Neotropical Ichthyology, 5(3):271-278, 2007 Copyright © 2007 Sociedade Brasileira de Ictiologia Hypostomus chrysostiktos, a new species of armored catfish (Siluriformes: Loricariidae) from rio Paraguaçu, Bahia State, Brazil José L. O. Birindelli*, Angela M. Zanata** and Flávio C. T. Lima* Hypostomus chrysostiktos, a new species of armored catfish of the family Loricariidae, is described. The most remarkable characteristic of the new species, which allows its prompt diagnosis from congeners, is the high number of branched rays in the dorsal fin (10-11). In addition, the new species can be diagnosed from the remaining Loricariidae by the combination of the following characters: slightly evertible cheek plates, four branched anal-fin rays, naked abdomen, and snout almost completely plated. The characters states shared by H. chrysostiktos and the tribe Hypostomini, which indicates it as belonging to that group, are: a hatched-shaped opercle, the anterior process of the pterotic-supracleitrum passing halfway the orbit, a pointed post-cleithral process, and slightly evertible cheek plates. The description of this armored catfish provides more evidence for the high level of endemism in the ichthyofauna of rio Paraguaçu basin, a coastal river of northeastern Brazil. Uma nova espécie de cascudo da família Loricariidae, Hypostomus chrysostiktos, é descrita. A característica mais marcante da nova espécie, que permite diagnosticá-la das congêneres, é o grande número de raios ramificados da nadadeira dorsal (10-11). A nova espécie pode ser ainda diagnosticada dos demais Loricariidae pela combinação dos seguintes caracteres: placas laterais da cabeça levemente eversíveis, quatro raios ramificados na nadadeira anal, abdômen nu, e focinho quase completamente coberto por placas. Os estados de caracteres compartilhados entre H. chrysostiktos e a tribo Hypostomini, os quais indicam que a nova espécie pertence ao grupo, são: opérculo em forma de machado, processo anterior do pterótico-supracleitro passando metade da órbita, processo pós-cleitral afilado, e placas laterais da cabeça levemente eversíveis. A descrição deste cascudo é outro exemplo que evidencia o alto grau de endemismo da ictiofauna da bacia do rio Paraguaçu, uma drenagem costeira do nordeste brasileiro. Key words: Hypostominae, Hypostomini, Eeastern brazilian drainages. Introduction comment on Hypostomus taxonomy remains valid. More re- cently, the most meaningful contributions to the systematics The armored catfish family Loricariidae, with over 690 spe- of the genus were regional revisions, such as Boeseman (1968, cies in 70 genera (Reis et al., 2003), is the most diverse within 1969), Reis et al. (1990), Mazzoni et al. (1994), and Oyakawa et the order Siluriformes and is one of the largest of all fish fami- al. (2005), or revisions on monophyletic subunits of the ge- lies, distributed from Costa Rica in Central America to La Plata nus (e.g., Armbruster, 1998a, 2003; Hollanda Carvalho & We- basin in Southern South America. The genus Hypostomus ber, 2004). There are still much to be clarified concerning spe- Lacepède is the most speciose within the family Loricariidae, cies limits within the genus. with approximately 130 species recognized as valid, and an There have been relatively few studies addressing the re- estimated one third more still to be described (Weber, 2003; lationships within Loricariidae (e.g., Howes, 1983; Schaefer, Hollanda Carvalho & Weber, 2004). Coupled with the elevated 1987; Montoya-Burgos et al., 1997, 2002; Armbruster, 2004). number of species, the considerable intraspecific variation The most recent and detailed analysis was presented by has caused problems in delimiting species within the genus. Armbruster (2004), which proposed major rearrangements in To quote Gosline (1947: 111): “the taxonomist trying to iden- the taxonomy of the higher taxa of the family. The most impor- tify a specimen of Plecostomus (= Hypostomus) will probably tant change was the fusion of the majority of Hypostominae feel disgruntled to find himself presented with a problem rather (sensu Isbrücker, 1980) with the Ancistrinae (sensu Isbrücker, than a name”. Even though 60 years have elapsed since, that 1980) into a single subfamily, Hypostominae. Armbruster (2004) *Museu de Zoologia da Universidade de São Paulo, Caixa Postal 42494, 04218-970 São Paulo, SP, Brazil. [email protected]; [email protected] **Departamento de Zoologia, Instituto de Biologia, Universidade Federal da Bahia, Rua Barão de Geremoabo, s/n, Ondina, 40170-290 Salvador, BA, Brazil. [email protected] 271 272 A new species of armored catfish recognized five monophyletic tribes within it: MacClade version 4.06 (Maddison & Maddison). The analysis Corymbophanini, Rhinelepini, Hypostomini, was performed using PAUP version 4.0b10 (Swofford), using Pterygoplichthyni, and Ancistrini. All the former genera the tree bisection-reconnection in a heuristic search. Charac- included in the tribe Hypostomini (Cochliodon, ters were ordered as indicated by Armbruster (2004). Aphanotorulus, Isorineloricaria, Cheirododus, Squaliforma Specimens examined belong to the following institutions: and Watawata) were synonymized with the genus Hypostomus, ANSP, Academy of Natural Sciences, Philadelphia; AUM, Au- which was then considered to be monophyletic, though sup- burn University Museum, Auburn; MCP, Museu de Ciências ported by relatively few synapomorphies, none of which is e Tecnologia, Porto Alegre; MNRJ, Museu Nacional, Rio de exclusive. Armbruster’s (2004) conclusions on Hypostomini Janeiro; MZUSP, Museu de Zoologia da Universidade de São are not, however, consensual: Montoya-Burgos et al. (2002) Paulo, São Paulo; UFBA, Universidade Federal da Bahia, Sal- presented molecular evidence for a paraphyletic Hypostomus, vador. based on which Weber (2003) recognized as valid the genera Aphanotolurus, Isorineloricaria, plus the genus Squaliforma Hypostomus chrysostiktos, new species for Hypostomus emarginatus and related species. Figs. 1 and 2 In the last few years, increasing colleting efforts in the rio Paraguaçu basin, a coastal drainage of eastern Brazil, have Pterygoplichthys sp.: Higuchi, Britski & Garavello, 1990: 225 revealed a rich, endemic ichthyofauna (Higuchi et al., 1990; [misidentification; Bahia, rio Paraguaçu at the area de Pinna, 1992; Campanario & de Pinna, 2000; Lima & Gerhard, currently under Pedra do Cavalo dam]. 2001; Zanata & Akama, 2004; Malabarba et al., 2004; Britto et al., 2005). To that list we add below a new armored catfish of Holotype. MZUSP 88157, 222.4 mm SL, Brasil, Bahia, Iaçu, rio the family Loricariidae that is also apparently endemic to the Paraguaçu, Fazenda Santo Antonio at 10 km from Vila São Vicente, 12°30’54.1”S 39°22’53.9”W, 134 m elevation, 7 Jun 2005; A. M. rio Paraguaçu basin. Zanata, J. L. O. Birindelli, O. T. Oyakawa, M. P. Geraldes, P. C. A. Cardoso & P. Moura. Material and Methods Paratypes. All from Brazil, Bahia, rio Paraguaçu basin: ANSP 185374, 1, 166.6 mm SL; MZUSP 88158, 3, 157.9-212.2 mm SL; collected Methodology and terminology for measurements follow with holotype. AUM 45646, 1, 117.0 mm SL; MZUSP 88159, 5, Boeseman (1968), Armbruster & Page (1996), Bockmann & 72.7-223.5 mm SL; UFBA 02786, 5, 112.3-259.7 mm SL; Iaçu, rio Ribeiro (2003), and Hollanda Carvalho & Weber (2004), with Paraguaçu, Fazenda Os Touros, 12°41’10.6”S 40°07’4.7”W, 143 m the inclusion of the following measurements: anal-fin spine elevation, 8 Jun 2005; A. M. Zanata et al.. MCP 41000, 1, 101.0 mm length; anal-fin base length; body depth at dorsal-fin origin; SL; MZUSP 91635, 3, 96.5-149.5 mm SL; Itaetê, rio Una, 12°56’08”S 41°03’54”, 4 Dez 2005; A. M. Zanata et al. MNRJ 22780, 2, 50.4- mouth width, taken at the level of maxillary-barbels insertion; 147.3 mm SL; Palmeiras, rio Santo Antônio (Bahema), 12°25’16.6”S premaxillary-ramus length; and maxillary-barbel length, taken 41°22’20.9”W, 8 Nov 1999; A. Clistenes. MNRJ 22781, 1, 151.6 from free inner portion of barbel. Plate counts and mm SL; Palmeiras, rio Santo Antônio (Camelo), 12°25’36.7”S nomenclature follow schemes of serial homology proposed 41°25’49.1” W, 8 Nov 1999; A. Clistenes. MZUSP 49262, 1, 45.5 by Schaefer (1997), with modifications by Oyakawa et al. mm SL; MZUSP 84231, 3 (1 c&s), 29.0-33.1 mm SL; Itaetê, Olho (2005). The following new counts were included: paired dorsal d´água do Almerindo, tributary of rio Una, Jun 1993; A. M. Zanata et plates between end of the dorsal-fin base and adipose-fin al. MZUSP 88161, 2, 68.4-104.5 mm SL; UFBA 02788, 2, 79.4-93.4 base; ventral plates between end of anal-fin base and lower mm SL; rio Ferro Doido at Cachoeira Domingos Lopez, rio Jacuípe caudal-fin spine, not including plate at base of rays. Standard basin, 11°33’32.1”S 40°54’20.3”W, 662 m elevation, 11 Jun 2005; A. M. Zanata et al. MZUSP 88165, 2 (1 c&s), 117.5-122.7 mm SL; length (SL) is expressed in mm and all other measurements MZUSP 88617, 2 (1 c&s), 114.0-194.8 mm SL; UFBA 02031, 3, are expressed as percentage of standard length, except 60.3-82.3 mm SL; UFBA 02040, 23, 78.2-163.8 mm SL; UFBA subunits of head, which are expressed as percentage of head 02785, 6, 129.4-222.8 mm SL; Cachoeira, rio Paraguaçu (area cur- length. Measurements and counts were taken on the left side rently under Pedra do Cavalo dam), 15 Oct 1980; V. Almeida et al.. of the specimens, whenever possible. Osteological MZUSP 88173, 1, 117.9 mm SL; UFBA 02039, 2, 115.2-133.4 mm examination, counts of branchiostegal rays, vertebrae, and SL; Lençóis, rio Santo Antônio de Licurioba, 5 Feb 2001; L. Panelli. data on position of dorsal, pelvic and anal fins in relation to UFBA 02030, 2, 100.4-153.9 mm SL; Cachoeira, rio Paraguaçu (area vertebral column were examined only in cleared and stained currently under Pedra do Cavalo dam), 13 Aug 1980; V.