Morphological and molecular data reveal a new species of Neoechinorhynchus (Acanthocephala: Neoechinorhynchidae) from Dormitator maculatus in the Gulf of Mexico Carlos Daniel Pinacho-Pinacho a , Ana L. Sereno-Uribe b , Martín García-Varela b, ⁎ a Posgrado en Ciencias Biológicas, Instituto de Biología, Universidad Nacional Autónoma de México, A.P. 70-153, C.P. 04510 México D.F., México b Departamento de Zoología, Instituto de Biología, Universidad Nacional Autónoma de México, A.P. 70-153, C.P. 04510 México D.F., México abstract article info Article history: Received 24 December 2013 Received in revised form 5 July 2014 Accepted 12 July 2014 Available online 23 July 2014 Keywords: Acanthocephala Neoechinorhynchus (Neoechinorhynchus) mexicoensis Morphology Molecular data ITS LSU Gulf of Mexico Dormitator maculatus Neoechinorhynchus (Neoechinorhynchus) mexicoensis sp. n. is described from the intestine of Dormitator maculatus (Bloch 1792) collected in 5 coastal localities from the Gulf of Mexico. The new species is mainly distinguished from the other 33 described species of Neoechinorhynchus from the Americas associated with freshwater, marine and brackish fishes by having smaller middle and posterior hooks and possessing a small proboscis with three rows of six hooks each, apical hooks longer than other hooks and extending to the same level as the posterior hooks, 1 giant nucleus in the ventral body wall and females with eggs longer than other congeneric species. Sequences of the internal transcribed spacer (ITS) and the large subunit (LSU) of ribosomal DNA including the domain D2 + D3 were used independently to corroborate the morphological distinction among the new species and other congeneric species associated with freshwater and brackish water fish from Mexico. The genetic divergence estimated among congeneric species ranged from 7.34 to 44% for ITS and from 1.65 to 32.9% for LSU. Maximum likelihood and Bayesian inference analyses with each dataset showed that the 25 specimens analyzed from 5 localities of the coast of the Gulf of Mexico parasitizing D. maculatus represent an independent clade with strong bootstrap support and posterior probabilities. The morphological evidence, plus the monophyly in the phylogenetic analyses, indicates that the acanthocephalans collected from intestine of D. maculatus from the Gulf of Mexico represent a new species, herein named N. (N.) mexicoensis sp. n. © 2014 Published by Elsevier Ireland Ltd. 1. Introduction The fat sleeper fish, Dormitator maculatus (Eleotridae) (Bloch 1792), is distributed in the Atlantic Ocean from North Carolina of the south- eastern United States to southeastern Brazil including the West Indies [1]. It represents an important local source of food for humans along the coast of the Gulf of Mexico [2]. The biology of the fat sleeper is well known; it lives in freshwater and brackish water, streams, rivers, springs, lagoons, swamps, and muddy ponds [1]. Its diet is mostly composed of zooplanktonic microcrustaceans and phytoplankton [2]. Species of Neoechinorhynchus Stiles and Hassall, 1905 are endoparasites of freshwater brackish water fish and freshwater turtles with approxi- mately 116 described species classified into two subgenera: Neoechinorhynchus Hamann 1892 and Hebesoma Van Cleave 1928 distributed worldwide [3,4]. A total of 49 species have been described from the Americas, 33 from North America and 16 from Central and South America [5–9]. In Mexico, 8 species belonging to the subgenus Neoechinorhynchus have been described, 2 of these occur in freshwater turtles, i.e., Neoechinorhynchus (Neoechinorhynchus) schmidti Barger, Thatcher and Nickol, 2004 and Neoechinorhynchus (Neoechinorhynchus) emyditoides Fisher, 1960, and the other 6 species occur in marine, brackish and fresh- water fishes: Neoechinorhynchus (Neoechinorhynchus) roseum Salgado- Maldonado, 1978; Neoechinorhynchus (Neoechinorhynchus) golvani, Salgado-Maldonado, 1978; Neoechinorhynchus (Neoechinorhynchus) chimalapasensis Salgado-Maldonado, Caspeta-Mandujano and Martínez- Ramírez, 2010; Neoechinorhynchus (Neoechinorhynchus) brentnickoli Monks, Pulido-Flores and Violante-González, 2011; Neoechinorhynchus (Neoechinorhynchus) mamesi Pinacho-Pinacho, Peréz-Ponce de Léon and García-Varela, 2012; and Neoechinorhynchus (Neoechinorhynchus) panucensis Salgado-Maldonado, 2013 [8–11]. During a helminthological survey, adult acanthocephalans were collected in the intestine of the fat sleeper fish D. maculatus in five local- ities from the Gulf of Mexico. These acanthocephalans represent an undescribed species of Neoechinorhynchus, which is herein described and compared with the other 33 species from the Americas associated with freshwater, marine and brackish fishes. Molecular data were gen- erated from Neoechinorhynchus and compared with the other species previously recorded in Mexico. ⁎ Corresponding author. Tel.: +52 5 56229130; fax: +52 5 55500164. E-mail address: garciav@servidor.unam.mx (M. García-Varela). Parasitology International 63 (2014) 763–771 http://dx.doi.org/10.1016/j.parint.2014.07.003 1383-5769/© 2014 Published by Elsevier Ireland Ltd. Contents lists available at ScienceDirect Parasitology International journal homepage: www.elsevier.com/locate/parint