A morphological, phylogenetic and phylogeographic reappraisal of the land crabs Gecarcinus quadratus De Saussure, 1853, and G. lateralis Fréminville in Guérin 1832 (Decapoda: Gecarcinidae). Are they different species? Author Toledano-Carrasco, Ia Atzimba 0000-0001-6918-2509 Colección Nacional de Crustáceos, Instituto de Biología, Universidad Nacional Autónoma de México, 04510 Ciudad de México, México iaia @ comunidad. unam. mx; https: // orcid. org / 0000 - 0001 - 6918 - 2509 iaia@comunidad.unam.mx Author Villalobos, José Luis Colección Nacional de Crustáceos, Instituto de Biología, Universidad Nacional Autónoma de México, 04510 Ciudad de México, México iaia @ comunidad. unam. mx; https: // orcid. org / 0000 - 0001 - 6918 - 2509 Author Álvarez, Fernando Colección Nacional de Crustáceos, Instituto de Biología, Universidad Nacional Autónoma de México, 04510 Ciudad de México, México iaia @ comunidad. unam. mx; https: // orcid. org / 0000 - 0001 - 6918 - 2509 text Zootaxa 2021 2021-10-06 5048 2 215 236 journal article 4119 10.11646/zootaxa.5048.2.4 77661b3d-321c-46e7-9830-56ce49fbe33c 1175-5326 5552003 7B70B5E3-9B0D-4AB3-ADDC-ECD2ABB2AB48 Gecarcinus lateralis Fréminville in Guérin, 1832 ( Figs. 1A; 2A-D; 3A, D ) Gecarcinus lateralis Fréminville in Guérin 1832 : 7, pl. 5, figs. 1, 1a–b. Ocypoda lateralis .— Fréminville 1835: 224 . Gecarcinus lateralis .—H. Milne-Edwards 1837: 27 , pl. 18, figs. 1–6. De Saussure 1858: 440 . Geocarcinus lateralis .— Young 1900: 239 . Gecarcinus lateralis .— Rathbun 1918: 355 . Chace & Hobbs 1969: 198 . Gecarcinus (Gecarcinus) lateralis lateralis .— Türkay 1970: 337 . Gecarcinus (Gecarcinus) lateralis .— Türkay 1973: 974 . Gecarcinus lateralis .— Powers 1977: 139 . Gecarcinus (Gecarcinus) lateralis lateralis .— von Prahl & Manjarrés 1984: 158 . Gecarcinus lateralis .— Abele & Kim 1986: 661 . Hernández-Aguilera 1996: 92 . Schubart et al . 2006: 195 . Ng e t al . 2008: 215. Felder et al . 2009: 1088 . Low et al . 2013: 101 . Perger & Wall 2014: 97 . Hermoso-Salazar & Arvizu-Coyotzi 2015: 21 . Guinot et al . 2018: 568-570 . Toledano-Carrasco 2019: 18-22 . Ng et al . 2019: 99-100 . Material examined. MEXICO . Tamaulipas : 2 females , 1 juvenile , CCLEA C86–07182 , Municipality San Fernando , La Laguna , Boca de Catán , Apr 04, 2014 , coll. G. Rodríguez ; 1 female , CCLEA , C86–07094 , Municipality Soto La Marina , La Pesca , Oct 20, 2014 , coll. G. Rodríguez ; 1 male , 1 female , CCLEA C86–07094 jar D, same locality and collector data as previous, Sept 24, 2016 .– Veracruz : 1 male , CCLEA C86–06601 , Municipality Cazones , Barra de Cazones , Jan 24, 2015 , coll. G. Rodríguez ; 2 males , 1 female , CNCR 33942 , Municipality Ángel R . Cabada , Río Prieto , coll. anonymous ; 2 males , CNCR 33943 , Municipality Catemaco , Barra de Sontecomapan , Apr 24, 2017 , colls. I. Toledano , E. Moreno , J.L. Villalobos .– Tabasco : 1 male , CCLEA C86-06495 , Municipality Paraíso , Playa Bruja , Oct 14, 2006 , coll. G. Rodríguez ; 1 male , 1 female , CCLEA , C86-06500 , Municipality Paraíso , Chiltepec , Apr 06, 2007 , coll. G. Rodríguez. – Campeche : 2 males , 1 female , CNCR 34011 Cayo Arcas , Apr 06, 2017 , coll. anonymous; 1 female , CCY YUC-CC-255-11 - 001024 , Municipality Progreso , Arrecife Alacranes , Aug 01, 2009 , coll. C. Cinthya Delgado. – Quintana Roo : 1 male , 2 juveniles , CNCR 34010 , Municipality Othón P. Blanco , Playa Mahahual , Mar 12, 2017 , coll. Anonymous ; 1 male , CNCR 30834 , Isla Cayo Norte Menor , Banco Chinchorro , Mar 28, 2013 , coll. anonymous. Diagnosis. Male abdomen triangular; telson campanulate, narrower than sixth abdominal somite, lateral margins slightly marked, tip rounded. Sixth somite with convex lateral margins, forming lateral shoulder ( Fig. 2B ). Female abdomen subcircular, completely or almost completely covering thoracic sterna; telson triangular, as wide as posterior margin of sixth somite, lateral margins straight, smooth ( Fig. 3D ). Antero-lateral margins of sternite 3 slightly convex, those of sternite 4 straight, with slight concavity ( Figs. 2B , 3D ). Shallow endostomial ridges delimiting efferent branchial channel, poorly defining this region. Third maxilliped with merus generally concealing epistome. Adult male chelae different in size and robustness; inner surface of palm of major chela with longitudinal tuberculated ridge, used as stridulatory plectrum. Description. Based on adult male with G1 well developed ( 54.3 mm CL, 71.7 mm CW). Carapace transversely oval, wider anteriorly, strongly arched at level of branchial regions, anterolateral margin incipient, posterior portion of external orbital angle slightly marked, armed with minuscule granules. Regions well defined, delimited by shallow grooves. Branchial regions prominent. Fronto-orbital margin about 1/2 of maximum carapace width (Fig. 1A). Front about 1/4 length of carapace, deflexed, surface slightly concave, occasionally straight, inferior margin granulated, raised from surface, straight, generally concealing basal segments of antennules; frontal lobes poorly defined ( Fig. 2A ). Orbits delimited by well defined, smooth superior border. Infra-orbital margin granulated, interrupted by deep notch, continued as triangular plate forming mesial lobe. Suborbital ridge well marked (stridulating crest of Guinot et al . 2018 ), extending from superior border of epistome to subhepatic suture. Surface of anterolateral wall of carapace reticulated (pars strident). Third maxillipeds not closing completely, leaving rhomboidal gap; merus covering epistome anteriorly, anterior border with medial notch, occasionally straight; ischium longer than merus, subequal in width. Palp short, hidden and articulated behind merus, directed laterally ( Fig. 2A ). Short exognath hidden behind ischium. Strong heterochely in males, subequal chelipeds in females; fingers longer than palm, with corneous tips; longitudinal rows of granules throughout surface; cutting margins bearing 6–8 irregularly spaced blunt teeth; dactyl slightly curved inwards; fingers gapping ( Fig. 2D ). Internal surface of palm swollen, with distinct longitudinal ridge along midsection, used as stridulatory plectrum, internal depression next to articulation with carpus. Carpus subtriangular, dorso-mesial margin smooth in large organisms, spinulous in small ones. Merus elongated, subtriangular, internal border granulated. Pereiopods (2–4) long, slender, with short setae; merus elongated, surface striated; carpus subtriangular, shorter than propodus, or almost of same length in fifth pair, dorsal margin toothed; propodus shorter than dactyl, dorsal and ventral margins formed by short, slender spines; dactyli armed with 4–6 rows of spines, those on lateral carina poorly developed to absent ( Fig. 2C ). Male and female abdomen as in species diagnosis. Male G1, as in genus diagnosis ( Fig. 3A ). Female ( 39 mm CL, 33–50 mm CW), with gonopore on sixth plate of thoracic sternum, protruding. Ring around operculum oval, with sharp edges; operculum a large, oval, protruding lobe. Coloration . Dorsal surface of carapace dark, lateral margins orange, posteriorly light cream. Chelipeds and lower portion of front orange (Fig. 1A) Measurements. Males: 28.6–49.1 mm CL; 33.9–64.5 mm CW. Females 27.3–39 mm CL, 33–50 mm CW. Remarks. The authorship of the species was attributed to Fréminville (1835) for many years who originally named organisms from the French West Indies: Marie-Galante, La Désirade, Guadeloupe and Martinique , as Ocypode lateralis . However, Low et al. (2013) reported that Guérin in 1832 had already used the name “ Gecarcinus lateralis Freminv. ” in his Iconographie du Règne animal by G. Cuvier and, hence, he must be recognized as the author of the species.