Pseudotocinclus tietensis ( Ihering, 1907 )

Takako, Adriana Kazue, Oliveira, Claudio & Oyakawa, Osvaldo Takeshi, 2005, Revision of the genus Pseudotocinclus (Siluriformes: Loricariidae: Hypoptopomatinae), with descriptions of two new species, Neotropical Ichthyology 3 (4), pp. 499-508 : 501-503

Pseudotocinclus tietensis ( Ihering, 1907) Fig. 2

Otocinclus (Microlepidogaster) tietensis Ihering, 1907: 26- 27 (type-locality: rio Tietê, São Paulo). - Eigenmann, 1910: 413 (reference). - Gosline, 1945: 100 (reference). - Fowler, 1954: 131 (reference). - Britski, 1969: 200 (catalogue of types).

Pseudotocinclus tietensis . - Britski & Garavello, 1984: 226 (redescription). - Burgess, 1989: 439 (list of the species of Loricariidae ). - Montoya-Burgos et al., 1998: 363-374 (phylogenetic relationships of the Loricariidae ). - Isbrücker, 2001: 32 (reference). - Schaefer, 2003: 327 (check list).

Microlepidogaster tietensis . - Miranda Ribeiro, 1911: 89, 422 (copy of description).

Pseudotocinclus intermedius Nichols, 1919: 534 (type-locality: Campo Grande, Santo André, São Paulo). - Gosline, 1945: 99 (catalogue). - Fowler, 1954: 134 (reference). - Isbrücker, 1980: 86 (classification and catalogue of Loricariidae ). – Schaefer, 2003: 327 (check list; as synonym of P. tietensis ; type locality erroneously assigned as Campo Grande, Mato Grosso).

Material examined. Brazil, São Paulo: MZUSP 714 (1), 44.0 mm SL, Alto da Serra , near Paranapiacaba, Santo André (Paratype of Pseudotocinclus intermedius ) . MZUSP 1003 (1), 46.5 mm SL, Perus (Paratype of Pseudotocinclus intermedius ). MZUSP 35235 (8), 37.6-50.3 mm SL, small creek near Paranapiacaba, Santo André, Excursão MZUSP, Nov 1985 . MZUSP 42389 (29, 2 c&s), 31.2- 58.7 mm SL, same locality as above. LIRP 5283 (6), 39.3-58.1 mm SL, same locality as above, 31 Oct 1988 . MZUSP 42390 (4), 49.4- 57.2 mm SL, a small creek close to the above locality, 31 Oct 1988 . MCP 37522 (4), 47.5-60.8 mm SL, a small creek close to the above locality, 31 Oct 1988 . MZUSP 42330 (6), 47.6-55.9 mm SL, Itabim, a tributary of the rio Juqueri Mirim , Companhia Melhoramentos de São Paulo, rio Tietê basin, Caieiras, 22 Nov 1990 . LBP 696 (18), 47.7-56.5 mm SL, a tributary of rio Grande, rio Paranapiacaba, rio Tietê basin, approximately 23 o 46’S, 46 o 19’W, Santo André, 10 Mar 2000 . MNRJ 28391 (5), 54.6-57.5 mm SL, rio Paraitinga, rio Tietê basin, Salesópolis, 23 o 31.5’S, 45 o 47.5’W, 24 Jan 2001 . MNRJ 28391 (6), 30.8-67.2 mm SL, rio Paraitinga, rio Tietê basin, Salesópolis, 23 o 31.5’S, 45 o 47.5’W, 24 Jan 2001 . MZUSP 48127 (2 c&s), no data. MZUSP 85905 (4), 29.6-35.7 mm SL, rio Lavras, tributary of the rio Tietê , Embu Guaçu, 23 o 54’46"S, 46 o 55’12"W, 30 Aug 2004 . DZSJRP 6606 (3), 21.2-31.5 mm SL, rio Itatinga, near Visitors Center, Reserva Particular do Patrimônio Natural Parque das Neblinas, Bertioga, 23 o 44’59"S, 46 o 09’51"W, 27 May 2004 . MZUSP 87766 (23), 32.1-57.6 mm SL, creek at the Núcleo Barrocada, Parque Estadual da Cantareira , São Paulo, 23 o 23’09"S, 46 o 33’56"W, 07 July 2005 .

Diagnosis. The presence of a small naked area on the snout tip distinguishes Pseudotocinclus tietensis from P. parahybae and P. juquiae , which have the snout tip covered with small platelets. In addition, Pseudotocinclus tietensis has four transverse dark-brown bands on the dorsal region of the body that coalesce with a midlateral stripe, rather than three in its congeners.

Description. Morphometric and meristic data given in Table 1; examined specimens 37.6-58.1 mm SL; dorsal profile of head convex from snout tip to end of parieto-supraoccipital; dorsal profile of body convex from snout tip to dorsal-fin origin; relatively straight and gently descending from dorsal-fin origin to end of caudal peduncle; ventral profile of body straight from snout tip to scapular bridge; convex more posteriorly to origin of anal-fin, and straight along caudal peduncle. Head plates with small odontodes and comparatively smooth; median region of snout with low crest that terminates between nares; another low crest on either side of snout that continues as low crest on dorsal region of orbit; orbital ring not as prominent or conspicuous as in P. juquiae ; parieto-supraoccipital and paired compound pterotic bones with low crest, comparatively larger in P. parahybae , but smaller in P. juquiae . Parieto-supraoccipital bordered by three to six plates. Interorbital region flattened. Anterior orbital margin positioned approximately midway between snout tip and pterotic posterior process; distance between ventral orbit margin and ventral surface of head slightly greater than twice orbit length; snout tip with small naked area; narrow area of upper lip near snout tip, with scattered platelets having odontodes; length of maxillary barbel comparatively greater than in P. parahybae . Sphenotic ventral margin contributing to orbit, and contacting frontal anteriorly and compound pterotic posteriorly; as consequence, infraorbital canals of cephalic laterosensory system enter infraorbital series via sphenotic; infraorbital 4 not expanded ventrally and not in contact with preopercle; space between these two bones filled with several small plates. Mid-dorsal series of plates interrupted, only five plates counting from dorsal-fin origin. Plates of median series expanded dorsally and contacting dorsal series of plates. Plates in median (lateral) series with lateral system pores. Third lateral line plate reduced in size, as two anterior plates, positioned posterior to rib of sixth centrum, and not covering distal tip of rib. First five plates of midventral series comparatively small; inferior tip of first plate contacting tip of coracoid ventrolateral process, and fifth plate only touching lateropterygium tip; unplated area dorsal to pelvic fin comparatively larger; first three plates of ventral series comparatively smaller with tips touching external side of basipterygium posterior process. Coracoid with small ventrolateral portion exposed and covered with odontodes implanted directly on bone. Abdomen covered with relatively large and roughly rounded platelets not in contact with one another, leaving naked area of skin exposed; region between pelvic fin and urogenital pore scarcely covered with platelets. Dorsal-fin origin situated slightly posterior to vertical line through pelvic-fin origin; posterior margin of dorsal fin straight. When depressed, tip of first unbranched dorsal-fin ray reaching vertical line through origin of third ray of anal-fin; first unbranched dorsal-fin ray width greater than width of second unbranched dorsal-fin ray base. Pectoral-fin unbranched ray covered with small odontodes; its tip extending past pelvic-fin origin; length of first branched pectoral-fin ray equal to unbranched pectoral-fin ray. Distal margin of pelvic fin slightly rounded; its tip almost reaching anal-fin origin. Internal and external anterior processes of pelvic-fin basipterygia fused into compact bone. Basal lamina of first proximal radial of anal fin covered with skin and five or six small irregular plates not visible externally. Hemal spine of vertebra 20 bifurcated; caudal fin with four dorsal procurrent rays and three ventral procurrent rays.

Color in alcohol. Light brown ground coloration on dorsal and lateral regions of body; head, ventral region, and belly grayish, with numerous dark brown melanophores distributed on surface; dark brown midlateral stripe extending from snout to end of caudal peduncle; stripe almost equal in width in entire length. Four transverse dark-brown bands on dorsal region of body coalesced with midlateral stripe, first at dorsal-fin origin, second just behind dorsal-fin base, third in middle of caudal peduncle, and last near posterior end of caudal peduncle; second band broader than others. Unbranched and branched caudal-fin rays and interradial membranes sometimes showing uniformly dark brown ground coloration as in P. parahybae or showing color pattern similar to that of P. juquiae ; unbranched rays of other fins with four to five dark brown bands; branched rays with bands of melanophores irregularly arranged; interradial membranes hyaline.

Distribution and habitat. This species occurs in many tributaries of the upper Tietê basin ( Fig. 1 ). It is found both in small creeks and medium size rivers such as the rio Paraitinga, a tributary of the rio Tietê, where it lives grazing on semisubmersed overhanging plants; in the rio Grande, a small sized river which drains to the Billings Dam near Vila de Paranapiacaba, Santo André. This species can be found attached to the grass along the river margin and in the middle of the river among rocks and pieces of wood in fast current water. In the rio Grande, Pseudotocinclus tietensis coexists syntopically with Glandulocauda melanogenys , Hyphessobrycon reticulatus , Hollandichthys multifasciatus , Astyanax aff. scabripinnis , Characidium oiticicai , Hisonotus depressicauda , Trichomycterus sp. , Gymnotus pantherinus , and Phalloceros caudimaculatus . Pseudotocinclus tietensis also occur with Hyphessobrycon anisitsi , Astyanax altiparanae , Hoplias malabaricus , Phalloceros caudimaculatus , Geophagus brasiliensis , Trichomycterus sp. , and Taunaya bifasciata , in the conservation unit of Parque Estadual da Cantareira, a remnant of the Atlantic Forest inside the city of São Paulo.

Figures

Fig. 2. Pseudotocinclus tietensis, MZUSP 35235, 50.3 mm SL; small creek near Paranapiacaba, Santo André, São Paulo, Brazil.

Fig. 1. Southern part of São Paulo, Brazil, showing the geographic distribution of P. tietensis (squares), P. juquiae (triangles), and P. parahybae (circle). Some symbols represent more than one lot or locality. Open symbols = type locality. The precise type locality of P. tietensis is not known. 1- rio Paraíba do Sul basin; 2 - rio Tietê basin; 3 - rio Ribeira de Iguape basin.