Tatia intermedia (Steindachner, 1877)

Sarmento-Soares, Luisa Maria & Martins-Pinheiro, Ronaldo Fernando, 2008, A systematic revision of Tatia (Siluriformes: Auchenipteridae: Centromochlinae), Neotropical Ichthyology 6 (3), pp. 495-542 : 523-526

Tatia intermedia (Steindachner, 1877)

Figs. 27-29

Centromochlus aulopygius . Günther, 1864 [ Essequibo]. Eigenmann & Eigenmann, 1891: 34 [in part, Essequibo]. Eigenmann, 1910: 395 [ Essequibo]. Eigenmann, 1912: 197, pl. 20 fig. 1 [stream below Potaro Landing, Wismar; Guyana]. Puyo, 1949: 97 [streams on region ofApprouage]. Miranda Ribeiro, 1962: 9 [Araguaia river, Aruanã, Goiás].

Centromochlus intermedius Steindachner, 1877: 664 , footnote [type locality: Marabitanos, Pará]. Fisher, 1917: 422 [in part, Tapajós river at Santarém ].

Centromochlus perugiae . Vaillant, 1899: 155 [Lunier or Carnot river, tributary of the Carsevenne, now Calçoene, Amapá]; Vaillant, 1900: 124, 127 [Carnot river].

Tatia intermedia . Miranda Ribeiro, 1911: 360 [generic designation, assignment to Tatia , in part, Marabitanos]. Mees, 1974: 59-63 [notes and distribution, in part, Pará]. Sands, 1984: 37 [listing]. Kobayagawa, M. 1991:104 [reference]. Soares-Porto 1995:204 [citation]. Soares-Porto, 1998: 349 [citation]. Ferraris, 2003:477 [checklist]. Ferraris, 2007: 77 [checklist].

Tatia aulopygia . Gosline, 1945: 10 [in part, Essequibo]. Fowler, 1951: 470 [ Guyana]. Lowe Mc Connell, 1964: 116, 141 [Simoni stream, Rupununi, Guyana]. Mees, 1974: 59-63, fig. 11. [in part, Suia Missu, Mato Grosso]. Sands, 1984: 38-39 [Xingu river]. Burgess, 1989: 242 [northeastern South America]. Soares-Porto, 1995:205 [citation], Soares-Porto, 1998:333 [citation].

Centromochlus . Lowe-McConnell, 1987: 282, fig. 12.2 d.

Diagnosis. Tatia intermedia is distinguished by the following combination of characteristics: wide elliptical cranial fontanel; short postcleithral process not reaching vertical through origin of dorsal fin; body coloration variable, usually with elliptical spots along sides of body, large specimens with faint spots; or color pattern uniformly pale brown; caudal fin with small spots or pale brown. The only other Tatia with a variable coloration is T. galaxias . Tatia intermedia differs from T. galaxias by its short postcleithral process (vs. long in T. galaxias ); its small eye, 21.4-26.3% HL (vs. 37.0-42.9% in T. galaxias ) and its long snout 38.8-44.3% HL (vs. 23.1-28.9% in T. galaxias ). Additional features useful for distinguishing T. intermedia include: nasal ossified with wide medial flanges partially sutured to lateral margin of mesethmoid; caudal-fin lobes of mature females with same length, but mature males with elongated upper lobe.

Description. Measured specimens 50.4-91.2 mm SL; morphometric data presented in Table 9. Body slim, head slightly depressed dorso-ventrally. Head large, robust, outline of head in dorsal view somewhat elliptial, broader than long. Trunk from dorsal-fin base to caudal peduncle becoming gradually compressed laterally. Lateral profile of head from snout tip to above 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 posterolaterally 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 proportionally the same as distance between posterior ones. Maxillary barbel short, almost reaching vertical through origin of dorsal fin; mental barbel short, tips not reaching pectoral-fin base, arranged in arc along ventral surface of jaw; inner mental barbel about 55.0-65.0% length of outer mentals. Postcleithral process short, not reaching vertical through origin of dorsal fin. Caudal peduncle deep, depth about 13.9-18.1% SL.

Rostral border of cranium broad with large mesethmoid; premaxilla underneath with synchondral articulation; cranial fontanel large, elliptical, bounded by mesethmoid and frontal ( Fig. 28 ); nasal ossified, with medial flanges sutured to lateral margin of mesethmoid; autopalatine tubular, oriented obliquely to longitudinal axis of body; maxilla small, shorter than autopalatine. Prevomer expanded anteriorly with well developed arrow-shaped lateral processes, bearing small teeth attached to process in examined large specimens (> 74 mm SL). Jaws of equal size; premaxilla and dentary with three to four 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, opercular bones and branchial skeleton as in generic description. Suprapreopercle present as short robust canal bone. Six branchiostegal rays articulated with hyoid arch: four with anterior ceratohyal and two with posterior ceratohyal; last one largest and laminar expanded.

Five infraorbital bones in incomplete series. Infraorbital 1 thin, with short ventro-lateral process on anterior border of eye; remaining infraorbitals thin, reduced to canalicular portions. Infraorbital 2 smallest, close to infraorbital 1, followed by non-ossified portion of canal below eye and three posterior ossicles bordering eye posteriorly: last one in contact to sphenotic. Lateral line on body with ossified canal bones posteriorly to vertical through pelvic fin origin.

Dorsal fin I,4-5 (n=12); dorsal-fin spine with 12-17 antrorse serrations along entire anterior margin, posterior margin smooth. Pectoral fin I,5 (n=12), pectoral-fin spine with 14-17 antrorse serrations along anterior margin; 11-16 retrorse serrations along posterior margin; serrations along both margins become progressively larger towards spine tip. Pelvicfin i,5 (n=12); margin rounded. Adipose fin small, origin on vertical through end of anal-fin base. Anal fin iii, 6-7 (n=12); 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, 10-16 upper procurrent, 15-22 lower procurrent rays (n=12). Pleural ribs 10 attached to consecutive vertebrae. Post-Weberian vertebrae 35-36 (n=5).

Color in alcohol. In the original description of Centromochlus intermedius, Steindachner (1877) did not mention the color pattern of the two syntypes. Steindachner (1881) noted a copper-colored body with regular spots and a silver gray caudal fin in specimens from Jutaí and Jutuarana, Amazon basin, when comparing those specimens with the syntypes. Only one decolorized syntype of C. intermedius (NMW 47355) was available for our examination. As the original color pattern for the syntypes was not clearly stated in species description, specimens from Marabitanos, the type locality, possibly were uniformly light brown. This is in agreement with the color pattern found in specimens from the Capim river, eastern Pará ( Fig. 27a ). Specimens from eastern Pará have the dorsal surface of the head and dorsal mid-line brown, the sides usually dark brown, the ventral contour of the head around the chin, lips and anterior nostrils brown, the body whitish ventrally, the dorsal fin with a dark base and irregular spots towards the fin tip, the pectoral, pelvic and adipose fins hyaline, and the caudal fin pale brown.

Color variation. Geographical and individual variation in coloration was observed throughout the distribution of T. intermedia . Besides the coloration in eastern Pará specimens ( Fig. 27a ), other patterns are found. In specimens fromAmapá, Suriname and Guyana the common pattern is the presence of large light ellipsoid spots on dorsum and sides of body to caudal-fin tips; pale nuchal shield; and pectoral fin usually with transverse dark bands ( Fig. 27b ).

In the lower Amazon and upper Tocantins some specimens have a light brown body coloration and spotted caudal fin. In the upper Tocantins river drainage specimens usually have small light spots over the body becoming smaller towards the caudal-fin tip, a dark nuchal shield, and the pectoral fin usually light brown ( Fig. 27c ). Sometimes specimens with a spotted body and caudal fin co-occur with specimens having a uniformly light brown body and spotted caudal fin. In some localities specimens with light brown bodies may have the caudal fin spotted or plain light brown.

Differences in overall intensity of pigmentation were observed relative to size. In some very young specimens, less than 20 mm SL, the spots are vivid and sharply defined compared to some large specimens (up to 70 mm SL), wherein the spots are pale and poorly defined. The thick superficial skin layer obscures the coloration pattern in large T. intermedia , as is seen among other large sized Tatia .

Sexual dimorphism. Based on examination of gonads, T. intermedia attains sexual maturity above 50.4 mm SL. In mature females a genital papilla is not evident. A thick genital papilla is visible in mature males, with a short deferent duct. The anal fin of mature male ( Fig. 29 ) is strongly modified, with the anterior rays enlarged and thickened. The first unbranched ray have segments fused, immediately preceded by a large tegumentary keel ( Fig. 29 , tk). The second unbranched ray is elongated coalescing with the subsequent, third, ray. The third unbranched plus first branched are the longest rays, forming a pointed tip. The distal segments are antrorsely curved ( Fig. 29 , ac) on third unbranched ray. First and second branched rays with small retrorsely curved distal segments along outer margin ( Fig. 29 , rc). Posterior branched rays are progressively shorter, with the last ray not reduced ( Fig. 29 , b 6 ).

Hemal spines 16-19 interdigitating with the anal-fin pterygiophores; being the hemal spines 17-19 thickened in mature males, but undifferentiated in females. Caudal-fin lobes with the same length in mature females; in mature males the upper lobe is more elongated.

Distribution. Originally described from the Amazon basin, T. intermedia is the most widely distributed member of the genus. It occurs in the upper reaches of the Araguaia, Tocantins, Xingu, and Capim rivers, tributaries of the lower Amazon of Brazil, northwards to the Suriname coastal rivers and the Essequibo river in Guyana ( Fig. 6 ).

Remarks. Recognition of T. intermedia remained difficult for a long time. Mees (1974: Fig. 11 ) mistakenly associated the specimens from Suia Missu river in Mato Grosso, Brazil, as T. aulopygia . Mees’ specimens were young, bearing small spots over the body, and their coloration conforms with that observed for other T. intermedia . Tatia intermedia and T. aulopygia are compared under the redescription of T. aulopygia .

The pectoral-fin spine with transverse bands was considered distinctive for T. intermedia by Soares-Porto (1998). Herein this feature is considered variable, as in some populations the spine is barred, some not. Soares-Porto (1998: 341) considered a barred spine as a derived feature shared between T. intermedia and T. brunnea , but such a condition varies intraspecifically in both species.

Some large T. intermedia may be superficially similar to large T. dunni , as both species may have faint light spots on the sides of the body. In spite of this similarity, T. intermedia differs by having a short postcleithral process, not reaching the vertical through the dorsal-fin origin (vs. long, reaching vertical through dorsal-fin origin in T. dunni ); a toothed prevomer in large specimens (vs. edentulous in large T. dunni ); and a male modified anal fin with 3-5 elongate antrorse curved segments (vs. 1-3 short antrorse curved segments in T. dunni ).

Material examined. 57 specimens (13.1-91.2 mm SL). Syntype. NMW 47355, 1 ( R), Brazil: Pará: Marabitanos (syntype of Centromochlus intermedius ). Brazil: Amapá : MNRJ 12132 , 1 (66.0 mm SL), Brazil: Amapá : Maruanum river, tributary of Matapi river, Macapá . MNRJ 12133 , 1 (31.9 mm SL) and MNRJ 12134 , 9 (40.2- 65.1 mm SL), Brazil: Amapá : Aporema river in Fazenda Modelo do Aporema, tributary of Araguari river . Brazil: Goiás : MNRJ 5896 , 2 (28.0- 66.6 mm SL), Brazil: Goiás : Araguaia river , Aruanã (older Leopoldina). Brazil: Mato Grosso : MZUSP 44256 , 2 (29.5-35.2 mm SL), Brazil: Mato Grosso : lake Ipavu, Parque Nacional do Xingu . RMNH 26491 , 2 (20.3-31.6 mm SL), Brazil: Mato Grosso : Suia Missu river (=suiá miçú). Brazil: Pará : INPA 2978 , 1 (45.4 mm SL), igarapé Tucuruizinho , Tocantins river. INPA 11076 , 1 (84.7 mm SL), Tocantins river. INPA 21006 , 2 (50.4-56.5 mm SL), Trombetas river . MZUSP 9332 , 1 (37.3 mm SL), igarapé Ribeira, near Badajós . MZUSP 43250 , 15 (19.0-40.0 mm SL), lake Bernardino, near Badajós, Capim river ; Km 97 . MZUSP 44125 , 2 (24.1 mm SL) ; MZUSP 44255 , 5 (29.6-65.3 mm SL), Vila Santana, Capim river . MZUSP 44257 , 7 (33.0- 48.4 mm SL) and MZUSP 47503 , 1 , CS, igarapé Caranandena, Capim river . MZUSP 47507 , 20 (17.2-49.0 mm SL), lake Maria Preta, Capim river ; MZUSP 47508 , 1 (40.0 mm SL), igarapé Jari-Mirim, Capim river ; MZUSP 50860 , 1 (17.2 mm SL), igarapé Canteiro, near Vila Santana, Capim river . MZUSP 44254 , 3 (13.1-16.4 mm SL), igarapé Oxipucu, Mocajuba , Tocantins river. MCZ 46032, 1 (20.8 mm SL), Arari river . MZUSP 50861 , 1 (24.2 mm SL), Arari river, Arari waterfalls, Marajó island . MCZ 46130, 3 (37.3-40.6 mm SL) ; MZUSP 43139 , 5 (35.2-42.0 mm SL) ; MZUSP 47504 , 1 CS, and RMNH 26492 , 1 (40.0 mm SL) igarapé Paracuri, near Icoaraci, Belém. Tocantins : INPA 20042 , 1 (58.2 mm SL) Araguari river, locality of Ariranhas in Caseara district . MZUSP 41838 , 1 (55.5 mm SL), córrego Jóia, Santa Rita do Araguaia . MZUSP 41422 , 1 (57.7 mm SL), Córrego Jacaré, Santa Rita do Araguaia. Suriname . RMNH 26195 , 2 (51.3- 55.1 mm SL) ; RMNH 26199 , 12 (38.5-50.0 mm SL), Sipaliwini . RMNH 26201 , 1 (27.4 mm SL), stream near aerodrome Käysergebergte . ZMA 105.791 , 3 (51.2-74.2 mm SL) ( R), stream on left margin of Suriname river, 2,5 km north from Botopasi Village , Brokopondo district . Guyana. AMNH 12947 , 1 (72 mm SL), Wismar . AMNH 17643 , 1 (91.2 mm SL), Cuyuni river . CAS 24798, 1 (49.3 mm SL) Wismar river , Demerara, Demerara basin .

Figures

Fig. 27. Tatia intermedia.(a) MZUSP44255, male, 65.5 mm SL, Capim river, Pará State, Brazil.(b) ZMA 105.523, male, 39.0 mm SL, Gran Mau stream, Suriname. (c) INPA 11076, female, 84.7 mm SL, Tocantins river, Pará State, Brazil.

Fig. 28. Neurocranium of Tatia intermedia, MZUSP 44255, 65.5 mm SL. Dorsal view.Abbreviations: ep, epioccipital; fo, single cranial fontanel, fr, frontal; le, lateral ethmoid; me, mesethmoid; na, nasal; n1, first nuchal plate, n2; second nuchal plate; n3, third nuchal plate; pe, posterior epioccipital process; ps, posttemporal-supracleithrum; pt, pterotic; so, supraoccipital; sp, sphenotic. Scale bar = 1 mm.

Fig. 29. Male modified anal fin of Tatia intermedia, MZUSP 44255, 65.5 mm SL. Left side lateral view.Abbreviations: ac, antrorsely curved denticulation; b1, branched first ray; b6, branched sixth ray; dd, deferent duct; rc, retrorsely curved denticulation; tk, tegumentary keel; ui, unbranched first ray; uii, unbranched second ray; uiii, unbranched third ray. Scale bar = 1.0 mm.

Fig. 6. Drainage map of northern South America illustrating the geographic distribution of the species of Tatia. Symbols may represent more than one locality. Base map by Marilyn Weitzman.

Fig. 11. Neurocranium of Tatia boemia, MCP 12949, paratype, 59.9 mm SL. Dorsal view.Abbreviations: ep, epioccipital; fo, single cranial fontanel; fr, frontal; le, lateral ethmoid; me, mesethmoid; na, nasal; n2; second nuchal plate; n3, third nuchal plate; ps, posttemporal-supracleithrum; pt, pterotic; so, supraoccipital; sp, sphenotic. Scale bar = 1.0 mm.