Ligyrus (Ligyrus) nasutus
Creators: name: López-García, Margarita M.
name: Deloya, Cuauhtémoc
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Dynastidae
Ligyrus
Ligyrus nasutus

description: Ligyrus (Ligyrus) nasutus (Burmeister, 1847) revised status
(Figs. 1F, 15N, 18F, 26C; 34)
Podalgus nasutus Burmeister, 1847: 120. Original combination.
Female lectotype designated by Endrödi (1969: 59) (MLUH) “nasutus* / Yucat. / Berg // Lectotypus / Ligyrus / (Podalgus) / nasutus Burm / Endrody” Type locality: Guatemala and Yucatan. Although Guatemala is mentioned in the original description no paralectotype was found.
Ligyrus pygidialis Bates, 1888: 317. Original combination. Male lectotype designated by Endrödi (1969: 59) (BMNH) “LECTO- / TYPE // Type // B.C.A., Col.,II(2) / Ligyrus / pygidialis. // N. Yucatan. / Gaumer. // Ligyrus / pygidialis / Bates ♂ // Lectotypus / Ligyrus / pygidialis / Bat. / Endrody”. Female paralectotype (BMNH) “PARA- / LECTO- / TYPE // Type // B.C.A., Col.,II(2) / Ligyrus / pygidialis. // N. Yucatan. / Gaumer. // Ligyrus / pygidialis / Bates ♀ ”. Male paralectotype (BMNH) “PARA- / LECTO- / TYPE // B.C.A., Col.,II(2) / Ligyrus / pygidialis. // N. Yucatan. / Gaumer.”. There are 13 syntypes which should be labeled as paralectotypes at MNHN (EC7079-7091). The following are considered invalid types as the species was not originally described with paratypes: Two male paratypes and two female paratypes (USNM) “ Yucatan / Temax / Gaumer // USNM / PARATYPE / 49710 // Ligyrus / pygidialis / Bates / Paratype ”.
Description. Habitus as in Fig. 26C. Length 14.8–17.4 mm; humeral width 8.31–9.2 mm. Color dark reddish brown. Head: Frons deeply rugopunctate, with large and sparse punctures, nearly smooth on vertex, with only sparse, small punctures. Frontoclypeal region with a bilobed, complete carina (Fig. 1F). Ocular canthus acute, with 10 ventral setae. Clypeal surface rugopunctate to transversely rugose, striae denser than those on frons. Clypeus triangular, base 3.5 times wider than apex (Fig. 1F). Clypeal teeth triangular, separated by 1 diameter tooth (Fig. 1F). Mandible with 2 apical and 1 lateral, widely rounded tooth, tooth 1 longer and narrower than tooth 2. Maxilla rectangular; galea with 3 dorsal teeth. Apex of labrum straight. Interocular distance 3.5 times an eye width. Antennal club very long. Pronotum: Surface with large, dense punctures. Apex without tubercle (with a small swelling) or fovea. Elytra: First interval punctate, punctures similar to other intervals. Inner surface of apex with small transverse tubercles forming about 70 parallel lines. Abdomen: Apex of tergite IV with a diagonal line of 11 transverse, parallel, short carinae. Pygidial surface with small punctures, denser on base and anterior corners. Surface in lateral view strongly convex (male) to flat (female). Legs: Protibia tridentate, basal tooth slightly distant from others. Protibial surface sparsely punctate. Protarsus of male simple, inner claw simple. Metatibia strongly contracted at apex. Apex of metatibia entire, with 15–20 spinules. Female genitalia: Subcoxite subrectangular (2 times wider than long). Coxite subrectangular (wider than long); surface strongly concave. Subcoxite wider and shorter than coxite. Male genitalia: Spiculum gastrale thin, apex truncate. Parameres with sides nearly parallel, lateral ventral teeth long (Figs. 15N, 18F). Internal sac with lamellar spiny belt long (5 times longer than copulatory lamellae); accessory lamella thickened, irregular.
Diagnosis. Ligyrus nasutus can be recognized by the frontal carina bilobed, not interrupted (Fig. 1F); pronotum without tubercle or fovea, with a basal small swelling (Fig. 26C); pronotal punctation deep and large; metatibia elongate with apex strongly narrowed; parameres with sides nearly parallel; lateral ventral teeth long (Figs. 15N, 18F); internal sac with accessory lamella thick and irregular (as in L. allonasutus, Fig. 21E); coxite of female strongly concave.
Taxonomic remarks. Ligyrus nasutus was described with two females, one from Yucatán and the other from Guatemala. Ligyrus pygidialis was described by Bates (1888) based on a large series of males and females from Yucatán (Mexico), which according to his description were different to L. nasutus by the shape of the frontoclypeal carina divided at middle. It is not clear if Bates (1888) reviewed the type specimen of L. nasutus of Yucatán, but he cited additional specimens from Guerrero (Mexico) and San Jerónimo (Guatemala). Endrödi (1969) chose the female from Yucatán (in poor condition) as the lectotype for L. nasutus and considered L. pygidialis as an “aberration”. He only described and illustrated the parameres from the populations from western Mexico and Guatemala to Costa Rica but did not illustrate the parameres of the Yucatán populations, even though the lectotype of L. nasutus was from this region. After his work, the name L. nasutus was widely used for supposedly a unique species with wide distribution, but there was confusion since the original description of Burmeister included two female specimens from different species as types for L. nasutus. In the present work, the lectotypes of L. nasutus and L. pygidialis were analyzed in comparison with additional specimens from the region of Yucatán and compared with specimens from other regions of Mexico and Guatemala to Panama. Clear differences were found between the specimens from Yucatán region and the other populations, mainly in the shape of the frontoclypeal carina, pronotum, and parameres, which is supported by the biogeographic identity of the region of Yucatán. Following the International Commission on Zoological Nomenclature (1999), as the lectotype of L. nasutus is from Yucatán, only the populations of this region correspond to this species, and the remaining populations from western Mexico to Panama are named in the present work as L. allonasutus.
Distribution. Ligyrus nasutus is restricted to the Yucatán region of Mexico, in the states of Campeche, Yucatán, Quintana Roo, and eastern Chiapas at elevations below 50 m.
Locality records (Fig. 34). 62 examined specimens from BMNH, CNIN, EMAC, IEXA, UNSM, USNM. Some data from Ratcliffe et al. (2013). MEXICO (81). Campeche (16): Calkini; Campeche (5 mi. N); Grutas Xtacambilxunán. Chiapas (1): Palenque. Quintana Roo (12): Cancún; Carrillo Puerto (20–24 km N); Cobá; Nuevo X-Can; Playa del Carmen (10.9 km S). Yucatán (51): Chichén Itzá; Conkal; Mérida; Piste (12 km N); Santa Helena; Temax.
description: Published as part of López-García, Margarita M. & Deloya, Cuauhtémoc, 2022, Cladistic analysis reveals polyphyly of Tomarus (Coleoptera: Scarabaeidae: Dynastinae): new classification and taxonomic revision, pp. 1-119 in Zootaxa 5211 (1) on pages 46-47, DOI: 10.11646/zootaxa.5211.1.1, http://zenodo.org/record/7345007