Parotocinclus arandai, a new species of hypoptopomatine catfish (Siluriformes: Loricariidae) from the upper rios Jucuruçu and Buranhém, States of Bahia and Minas Gerais, Brazil

Parotocinclus arandai, new species of the hypoptopomatine catfish, is described from small creeks in the upper rios Jucuruçu and Buranhém basins, at the border of Brazilian States of Bahia and Minas Gerais. Parotocinclus arandai is distinguished from all congeners from the Atlantic coastal basins of southeastern and eastern Brazil, except Parotocinclus bahiensis, by having the branched rays and interradial membranes of the pectoral and pelvic fins unpigmented in ventral view. The new species is distinguished from most Parotocinclus species, by having a small eye, 14.8-19.3 mm HL (except P. maculicauda and P. planicauda) and by the presence of a tuft of hypertrophied odontodes on the supraoccipital (except P. cristatus and P. cesarpintoi). Parotocinclus arandai is further distinguished by having an abdomen extensively naked, with a mosaic of few rounded platelets of irregular size and distributed over the pre-anal region (except P. bahiensis, P. minutus, P. spilosoma, P. cearensis, P. cesarpintoi and P. prata). A detailed comparison with congeners on eastern Brazil hydrographical region is provided, and information on the species habitat is given.


Introduction
The Hypoptopomatinae is a monophyletic subfamily within the Loricariidae comprised of 19 genera with more than 80 species of armored catfishes called Cascudinhos (Carvalho et al., 2008). The monophyly of the genus Parotocinclus Eigenmann & Eigenmann has been controversial. Schaefer (1991) recognized Parotocinclus as monophyletic, considering the following characters: a robust short crest for the adductor musculature, a large first dorsal-fin spinelet, and a lateral line interrupted, terminating in two or four plates preceding the last lateral plate. In the same paper, Parotocinclus was regarded as the sister group of Schizolecis, in a clade also including Otothyris plus Pseudotothyris. In the phylogenetic study of  Parotocinclus occupies a more basal position within the tribe Otothyrini. According to a parsimony analysis of phylogenetic relationships, Parotocinclus was recognized as a polyphyletic assemblage (Gauger & Buckup, 2005), with species suggested to be members of undescribed taxa. Lehmann (2006), in the most recent hypothesis of Hypotopomatinae relationships, based on 169 characters of osteology and external morphology and 114 terminal loricariid taxa, found no evidence to support the monophyly of the tribe Otothyrini, and recognized Parotocinclus as a highly paraphyletic assemblage of species.
Since Garavello's (1977) revision of the genus, eleven new Parotocinclus species have been described. Currently the genus is composed of 23 species (Table 1). However, a new phylogeny of the Loricariidae in progress (P. Lehmann A. & R. E. Reis) provides more information to estimate the phylogenetic relationships, the biodiversity of Parotocinclus, and therefore to rediagnose the subfamily Hypoptopomatinae. The goal of the present paper is to describe a new species of Parotocinclus, and provide a comparison with congeners in the Atlantic coastal basins of eastern Brazil.

Material and Methods
Straight-line measurements were taken point to point under a stereomicroscope with a Mitutoyo digital caliper, and recorded to tenths of a millimeter. Measurements followed Boeseman (1968: fig. 5) and Britski & Garavello (1984). Standard length is expressed in mm. All other measurements are expressed as percents of standard length, except subunits of the head, which are expressed as percents of head length.
Tooth counts were performed separately for left and right Species Distribution 1 P. amazonensis Garavello, 1977 rio Amazonas basin 2 P. aripuanensis Garavello, 1988 rio Aripuanã basin 3 P. bahiensis (Miranda Ribeiro, 1918) Garavello, 1977 rio Almada basin and coastal rivers near Ilhéus, southern Bahia State 10 P. doceanus (Miranda Ribeiro, 1918) rio Doce basin, Espírito Santo State 11 P. eppleyi Schaefer & Provenzano, 1993 upper and middle rio Orinoco basin 12 P. haroldoi Garavello, 1988 rio Sanharó, Piauí State 13 P. jimi Garavello, 1977 rio de Contas basin, southern Bahia State 14 P. jumbo Britski & Garavello, 2002 rio Paraíba do norte basin and coastal rivers in Alagoas, Ceará, Paraíba and Pernambuco States 15 P. longirostris Garavello, 1988 rio Amazonas basin 16 P. maculicauda (Steindachner, 1877) coastal rivers at Rio de Janeiro and Espírito Santo States 17 P. minutus Garavello, 1977 rio Vasa-Barris basin, northern Bahia State 18 P. muriaensis Gauger & Buckup, 2005 rio Paraíba do Sul basin, Rio de Janeiro State 19 P. planicauda Garavello & Britski, 2003 rio Doce basin, Espírito Santo State 20 P. polyochrus Schaefer, 1988 rio Negro drainage, Amazon basin 21 P. prata Ribeiro, Melo & Pereira, 2002upper rio São Francisco 22 P. spilosoma (Fowler, 1941 rio Paraíba do Norte basin, Paraíba State 23 P. spilurus (Fowler, 1941) rio Salgado, Ceará State Table 1. Summary of the distribution of Parotocinclus species. dentaries and premaxillae. Bilateral average counts were determined as the mean between the left and the right side for each specimen. Dermal plate counts are: lateral plate seriesnumber of dermal bones along the lateral line, counted from the posterior process of pterotic-supracleithrum to posterior hypural margin; lateral to dorsal-fin base plates -number of lateral dorsal dermal bones along the dorsal-fin base; plates between dorsal and adipose fins -number of dermal bones in dorsal series between the last dorsal-fin branched ray insertion and the origin of the adipose-fin spine; plates between adipose and caudal fins -number of dermal bones in the dorsal series between the adipose membrane and posterior hypural margin; plates lateral to anal-fin base -number of dermal bones in ventral series along the anal-fin base; plates between anal and caudal fins -number of dermal bones in ventral series between the last anal-fin branched ray insertion and posterior hypural margin; preadipose plates -number of azygous plates preceding the adipose-fin spine. Fin-ray counts included the number of unbranched and branched rays in pectoral, ventral and caudal fins. Osteological terminology followed Schaefer (1997) and was studied in cleared and stained specimens (c&s), following the procedures of Taylor & Van Dyke (1985). Institutional abbreviations followed Leviton et al. (1985), with the exception of MBML Diagnosis. Parotocinclus arandai is distinguished from all other Parotocinclus species of the Guyana Shield, Amazonas and Orinoco basin (except P. collinsae) by the absence of a triangular patch of dark pigmentation at the anterior dorsalfin base. The new species differs from the P. collinsae by the absence of the accessory teeth on the premaxilla and dentary. Parotocinclus arandai differs from all congeners of the Atlantic coastal basins of southeastern and eastern Brazil by having the branched rays and interradial membranes of the pectoral and pelvic fins unpigmented in ventral view; the rostral plate not exposed ventrally (except P. bahiensis, P. spilurus and P. prata). The new species is distinguished from most Parotocinclus species, except P. cristatus and P. cesarpintoi, by the presence of a tuft of hypertrophied odontodes on the supraoccipital; and by the extensively naked abdomen in adults, with a mosaic of few rounded platelets of irregular size and distributed over the pre-anal region (except P. bahiensis, P. minutus, P. spilosoma, P. cearensis, P. cesarpintoi, and P. prata).
Description. Morphometric and meristic data presented in Table 2. Body moderately short, robust, head and anterior trunk elevated. Dorsal profile of head from snout tip to anterior orbital rim arched; straight between supracleitrum and dorsalfin origin; slightly concave from near adipose-fin base to caudal-fin base. Ventral profile from snout to pectoral-fin base concave, straight from pectoral-fin base to anus and then slightly concave to caudal-fin base. Snout rounded in dorsal profile, rostrum convex; trunk ovoid in cross section anteriorly, progressing to elliptical to triangular posteriorly. Cross-section of caudal peduncle compressed laterally. Eyes small (14.8-19.3% HL) and superior. Dorsal fin when depressed reaching to vertical through origin of anal fin. Pectoral fin reaching to just beyond pelvic-fin origin; pelvic fin reaching beyond anus, ending just anterior to anal-fin origin.
Head and trunk usually without keels; odontodes evenly distributed and regularly arranged on head and body; small tuft of hypertrophied odontodes present, on posterior portion of supraoccipital. Premaxillary teeth 21-28; dentary teeth 20-30. Oral disk ovoid; lower lip with prominent papillae, variable in size; upper lip about half depth of lower lip. Short maxillary barbel present (5.3-6.5% SL). Infraorbitals five, two anteriormost larger than posterior ones. Infraorbital 3 in contact with prefrontal and second infraorbital, forming anterior corner of orbit. Infraorbital 4 with concave dorsal margin, forming ventral portion of orbital rim. Infraorbital 5 smallest, forming posterior orbital rim. Supraorbital crest conspicuous.
Posterior margin of supraoccipital followed by three plates on each side, medial pair sometimes fused together in one plate, followed by one pair and one azygous predorsal plate just anterior to dorsal-fin origin. Rostral margin with three postrostral bony plates between unpaired rostral plates on tip of snout. Rostral plate and subsequent postrostral plates around snout with slight ventral curvature. Dorsal rostral plate not exposed ventrally. First dorsal-fin spinelet small; spine of adipose fin prominent; adipose-fin origin vertically crossing at about end of adpressed anal-fin. Last anal-fin ray lacking posterior membrane. Abdomen with paired series of 2-4 small, median abdominal area naked, without platelets or with few rounded platelets of irregular size and distribution; region between pelvic fins with mosaic of few platelets, expanding over pre-anal shield region (Fig. 2). A median row of platelets only in large sized specimens (larger than 24 mm SL). Young specimens (less than 24 mm SL) with platelets limited to pre-anal region. Lateral line incomplete with pores visible on first 5 or 6 anterior plates and sporadically along trunk between dorsal fin and caudal peduncle. Intermediate plates without pores 2-5.
Color in alcohol. Irregular narrow dark brown stripe along trunk, between transverse dark bars, interrupted at certain points in some specimens. Ventral surface of head and belly whitish. Adipose fin with dark blotch at its base. Four irregular brownish bars on trunk; first one close to dorsal-fin origin, second at end of dorsal-fin base, third at adipose-fin origin, and fourth on caudal peduncle. Pelvic and anal fins with few and sparse chromatophores on dorsal side, not forming bands. Pectoral and pelvic fins with branched rays and interradial membranes unpigmented in ventral view. Caudal-fin base with dark vertical bar. Caudal fin with irregular color pattern, but inconspicuous darkened band always present at middle of each lobe. Ground color in ethanol becomes grayish.
Live coloration. Ground color pale yellow. Predorsal area of body mottled with faint small dark blotches (Fig. 3). Longitudinal discontinuous stripe present along lateral line. Unbranched first ray in both dorsal and pectoral fins with alternate series of white and dark spots aligned, forming bands. Subsequent rays with alternate spots, giving maculate pattern to rays. Caudal-fin rays with dark chromatophores forming bands. Etymology. The specific name arandai honors our ichthyologist colleague Arion Túlio Aranda in recognition of his talent for catching fish and knowledge of their habits. or behavior of attachment to submerged marginal vegetation were reported for different species groups by Garavello (1977) and information on diet is available for P. prata in Ribeiro et al. (2002). During this study specimens were collected in clear, shallow waters, approximately 0.3 m in depth, in moderate flowing sections of the rivers, with a sandy or gravel bottom. Riparian environments were most impacted by agriculture and cattle, and surrounded by mild vegetation and with a few floating meadows.

Discussion
The genus Parotocinclus has been recognized based on a combination of characters, such as the presence of an adipose fin, head not strongly depressed, eyes not visible in ventral view, pectoral arrector fossae opened (at least partially), region of snout surrounding anterior portion of nostrils plated and slightly depressed, head without crests (Schaefer & Provenzano, 1993); and on the presence of a caudal fenestrum anterior to notch between hypurals 2 and 3 . These features are all present in P. arandai.
The paraphyletic nature of Parotocinclus was initially presented by Gauger & Buckup (2005) who reanalyzed the phylogenetic relationships of the Hypoptopomatinae including 31 terminal taxa and based on 45 characters of  and 11 additional characters. In their study nine Parotocinclus species were analyzed, with the following seven recovered as a monophyletic group: P. cearensis, P. cesarpintoi, P. haroldoi, P. bidentatus, P. muriaensis, P. doceanus, and P. maculicauda. Synapomorphies uniting this restricted monophyletic assemblage of Parotocinclus are a mid-dorsal lateral plate series with more than eight plates, extending beyond the dorsal fin to the caudal peduncle; the fourth infraorbital bone with a relatively small ventral lamina; and an adipose-fin (sometimes replaced by one to three unpaired platelets at typical adipose-fin position). The presence of these characters in P. arandai would place it among this monophyletic assemblage recognized as Parotocinclus.
Parotocinclus arandai differs from its congeners in the Atlantic coastal basins of southeastern Brazil, P. bidentatus, P. maculicauda, and P. planicauda in having an extensively naked abdomen (vs. covered with plates) and the presence of a small tuft of hypertrophied odontodes on the supraoccipital (vs. absence). Parotocinclus muriaensis shares with P. arandai a partially exposed pectoral girdle; the new species is distinguished from both P. bidentatus and P. muriaensis by the presence of an adipose fin (vs. absence in P. bidentatus and P. muriaensis) and by the absence of unicuspid teeth behind the series of bicuspid teeth of the dentary and premaxilla (vs. presence). Parotocinclus arandai is further distinguished from P. maculicauda by having four irregular transverse dark bars along the trunk (vs. trunk with a single longitudinal dark stripe along lateral mid-line in P. maculicauda) and caudal fin with scattered chromatophores forming a somewhat striped pattern (vs. lower caudal-fin lobe darkened and upper caudal-fin lobe whitish in P. maculicauda). Parotocinclus arandai is further distinguished from P. planicauda by having 2-4 small plates on lateral series (vs. 5-7 elongated plates on lateral series in P. planicauda) and pectoral girdle partially exposed (vs. completely exposed in P. planicauda).
The new species is morphologically most similar to species in the Atlantic coastal basins of Eastern Brazil. These basins include all river drainages between the rio Vaza Barris, in  Symbols may represent more than one locality Sergipe State, in the north to the rio São Mateus, Espírito Santo State in the south (Fig. 5). These coastal river drainages harbor five Parotocinclus species: P. bahiensis, P. cristatus, P. doceanus, P. jimi, and P. minutus. Parotocinclus arandai differs from all of these species, except P. bahiensis, in having extensive naked areas on the abdomen.
Paratocinclus bahiensis was described as Microlepidogaster bahiensis from northern Bahia by Miranda Ribeiro (1918). The type material was caught by E. Garbe in 1908, and since then no additional material became available in collections. The type material disappeared (Britski, 1969). The recognition of this species as a Parotocinclus was made by Garavello (1977), based on the presence of an adipose fin and on the distributional range of the genus. Parotocinclus bahiensis was collected in Vila Nova, Bahia, (Miranda Ribeiro, 1918), a locality now named Senhor do Bonfim. It is situated on the upper portion of rio Itapicuru, a medium sized river drainage on northern Bahia. The original description is little informative and additional specimens of P. bahiensis were recently caught at the type locality (A. Zanata, comun. pess.), permitting a detailed comparison with P. arandai. Detailed information on P. bahiensis morphology was provided by H. A. Britski (pers. comm.), through a redescription of this illknown Parotocinclus species. A direct comparison between individuals of Parotocinclus bahiensis and P. arandai shows that both species have a similar naked abdomen, with a mosaic of small plates and with only a small portion of the pectoral girdle exposed. Although superficially similar, the two species differ regarding the number of 22-23 lateral plates (vs. 24-25 in P. bahiensis), and the presence of a small tuft of hypertrophied odontodes on supraoccipital (vs. absence in P. bahiensis). They also differ regarding osteological features, as in the new species the second paired rib is articulated to 8 th centrum (vs. 7 th in P. bahiensis) and have 22 vertebrae (vs. 23 in P. bahiensis). There are differences regarding proportional measurements, as a small eye 14.8-19.3% HL in P. arandai (vs. large eye 23.4-26.7% HL in P. bahiensis). The remaining Parotocinclus species from the Atlantic coastal basins of eastern Brazil are morphologically very different from P. arandai, as all of them do possess an abdomen covered with plates and a completely exposed pectoral girdle.
We observed a remarkable pattern of endemism in the fish fauna from the rio São Mateus to the rivers in the extreme south of Bahia, south of the rio Jequitinhonha. Fish species restricted to coastal river drainages between northern Espírito Santo and extreme southern Bahia include Oligosarcus acutirostris, Rachoviscus graciliceps, Mimagoniates sylvicola, Aspidoras virgulatus, Pogonopoma wertheimeri, Pseudauchenipterus affinis, and also Phalloceros ocellatus. Parotocinclus arandai appears to be an addition to this list.