Stethelmis. 3’ Tarsal claws without basal teeth — Luchoelmis. 4 Epipleura with 1 or 2 longitudinal lines of granules — Austrolimnius. 4’ Epipleura without longitudinal lines of granules — 5. 5 Pronotum with complete deep transverse groove (Fig. 29) — Neoelmis. 5’ Pronotum without deep transverse groove complete — 6. 6 Pronotum with circular anterior depression, with V-shaped carina in ½ basal, with sublateral elevation (Fig. 28) — Microcylloepus. 6’ Pronotum without depressions; sublateral carina restricted to anterior half (Figs. 25, 26) — Austrelmis.

#	Species	Original generic placement	Author	Endemic
Subfamily Elminae Curtis, 1830
1	Austrelmis anthracina	Elmis	(Germain, 1892)	Yes
2	Austrelmis chilensis	Elmis	(Germain, 1854)	Yes
3	Austrelmis costulata	Macrelmis	(Janssens, 1957)	Yes
4	Austrelmis elegans	Macrelmis	(Hinton, 1937)	No
5	Austrelmis sp.	Macrelmis	(Janssens, 1957)	Yes
6	Austrolimnius chiloensis	Elmis	(Champion, 1918)	Yes
7	Austrolimnius elatus	Austrolimnius	Hinton, 1941	No
8	Austrolimnius nycteloides	Elmis	(Germain, 1854)	No
9	Luchoelmis aequalis	Luchoelmis	Spangler & Staines 2002	Yes
10	Luchoelmis cekalovici	Luchoelmis	Spangler & Staines 2002	No
11	Luchoelmis magallanensis	Luchoelmis	Spangler & Staines 2002	Yes
12	Luchoelmis penai	Luchoelmis	Spangler & Staines 2002	Yes
13	Microcylloepus chilensis	Microcylloepus	Janssens, 1957	Yes
14	Neoelmis scissicollis	Elmis	(Germain, 1892)	Yes
15	Stethelmis chilensis	Stethelmis	Hinton 1945	Yes
16	Stethelmis kaszabi	Stethelmis	Hinton, 1970	No
Subfamily Larainae LeConte, 1861
17	Hydora annectens	Hydora	Spangler & Brown, 1981	No
18	Hydora lenta	Hydora	Spangler & Brown, 1981	Yes

Generic reviews

This section is reproduced from the article PDF; the genus-by-genus accounts (with new distributional records and material examined) are available in full in the linked PDF.

Discussion

The Chilean Elmidae include 2 subfamilies, 7 genera and 17 species. However, many additional species are known but not yet described. Many geographic areas remain unexplored, so additional species are likely to be found. Endemism is relatively high in the Chilean Elmidae, 82.3% (14 of 17 species) of the species are endemic to Chile. The only Chilean Elmidae not endemic to Chile are Austrolimnius elatus, A. nycteloides, and Hydora annectens.

The number of genera and species present in the South American countries on the Pacific slope decreases from north to south (Ecuador to Chile) (Table 2). Partly this is because the northernmost areas are closer to the equator, where temperatures are more favorable to elmid evolution. Also, partly this is due to Ecuador and Peru having areas located on the east front of the Andes near to the Amazon where the evolution of the Elmidae has gone in a different direction (Shepard unpublished data). Chile lacks an Amazonian component.

In Chile, the elmid fauna has been negatively impacted by coastal and Andean orogenies, especially in the north. This is mainly due to the isolation and desertification that characterizes this area (Shepard unpublished data). The only 2 genera present there are Austrelmis and Microcylloepus. Microcylloepus elsewhere has been able to maintain populations in desert environments where small springs or seeps occur, so it is not surprising that it would be found here, while Austrelmis is a very typical inhabitant of high mountain habitats throughout the Andes.

The Southern Cone area of Chile has genera that were thought to be restricted to this area, such as Austrolimnius, Luchoelmis, and Stethelmis. However, Austrolimnius and Stethelmis have now been collected somewhat farther north, Coquimbo in the case of Austrolimnius and Atacama in the case of Stethelmis, nonetheless their diversity remains in the Southern Cone area.

Two collection attempts in the type locality of Heterelmis trivialis failed to find extant populations. It is not known why this population might have disappeared. Likewise, attempts to find populations of Austrelmis woytkowskii were unsuccessful. These findings reinforce the necessity to amplify sampling focused on aquatic coleoptera and Elmidae specifically, in order to determine if these populations are truly extinct or only minimally abundant.

Country	Area (km²)	Number of genera and species	Reference
Colombia	916,445	31 genera and 65 especies	Hincapié-Montoya, 2023
Ecuador	276,841	19 genera and 59 especies	Monte and Mascani, 2012
Perú	1,285,216	17 genera and 51 especies	Shepard and Chaboo, 2015
Chile	756,950	7 genera and 18 especies	This review
Bolivia	1,098,581	12 genera and 33 especies	Manzo and Moya, 2010
Argentina	2,780,400	14 genera and 21 especies	Manzo and Archangelsky, 2014

Acknowledgements

We thank all the people who made this work possible: Walter Sielfeld, for the support on the ground and collection of specimens; Mario Elgueta (National Museum of Natural History); Margarita Ruiz de Gamboa (CEMABIO); Pablo Fierro (Universidad del Valdivia) for his help, contribution of copies and ideas; the specialists Verónica Manzo (University of Tucumán, Argentina) and María Passos (Federal University of the State of Rio de Janeiro, Brazil) for their bibliography. And, finally, the Laboratory of Water Quality Bioindicators EULA-Chile, for their contribution in specimens and land. Additionally, we thank the following people for providing photographs of type specimens and labels under their care: Pol Limbourg (RBINS), Keita Matsumoto (NHML) and Charyn Micheli (USNM).

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Una especie incrustante nueva de Nymphon (Arthropoda: Pycnogonida) de la bahía de La Paz, golfo de California, México

Angel de León-Espinosa, Jesús Angel de León-González *

Universidad Autónoma de Nuevo León, Facultad de Ciencias Biológicas, Laboratorio de Zoología de Invertebrados No Artrópodos, Av. Pedro de Alba s/n, Cd. Universitaria, 66451 San Nicolás de los Garza, Nuevo León, Mexico

*Corresponding author: jesus.deleongn@uanl.edu.mx (J.A. de León-González)

Received: 08 May 2025; accepted: 22 January 2026

http://zoobank.org/urn:lsid:zoobank.org:pub:E99E4A8E-07FD-4A4C-BD8A-80E4BD6A93EA

Abstract

A new species of pycnogonid belonging to the genus Nymphon is described and illustrated from specimens collected at Bahía de La Paz (Gulf of California), where it is part of the dock fouling community. The new species is morphologically similar to Nymphon littus, both species can be separated based on the dentition of the oviger terminal claw, strigilis formula, the relative size of palp segments and chela ornamentation. An identification key for the species reported from the Eastern Pacific is included.

Keywords: Pycnogonid; Nymphonidae; Nymphon childi; Sea of Cortés; Sea spider; Fouling

Resumen

Se describe e ilustra una especie nueva de picnogónido perteneciente al género Nymphon a partir de especímenes recolectados en la bahía de La Paz (golfo de California), donde forma parte de la comunidad de incrustantes en andadores de muelles náuticos. La especie nueva es morfológicamente similar a Nymphon littus; ambas especies pueden distinguirse según la dentición de la uña terminal del ovígero, la fórmula de la strigilis, el tamaño relativo de los segmentos del palpo y la ornamentación de la quela. Se incluye una clave de identificación para las especies reportadas en el Pacífico oriental.

Palabras clave: Picnogónido; Nymphonidae; Nymphon childi; Mar de Cortés; Araña marina; Incrustantes

Introduction

Nymphon Fabricius, 1794 is the most diverse genus of the class Pycnogonida. Currently the genus includes 269 accepted species (Bamber et al., 2026) but a large number of species are poorly described, making difficult its study (Bamber, 1982; Takahashi et al., 2012). Four species of Nymphon have been recorded, so far, in Mexico (Munilla-León, 2002; de León-Espinosa et al., 2021; Ramírez-Tello et al., 2022): N. apheles Child, 1979, described from Panama City, reported also in Bahía de La Paz, Gulf of California (de León-Espinosa et al., 2021), N. floridanum Hedgpeth, 1948 described from Florida and reported in the Yucatán Channel (Stock, 1986); N. lituus Child, 1979 described from the northeastern Gulf of California, with records in the Pacific coast of Panama (Child, 1979), Ojo de Liebre Lagoon on the western coast of Baja California Peninsula (de León-Espinosa & de León-González, 2015), as well as Bahía Banderas, Nayarit (Villatoro-Ortiz & Salazar-Silva, 2022); and N. pixellae Scott, 1912 described from Vancouver, Canada and reported in the Gulf of California by Child (1979).

During a sampling effort carried out at public and private nautical marinas along the west coast of the Gulf of California, specimens of a new species of the genus Nymphon were collected inhabiting with the algae Padina caulescens Thivy, 1945, and the barnacles Tetraclita stalactifera (Lamarck, 1818) fixed to floating docks not deeper than 0.50 m. Type material was deposited in the Colección Carcinológica de la Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo León (UANL-FCB-PYCNO).

Materials and methods

Samples of Nymphon were collected from 3 marine docks located in Bahía de La Paz, Baja California Sur, Mexico (La Paz, Palmira and Cantamar) (Fig. 1). Each encrusting faunal sample was obtained by scraping an area of 400 cm² (20 × 20 cm) located immediately below the sea surface from the edges of the platform and floating docks. The scraping of encrusted fauna was done with a carpenter’s chisel or a spatula following a standard technique (Pech et al., 2023). The encrusted fauna detached from the dock were deposited in plastic bags (Ziploc®) labeled with the date, time and geographic location information for each collection site. The biological samples were later placed in a cooler with seawater obtained from the collection site to transfer to the processing site. At the processing site, specimens from each biological sample were identified and sorted in situ into large taxonomic groups.

The pycnogonid specimens, sorted from the encrusted fauna, were fixed with a 10% formaldehyde solution in 2 mL cryovials. The pycnogonids were then washed a week later with distilled water to remove the excess formalin and salt and then preserved in 70% non-denatured ethanol.

Morphological observations were conducted using a stereomicroscope Olympus SZ, and an Olympus BX51 microscope with differential interference contrast (DIC). The figure backgrounds were cleaned and lightened as necessary, and final figures were assembled on a plate using Paint Shop Pro7. Description of the species is based on the morphology of the holotype.

Description

Class Pycnogonida Latreille, 1810
Order Pantopoda Gerstäcker, 1863
Family Nymphonidae Wilson, 1878
Genus Nymphon Fabricius, 1794
Type species: Nymphon grossipes (O. Fabricius, 1780)

Diagnosis. Trunk usually segmented and elongate. Lateral processes in general are well separated. Ocular tubercle is inserted at the posterior end of the cephalic segment. Abdomen is usually short. Proboscis variable in shape, cylindrical. Cheliphore robust, the scape formed by 1 segment, chelae complete and functional, fingers are long and have teeth of various shape and size. Palps 5-segmented, first one always short; the second one usually longest. The 10-segmented ovigers are present in both sexes, with a strigilis formed by the last 4 segments. They have denticulate spines and usually a toothed terminal claw. Propodus is heelless, main claw usually has auxiliary claws of various sizes. Cement glands, when present, are only present in males and open on the ventral side of the femur.

Remarks. Nymphon the most diverse genus within Pycnogonida, early descriptions are very brief, and type materials are unavailable, making its study very difficult. Traditionally, its species have been placed in artificial groups; however, most species have not been able to be placed in such groups for study.

Nymphon childi sp. nov.
(Fig. 2)

Description. Male holotype (UANL-FCB-PYCNO-0055), trunk slender, fully segmented, neck in front of oviger bases, half the width of trunk, 4.5 times longer than its width, cylindrical, widening in the form of a calyx, with pair of conical, short anterior projections (Fig. 2A, B); lateral processes between first and second pairs separated by 2 times their own diameters, second and third pairs separated by 2.5 times their own diameters, third and fourth pairs separated by their own diameters (Fig. 2A). Ocular tubercle as high as basal width, inserted between first pair of lateral processes and bases of ovigers, cone-shaped, with 2 small papilliform projections, with 2 pigmented pairs of eyes (Fig. 2A, B).

Proboscis cylindrical, longer than wide, horizontal to body (Fig. 2A, B), with 3 smooth lips.

Chelifore scape over-reaching proboscis, chela fingers curved inwards, crossing at tips, 20-21 needle-like teeth of uniform size on each finger, slender, longer than basal part, which is inflated and rectangular, with 5 median ventral spines and 3 large dorsal setae in a row at distal end, next to articulation with movable finger (Fig. 2C).

Abdomen narrowing distally, length over 2 times greatest width, as long as lateral processes of fourth pair of legs, elevated from body at an angle of about 30° (Fig. 2B).

Palps 5-segmented, first segment very short. Second segment longest, with 1 medio-dorsal seta and a large dorso-distal 1. Third segment about 2/3 length of segment 2 with line of 3 ventral setae and latero-distal one; with medio-dorsal small seta. Fourth segment 4.5 times as long as segment 1, with ventral row of 7 setae. Fifth segment 1.1 times as long as fourth segment, with 9 long ventral setae, medio-dorsal small seta, terminal end with cluster of 4 setae (Fig. 2D).

Oviger 10-segmented, inserted in distal half of first lateral processes (Fig. 2B). First 3 segments short, first segment half size of second one, second and third segments subequal. Fourth segment with dorsal seta and ventro-distal one. Fifth segment 1.6 times longer than fourth, with ventral row of 11 setae, dorsal surface bare. Sixth segment as long as first and second segments together, with ventral row of 14 setae. Last 4 segments compose the strigilis, armed with compound ovigerous leg spines, each with the following formula: 12: 7: 5: 8. Compound spines with 3-6 pairs of lateral teeth depending upon the size of the spine. Terminal claw long, curved, with 6 teeth (Fig. 2G). First segment of strigilis with transverse row of 4 distal setae, second one with 2 dorsal isolated setae and distal row with 4 setae, in both dorsal setae longest; third segment with 3 dorsal setae and group of 4 dorso-distal setae; fourth strigilis segment with row of 8 dorsal setae (Fig. 2F, G).

Third leg (Fig. 2E), coxa 1 short, without setae. Coxa 2, 3.3 times longer than coxa 1, with 3 ventral setae. Coxa 3 slightly longer than coxa 1, with row of 6 small ventral setae. Femur long, with 10 scattered ventral setae. Tibia 1 with row of 6 long median-dorsal chaetae and distal spine, ventral row of 10 smaller setae. Tibia 2, 1.3 longer than tibia 1, with row of 17 dorsal setae and 3 median and distal spines, 24 small ventral setae and 1 distal spine. Tarsus with dorsal row of 4 setae, and 7 ventral setae and distal spine. Propodus 2.2 times longer than tarsus, slightly curved, with dorsal row of 13 spines and setae, and row of 22 ventral setae. Main claw short, less than ¼ length of propodus, auxiliary claws nearly as long as main claw.

Measurements of holotype (mm). Trunk length (frontal margin of cephalic segment to tip of fourth lateral process), 2.31; cephalon length, 1.04; width across 2nd lateral processes, 0.93; proboscis length, 0.53; proboscis greatest diameter, 0.22; abdomen length (lateral), 0.22. Palp: seg. 1, 0.05; seg. 2, 0.55; seg. 3, 0.44; seg. 4, 0.24; seg. 5, 0.25. Oviger: seg. 1, 0.13; seg. 2, 0.28; seg. 3, 0.28; seg. 4, 0.8; seg. 5, 1.3; seg. 6, 0.41; seg. 7, 0.3; seg. 8, 0.22; seg. 9, 0.13; seg. 10, 0.17; claw, 0.09. Third leg: coxa 1, 0.28; coxa 2, 0.87; coxa 3, 0.33; femur, 1.99; tibia 1, 2.5; tibia 2, 3.26; tarsus, 0.41; propodus, 0.81; claw, 0.25.

Female paratype (UANL-FCB-PYCNO-0056). Gonopores oval-shaped, present on ventrodistal end of coxa 2 in all leg pairs.

Taxonomic summary

Etymology. This species is named in honor of Dr. C. Allan Child (Department of Invertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington) in recognition of his life dedicated to the study of Pycnogonida. The species-group name is a noun in the genitive case (ICZN 1999, Art. 31.1.2).

Type material. Holotype (1 male), (UANL-FCB-PYCNO-0055), paratypes (1 male and 4 females), (UANL-FCB-PYCNO-0056), Marina La Paz, La Paz, Baja California Sur, Mexico, 24°07’29.3” N, 110°20’47.3” W, 3 September 2013.

Additional material. One specimen (female), (UANL-FCB-PYCNO-0059), Marina La Paz, La Paz, Baja California Sur, Mexico, 24°07’29.3” N, 110°20’47.3” W, 14 August 2011. One specimen (male), (UANL-FCB-PYCNO-0057), Marina Palmira, La Paz, Baja California Sur, Mexico, 24°11’05.3” N, 110°18’12.7” W, 3 April 2011; 10 specimens (male), (UANL-FCB-PYCNO-0058), same locality, 15 August 2011. Two specimens (1 male and 1 female), (UANL-FCB-PYCNO-0060), Marina Cantamar, La Paz, Baja California Sur, Mexico, 24°16’44” N, 110°19’49” W, 26 June 2017.

Remarks

From the current Nymphon species known in the world, 21 have been reported from both coasts of America, 10 of these from the Eastern Pacific: N. aculeatum Child, 1994 (California, Oregon); N. apheles Child, 1979 (Panama); N. duospinum (Hilton, 1942) (Alaska); N. heterodenticulatum Hedgpeth, 1941 (Santa Catalina Island, California); N. hirsutum Child, 1995 (Bering Sea); N. lituus Child, 1979 (Gulf of California and Panama); N. longicollum Hoek, 1881 (Chile); N. pixellae Scott, 1912 (Vancouver, Oregon, Gulf of California); P. simulare Child, 1992 (Ecuador) and N. stipulum Child, 1990 (California).

Nymphon childi sp. nov. is morphologically similar to N. lituus Child, 1979 and N. simulare Child, 1992, all have a slender body, the third metamere of the body is longer than wide, the neck is 4 or more times longer than wide, and the tarsus is less than 50% of the length of the propodus. Nymphon childi sp. nov. differ from these species in the following characteristics: 1) the anterior tubercle over insertion of chelifores, conical in N. childi sp. nov., and as low anteriorly curved tubercle in N. lituus, N. simulare does not present anterior tubercles; 2) strigilis formula, of 12: 7: 5: 8 in N. childi sp. nov., 15: 10: 10: 11 in N. littus, and 11:10:10:10 in N. simulare; 3) second segment of the palp is shorter than third and fourth together in N. childi sp. nov. and N. simulare, and sligthly longer in N. littus; 4) third segment of the palp is 1.5 times longer than the fifth in N. childi sp. nov. and N. simulare and subequal to the fifth one in N. littus; 5) chela fingers, with 23 teeth in both chelae in N. childi sp. nov, immovable finger has 29 teeth, movable finger with 33 teeth in N. littus, and 27-28 teeth in N. simulare.

Another closer species to Nymphon childi sp. nov. is N. heterodenticulatum, both have the same structural body plan, proboscis horizontal to body, with a long cylindrical neck longer than wide ending in a structure with calyx shape, similar lateral processes separation, and abdomen shape. However, N. heterodenticulatum presents the ocular tubercle sharply pointed, ending in a cone shaped structure, chelifores with slender chela, fixed finger with 17 teeth, movable finger with 19 teeth; oviger with strigilis with a formula of 9: 9: 7: 7.

This species is currently known only from the type locality: Bahía de La Paz, Baja California Sur, Mexico, attached to dock fouling not deeper than 0.5 m.

Key to Nymphon species from Eastern Pacific

1. Tarsus longer than propodus … 2
— Tarsus shorter than propodus … 4
2. Ocular tubercle well developed; auxiliary claw present; fourth and fifth segment of palp equal in size … 3
— Ocular tubercle and eyes lacking; auxiliary claws absent; fourth segment of palp shorter than the fifth one … N. aculeatum Child, 1994 (California)
3. Auxiliary claws less than half the length of the main claw; strigilis of oviger as follow 20:9:14:12; terminal claw of oviger with 15-17 teeth; movable finger of chela with 35 thin teeth; immovable finger with 20 teeth … N. pixellae Scott, 1912 (Vancouver, Canada)
— Auxiliary claws slightly longer than the main claw; strigilis of oviger as follow 10: 9: 8: 10; terminal claw of oviger with 8 teeth; movable finger of chela with 19 teeth; immovable finger with 17 teeth … N. heterodenticulatum Hedgepeth, 1941 (Santa Catalina Island, California)
4. Short neck, less than twice own width … 5
— Long neck, more than twice own width … 7
5. Auxiliary claws less than half the length of the main claw; cheliphore with long and thin scape … 6
— Auxiliary claws longer than half the length of the main claw; cheliphore with short and robust scape … N. apheles Child, 1979 (Panama)
6. Palp with third segment longer than second one, with a group of long distal chaetae; tarsus longer than half the size of the propodus … N. stipulum Child, 1990 (California)
— Palp with third segment shorter than second one, with short chaetae along surface; tarsus shorter than half the size of the propodus … N. duospinum (Hilton, 1942) (Alaska)
7. Auxiliary claws thin and small, less than ¼ the size of the main claw; chelae with few teeth on both fingers, movable finger with 8 teeth, immovable finger with 5 teeth … N. longicollum Hoek, 1881 (Chile)
— Auxiliary claws equal to, or longer than half the size of the terminal claw … 8
8. Fingers of the chelae shorter than palm, movable finger with 34 teeth, immovable finger with 26 teeth; oviger with strigilis as follow 11: 6: 6: 6; oviger claw with 20 teeth … N. hirsutum Child, 1995 (Bering Sea)
— Fingers of the chelae longer than palm … 9
9. Oviger with strigilis as follow 12: 7: 5: 8; movable finger of chelae with 20 teeth, immovable finger with 20-21 teeth … N. childi sp. nov. (Bahía de La Paz, Gulf of California)
— Last 3 segments of the strigilis with 10 or more compound spines; chelae fingers with more than 20 teeth each … 10
10. Third segment of the palp similar in size of the second one; distal end of neck without distal tubercules … N. simulare Child, 1992 (El Viejo Island, Ecuador)
— Third segment of the palp ½ the size of the second one; distal end of neck with anteriorly curved low tubercle over insertion of chelifores … N. lituus Child, 1979 (Puerto Peñasco, Gulf of California)

Acknowledgements

This work was financially supported by the Universidad Autónoma de Nuevo León (grant number PAICYT 0235). Many thanks to Jesús Flores and Jesús Mendieta for their technical help with the collections and sorting out the specimens from the samples. This work could not be completed without the support of Claudia Arango, Lyudmila Slucheusky and Isabell Clasen who sent us some relevant scientific literature. We thank Mariana Tovar-Hernández for her review of the manuscript, and an anonymous reviewer.

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