Tatia strigata Soares-Porto, 1995

Tatia strigata Soares-Porto, 1995 View in CoL

Figs. 40-42 View Fig View Fig View Fig

Tatia cf. brunnea View in CoL . Burgess, 1989: 242, pl. 113. [tropical South America].

Tatia strigata Soares-Porto, 1995: 202 View in CoL , fig. 1. [ type locality: igarapé Limãozinho, Maués, Amazonas, Brazil]. Burgess & Finley, 1996:166 [reference]. Soares-Porto, 1998: 333 [citation]. Ferraris, 2003:477 [checklist]. Lasso et al., 2005: 139 [Alto Orinoco, Orinoco]. Ferraris, 2007: 78 [checklist].

Diagnosis. Tatia strigata is the only species of the genus with a completely striped color pattern, bearing whitish elongate longitudinal irregular stripes along lateral sides of body. A unique arrangement of adult male modified anal fin is present, with the second unbranched anal-fin ray with anterior enlarged segments and a notch formed by the reduction of the second and third branched rays ( Soares-Porto, 1995). Tatia strigata is also distinguished from all congeners by a combination of characteristics: four branched pectoral-fin rays; 7 ribs; 29-30 vertebrae; and mature males with upper caudal-fin lobe slightly elongated, same length in females.

Description. Measured specimens 36.5-55.0 mm SL; morphometric data presented in Table 13 View Table 13 . Body slim, head slightly depressed dorso-ventrally. Head large, robust, outline of head in dorsal view somewhat elliptic, broader than long. Trunk from dorsal-fin base to caudal peduncle gradually compressed. Lateral profile of head from snout tip to opercular margin slightly convex until pectoral-fin insertion. Ventral profile of head and abdomen flat. Ventral profile of body gently curved, concave behind anal-fin origin. Head integument thin, cranial roof visible; well-developed adipose eye lid; eye latero-dorsally located in anterior portion of head; mouth terminal, upper lip extended postero-laterally as well-developed fleshy rictal fold; anterior nostril tubular, located on anterior border of snout; posterior nostril large, rounded, limited by small skin flap; transverse distance between anterior nostrils larger than distance between posterior ones. Maxillary barbel short, extending close to posterior tip of postcleithral process, sometimes shorter; mental barbel short, tips not reaching pectoralfin base, arranged in arc along ventral surface of jaw; inner mental barbel about 50.0-60.0% length of outer mentals. Postcleithral process almost reaching vertical through origin of dorsal fin. Caudal peduncle deep, depth about 13.6-14.5% SL.

Rostral border of cranium with mesethmoid as large as long; premaxilla underneath with synchondral articulation; large elliptical cranial fontanel bounded by mesethmoid and frontal ( Fig. 41 View Fig ); nasal ossified with medial flanges partially sutured to lateral margin of mesethmoid; autopalatine tubular, oriented obliquely to longitudinal axis of body; maxilla about the same size as autopalatine; prevomer expanded anteriorly with well developed arrow-shaped lateral processes; jaws of equal size; premaxilla and dentary with three rows of conical teeth. First nuchal plate somewhat pentagonal; second nuchal plate concave along lateral margins; third nuchal plate curved, projected laterally. Epioccipital process very small.

Suspensorium, hyoid arch, branchial skeleton and opercular bones as in generic description. Suprapreopercle present as short canal bone. Six branchiostegal rays articulated with hyoid arch: four with anterior ceratohyal and two with posterior ceratohyal; last one flattened.

Four infraorbital bones in incomplete series. Infraorbital 1 broad, with short ventro-lateral process; remaining infraorbitals thin, reduced to canalicular portions. Infraorbital 2 smallest, close to infraorbital 1, followed by non-ossified portion of canal below eye and by two posterior canal bones much close to sphenotic, forming posterior orbital rim. Lateral line on body with ossified canal bones limited to head.

Dorsal fin I,4-5 (n=10); dorsal-fin spine with 15-20 antrorse serrations along entire anterior margin; posterior margin smooth. Pectoral fin I,4 (n=10), pectoral-fin spine with 17-21 antrorse serrations along anterior margin; 13-15 retrorse serrations along posterior margin; serrations along both margins progressively larger towards spine tip. Pelvic-fin i,5 (n=10); margin rounded. Adipose fin small, origin on vertical through end of anal-fin base.Anal fin iii, 6-7 (n=10); anal-fin pterygiophores in eight rod-like proximal radials and seven cartilaginous distal radials. Caudal fin forked, lobes with rounded tips, 8+9 principal rays, 7-19 upper procurrent, 7-17 lower procurrent rays (n=10). Pleural ribs 7 attached to consecutive vertebrae. Post-Weberian vertebrae 29-30 (n=3).

Color in alcohol. Dorsal surface, dorsal mid-line and lateral parts of body striated with light narrow longitudinal stripes. Dorsal surface of head and nuchal shield dark brown. Lips and anterior nostrils whitish. Ventral parts of head around chin whitish. Paired fins and anal fin hyaline. Adipose fin with dark base and hyaline tip. Caudal fin with dark brown rays and light brown membranes. Burgess (1989: pl. 113) illustrates live aquarium specimen.

Sexual dimorphism. A single adult male with modified anal fin was examined (MCZ 78092). Only young females are available, and genital papilla is not observed. A genital papilla is visible in the single mature male, with a thick skin flap around deferent duct. The anal fin of mature male ( Fig. 42 View Fig ) is strongly modified, with three unbranched and the first two branched rays enlarged and thickened. The first unbranched ray has a rough anterior border and a curved tip ( Fig. 42 View Fig , ui). The second unbranched ray has the median segments enlarged anteriorly, projecting over the anterior ray ( Fig. 42 View Fig , uii); few segments are retrorsely curved ( Fig. 42 View Fig , rc). The third unbranched ray is the longest, forming a short tip ( Fig. 42 View Fig , uiii). The first and second branched anal-fin rays have retrorsely curved distal segments ( Fig. 42 View Fig , rc). The second and third branched rays are shorter, forming a central notch in the distal margin of the anal fin. Posterior branched rays are normally developed, forming a rounded posterior margin, about 20% more elongated than the anterior margin.

The caudal-fin upper lobe is more elongated in mature males. Sexual dimorphism is not investigated as only young females are available.

Distribution. Tatia strigata is recorded from central Amazon basin, Negro river and Casiquiare Channel ( Fig. 6 View Fig ). Tatia strigata is sympatric with T. dunni in the Casiquiare Channel and Negro river.

Remarks. Four branched pectoral-fin rays in T. strigata is not a common count within the genus. Species of Tatia with only four branched pectoral-fin rays are T. boemia , T. gyrina , T. meesi , some T. neivai and some T. intermedia .

A male anal fin with a notched distal margin is observed in both T. strigata and T. aulopygia , but the position of the notch is different. In T. strigata the notch is formed by reduction of the second and third branched rays vs. reduction of fourth and fifth branched rays in T. aulopygia . The notched distal margin in male anal fin is not restricted to Tatia . Such a condition is also observed in Glanidium leopardus , with shortening of the fourth to sixth branched rays.

Material examined. 80 specimens (16.3-55.0 mm SL). Holotype. Brazil: Amazonas : MZUSP 44065 View Materials , male ( 38.9 mm SL), Maués, igarapé Limãozinho ( holotype of Tatia strigata ) . Paratypes. Brazil: Amazonas: MCZ 78092, 1 About MCZ (55.0 mm SL), lake Cristalino, off Negro river near Manaus ; MZUSP 7357 View Materials , 35 View Materials ( 20.5-38.6 mm SL), Maués, igarapé Limãozinho ; MZUSP 7298 View Materials , 23 View Materials ( 16.3-31.2 mm SL) and MZUSP 44066 View Materials , 2 View Materials CS (37.0- 38.9 mm SL), Maués, igarapé of Marau river ; MZUSP 44069 View Materials , 1 View Materials CS female ( 29.4 mm SL), Canumã, igarapé on the left margin of Canumã river . Venezuela : ANSP 165795 About ANSP , 5 About ANSP (24.5-30.0 mm SL), Amazonas: brook of Casiquiare river, downstream from mouth of Pamoni river ( paratypes of Tatia strigata ) .