Pareiorhaphis ruschii, Pereira & A. & Reis, 2012

Pereira, Edson H. L., A., Pablo Lehmann & Reis, Roberto E., 2012, A new species of the Neoplecostomine catfish Pareiorhaphis (Siluriformes: Loricariidae) from the Coastal basins of Espírito Santo, Eastern Brazil, Neotropical Ichthyology 10 (3), pp. 539-546 : 540-544

Pareiorhaphis ruschii , new species

Fig. 1

Holotype. MCP 46640 , male, 84.7 mm SL, Brazil, Espírito Santo State, Santa Teresa Municipality, córrego Lombardia ca. 1 km NE of the Reserva Biológica Augusto Ruschi , tributary to rio Piraquê-Açu , 19°52’26” S 40°32’08” W, 23 Jan 2010, R. E. Reis, E. H. L. Pereira & P. Lehmann.

Paratypes. Brazil: Espírito Santo, Santa Teresa, rio Piraquê-Açu drainage: MCP 44807 , 25 , 33.6-96.7 mm SL (14, 51.7-96.7 mm SL) + 2 c&s, 53.1-61.8 mm SL, collected with the holotype. MCP 41867 , 5 , 34.8-90.5 mm SL (3, 57.9-90.5 mm SL + 1 c& s 73.4 mm SL), córrego Lombardia , near the Reserva Biológica Augusto Ruschi , 9 Mar 2005, R. L. Teixeira. MCP 27678 , 3 , 49.6-64.2 mm SL (1, 64.2 mm SL), MCP 41814 , 3 , 53.2-65.2 mm SL (2, 61.1-65.2 mm SL), and MBML 3374, 4, 51.6-74.4 mm SL (3, 64.4-74.4 mm SL), córrego Lombardia, near the Reserva Biológica Augusto Ruschi, 19°52’42” S 40°32’15” W, 12 Feb 2001, R. L. Teixeira. MCP 41790 , 4 , 52.1-80.5 mm SL (3, 67.4-80.5 mm SL), córrego Lombardia, near the Reserva Biológica Augusto Ruschi, 15 Sep 2003, R. L. Teixeira. MCP 41871 , 3 , 23.5-75.7 mm SL (1, 75.7 mm SL), córrego Lombardia, near the Reserva Biológica Augusto Ruschi, 19°52’30” S 40°32’10” W, 6 Oct 2003, R. L. Teixeira. MZUSP 23813 (1, 63.8 mm SL), córrego Lombardia, 2 Apr 1969, MZUSP Expedition .

Additional non-type specimens. Brazil, Espírito Santo, Santa Teresa, rio Reis Magos drainage: MCP 29508 , 4 , 31.4-87.7 mm SL, rio da Penha at Sítio do Rubinho , rio Timbuí basin, 24 Oct 2001, R. L. Teixeira. MCP 34411 , 3 , 34.4-76.7 mm SL, córrego Valão de São Lourenço , rio Timbuí basin, 24 Jul 2002, R. L. Teixeira. MCP 41811 , 1 , 98.8 mm SL, rio Santo Antônio da Penha at Sítio Águas Claras, rio Timbuí basin, Dec 2004, R. M. Pizziolo. MCP 27320 , 1 , 40.4 mm SL, córrego Santo Antônio, 12 Oct 2000, R. L. Teixeira. MCP 41783 , 1 , 45.4 mm SL, rio Timbuí at Penha, 1997, R. L. Teixeira .

Diagnosis. Pareiorhaphis ruschii differs from all congeners except P. azygolechis , in having the lower lip margin densely fringed ( Fig. 1 ; vs. smooth or just slightly fringed). The new species can be further distinguished from all other Pareiorhaphis species but P. garbei and P. azygolechis in having a series of six to ten (usually seven to nine) small median, preadipose azygous plates, forming a low postdorsal ridge between the dorsal and the adipose fins ( Fig. 2 , vs. none to five preadipose plates). Pareiorhaphis ruschii is further distinguished from all remaining species except P. calmoni , P. bahianus , P. nudulus , P. hypselurus , and P. stomias by having the pectoral-fin spine very long and straight, reaching the distal third of the pelvic fin when adpressed in adult males ( Fig. 1 , vs. spine short and curved and maximally reaching half of the pelvic-fin length). It is also differentiated from most species, except P. eurycephalus , P. hypselurus , P. stomias , and P. stephanus by having the hypural plate asymmetrical with the lower lobe longer than the upper ( Fig. 3 , vs. hypural plate approximately symmetrical).

Description. Counts and proportional measurements in Table 1. Small to medium-sized loricariid with standard length of measured specimens 51.7-96.7 mm SL. Body stout, moderately depressed. Greatest body width at cleithrum, progressively tapering to end of caudal peduncle. Dorsal profile of body slightly convex, from snout tip to dorsal-fin origin and almost straight from that point to end of adipose fin, then slightly concave to caudal fin.Greatest body depth at dorsal-fin origin. Least body depth at shallowest part of caudal peduncle. Trunk and caudal peduncle mostly oval in cross-section, flattened ventrally and more compressed caudally.Lateral-line canal in median series complete, pored tube visible from compound pterotic to caudal-fin base.Ventral profile almost straight between snout tip and pelvic girdle, slightly elevating posteriorly along anal-fin base, almost straight along caudal peduncle.Dorsal surface of body covered by plates except for narrow naked area around dorsal-fin base. Predorsal plates arranged in two to four series of pairs in some specimens, or without any noticeable arrangement. Five lateral rows of dermal plates covering body, not forming keels; mid-dorsal and mid-ventral series of lateral plates incomplete, terminating 3-4 plates before caudal fin.Ventral surface of head, portion from pelvic-fin insertion to anal-fin origin, and region around urogenital opening totally naked. Abdomen almost completely naked, except for small embedded platelets or few odontodes on each side just posterior to gill opening, visible externally, sometimes absent in specimens smaller than 50.0 mm SL.

Head broad and moderately depressed. Outline of head round in dorsal view; adult males more slender anteriorly. Interorbital space straight or slightly concave. Three weakly elevated ridges between orbits and snout tip. Outer ridges from middle of snout to upper margins of orbits slightly more prominent. Ridges ornamented with many short hypertrophied odontodes directed upward in adult males. Odontodes straight, conical and pointed distally, densely covering these ridges and making this area somewhat hispid ( Fig. 4 ). Snout convex in lateral profile; snout tip with small ovoid area of naked skin. Adult males with slender soft fleshy lobes extending along lateral portion of head. Soft fleshy area ornamented with hypertrophied odontodes; larger odontodes bent anteriorly ( Fig. 4 ). Eye small, dorsolaterally placed; orbital diameter 12.2- 16.1% HL. Iris operculum absent or very small. Nares ovoid, slightly longer than wide, positioned much closer to anterior margin of orbit than to snout tip. Lips well developed, occupying most of ventral surface of head. Lower lip wide and long but not reaching pectoral girdle, upper lip narrow. Lower lip densely covered by minute papillae. Papillae surrounded by small naked areas, decreasing in size towards edge but then increasing again to become slightly larger than those in central region of lip. Margin of lower lip densely fringed. Maxillary barbel short and united to lip by membrane basally, free distally. Teeth series in both premaxillae and dentaries with mesial ends slightly curved inwards. Teeth slender, asymmetrically bifid, medial cusp slightly curved inwards. Lateral cusp small and pointed, reaching or almost reaching half-length of medial cusp.

Dorsal fin originating on vertical line passing through pelvic-fin origin. Dorsal fin short, usually not contacting preadipose azygous plates when adpressed, sometimes contacting in adult males. Nuchal plate exposed, not covered by skin. Dorsal-fin spinelet present but dorsal-fin locking mechanism nonfunctional. Dorsal-fin spinelet transversely oval-shaped, as wide or slightly wider than base of dorsal-fin spine. Dorsal-fin spine moderately flexible, followed by seven branched rays.Adipose fin with well-ossified leading spine bearing odontodes.Adipose-fin membrane short or extended slightly beyond adipose-fin spine.Adipose fin preceded by six to ten (usually seven to nine) median preadipose azygous plates. Pectoral-fin origin situated more dorsally than pelvic-fin origin.Pectoral fin moderate in size, with spine distinctly straight and flattened, covered by minute odontodes in females, immature males and juveniles.Adult males with pectoral-fin spine very long and straight, tip reaching beyond half length of pelvic fin when adpressed; broadening from insertion to tip, bearing few straight, short hypertrophied odontodes on entire outer face. Pectoral fin with six branched rays, first and second as long as spine. Subsequent branched rays decrease gradually in size, last ray half length of first one. Posterior margin of pectoral fin straight, surpassing mid-length of pelvic fin when adpressed. Pelvic fin with one unbranched and five branched rays, not reaching or just reaching to origin of anal fin when adpressed. Pelvic-fin unbranched ray depressed, covered with minute odontodes ventrally and laterally. Dermal flap on its dorsal surface present and well developed, extending to ray tip in adult males; absent in females.Anal fin long with one unbranched and five branched rays; passing vertical at adipose-fin origin when adpressed. Caudal fin forked or slightly concave; upper and lower lobes approximately equal in size, or lower lobe slightly longer than upper; 14 branched rays. Upper caudal-fin lobe with six and lower lobe with four or five plate-like procurrent rays, posteriormost elongate. Odontodes on principal and procurrent rays small and irregularly arranged. Hypural plate asymmetrical with lower lobe longer than upper.Total vertebral centra 29-30.

yellow (some juveniles) or with small dark grey spots scattered on lateral portion of abdomen. Ventral portion of caudal peduncle dusky. Some specimens with numerous small dark spots. Mid-ventral line on caudal peduncle unpigmented, forming thin ventral light stripe limited by dusky lateral portions of caudal peduncle. Paired and dorsal fins with 3-4 transverse irregular dark bars. Caudal fin with five and anal fin with 2-3 Color in alcohol. Overall background color of dorsal and lateral surface of head and trunk dark gray or sometimes light to dark brown; yellowish or whitish pale ventrally. Dorsum and part of flanks covered by irregularly scattered darker brown blotches. Blotches usually arranged in four inconspicuous transverse saddles: at predorsal and anterior dorsal-fin base, posterior portion of dorsal-fin base, at preadipose and anterior adipose fin, and between adipose and caudal fin. Lips yellowish. Ventral surface of head and abdomen either completely whitish or pale transverse irregular dark bars. One yellowish blotch on both upper and lowermost caudal fin rays in some specimens.

Distribution. Known from the upper reaches of the rio Piraquê-Açu and rio Reis Magos in Espírito Santo State, Brazil ( Fig. 5 ). Only specimens from the rio Piraquê-Açu basin were included as paratypes in order to maintain the entire type series from a single river basin.

Habitat and ecological notes. The rio Reis Magos and rio Piraquê-Açu are both costal basins of the Espírito Santo State of Brazil. The headwaters of the córrego Lombardia, where most specimens of Pareiorhaphis ruschii were collected, is a shallow creek (0.5 m depth and approximately 4 to 5 m wide) that crosses theAugusto Ruschi Biologic Reserve. The type material was collected immediately downstream from the reserve limit, where the river was still well preserved.A few hundred meters downstream there are Eucalyptus plantations and the river is highly impacted.

Sexual dimorphism. Mature males possess the remarkable morphological modifications already known to occur in other Pareiorhaphis species, a skin fold on the dorsal surface of the unbranched pelvic-fin ray, a thickened pectoral-fin spine, fleshy lobes on the lateral margins of head, and hypertrophied odontodes emerging from those fleshy lobes and on the pectoral-fin rays. When compared to males, females posses an enlarged, swollen urogenital opening, while males have a small and pointed urogenital papilla.

Etymology. Species name is given in honor of the late eminent Brazilian naturalist Augusto Ruschi in recognition for his outstanding contributions to the knowledge of Atlantic Forest hummingbirds and his unweary efforts to create the conservation area Reserva Biológica Augusto Ruschi, where now Pareiorhaphis ruschii is preserved.

Figures

Fig. 1. Pareiorhaphis ruschii, MCP 46640, holotype, 84.7 mm SL, male, Brazil, Espírito Santo State, Santa Teresa Municipality, córrego Lombardia ca. 1 km NE of the Reserva BiológicaAugusto Ruschi, tributary to rio Piraquê-Açu, 19°52’26”S 40°32’08”W.

Fig. 2. Pareiorhaphis ruschii, MCP 44807, paratype, 53.1 mm SL. Postdorsal trunk, dorsal view. Odontodes omitted. AF, Adipose fin; PAP, Preadipose azygous plates.Scale bar = 5 mm.

Fig. 3. Skeleton of the caudal fin, left side, lateral view. a - Pareiorhaphis azygolechis, MCP 21663, paratype, 68.9 mm SL; b - Pareiorhaphis ruschii MCP 44807, paratype, 61.8 mm SL. EU, Epural; HYP, Hypural; UN, Uroneural; HPP, Hypurapohysis; PH, Parypural; V, Vertebra.Scale bar = 2 mm.

Fig. 4. Pareiorhaphis ruschii,MCP 41811, 98.8 mmSL.Lateral and dorsal views of the head showing development and orientation of hyperthrophied odontodes.

Fig. 5. Distribution of Pareirhaphis ruschii in eastern Brazil. 1, rio Doce. 2, rio Piraquê-Açu. 3, rio Reis Magos. Each dot covers more than one lot or locality. Open symbol is typelocality.