Tatia luisae, Ribeiro & Silva-Oliveira & Silva & Canto, 2022

Ribeiro, Frank Raynner V., Silva-Oliveira, Cárlison, Silva, Alberto Conceição F. da & Canto, André L. Colares, 2022, New species of driftwood catfish of Tatia (Siluriformes: Auchenipteridae) from rio Tapajós, Brazil, Neotropical Ichthyology (e 210164) 20 (2) : -

Tatia luisae , new species

urn:lsid:zoobank.org:act:09C69D05-7B93-4BC2-9328-8A454590B70A

( Figs. 1–3; Tab. 1)

Holotype. UFOPA-I 1363 , 25.4 mm SL, Brazil, Pará State , Itaituba , Pimental Community, rio Tapajós, 04°33ʼ22.3”S 56°17ʼ56.1”W, 11 Sep 2021, A. Conceição, M. Barbosa, D. Melo & J. Araújo.

Paratypes. Brazil, Pará State , Itaituba : INPA 59670 , 20 , 20.9 –36.0 mm SL, Buburé Community , rio Tapajós , 04°36ʼ57.5”S 56°19ʼ29.9”W, 23 Nov 2021, A. Conceição, M. Lima, D. Melo & J. Araújo. MCP 54773 , 20 , 16.8–30.1 mm SL, Pimental Community , rio Tapajós , 04°33ʼ22.3”S 56°17ʼ56.1”W, 11 Sep 2021, A. Conceição, M. Barbosa, D. Melo & J. Araújo. INPA 59669 , 20 , 18.9–28.3 mm SL, Pimental Community , rio Tapajós , 04°33ʼ22.3”S 56°17ʼ56.1”W, 11 Sep 2021, A. Conceição, M. Barbosa, D. Melo & J. Araújo. UFOPA-I 1358 , 77 , 4 CS, 15.4–24.8 mm SL, Pimental Community, rio Tapajós , 04°33ʼ22.3”S 56°17ʼ56.1”W, 19 Nov 2020, C. Silva-Oliveira & M. Barbosa. UFOPA-I 1359 , 1 , 22.5 mm SL, Penedo Community, rio Tapajós , 05°31ʼ26.7”S 57°06ʼ18.2”W, 10 Sep 2021, A. Conceição, M. Barbosa, D. Melo & J. Araújo. UFOPA-I 1360 , 23.3 mm SL, Buburé Community, rio Tapajós , 04°36ʼ57.5”S 56°19ʼ29.9ʼʼW, 9 Sep 2021, A. Conceição, M. Barbosa, D. Melo & J. Araújo. UFOPA-I 1361 , 48 , 3 CS, 15.7–33.1 mm SL, Pimental Community, rio Tapajós, 04°33ʼ22.3”S 56°17ʼ56.1”W, 11 Sep 2021, A. Conceição, M. Barbosa, D. Melo & J. Araújo. UFOPA-I 1362 , 8 , 22.5–43.3 mm SL, Buburé Community, rio Tapajós, 04°36ʼ57.5”S 56°19ʼ29.9”W, 23 Nov 2021, A. Conceição, M. Lima, D. Melo & J. Araújo .

Diagnosis. Tatia luisae differs from all species of Tatia and Centromochlus , except T. akroa Souza, Sarmento-Soares, Canto & Ribeiro, 2020 and T. britskii Sarmento-Soares & Birindelli, 2015 , by the absence (vs. present) of adipose fin. Tatia luisae differs from T. akroa by the dorsal-fin spine length (16.4–24.3% SL, mean 19.6 vs. 12.3–17.3% SL, mean, 14.7), head depth (56.4–71.9% HL, mean 66.3 vs. 40.6–57.6% HL, mean 47.2), interorbital distance (34.7–45.0% HL, mean 4.0 vs. 46.1–57.9% HL, mean 50.2), and posterior internarial distance (22.1–30.2% HL, mean 25.7 vs. 30.0–38.2% HL, mean 33.3). Tatia luisae differs from T. britskii by the body depth (17.8–24.6% SL, mean 22.6 vs. 14.6–17.1% SL, mean 16.2), dorsal-fin spine length (16.3–24.3% SL, mean 19.7 vs. 13.3–15.6% SL, mean 14.3), head depth (56.4–71.9% HL, mean 66.3 vs. 46.3–52.7% HL, mean 49.5), anterior internarial distance (14.6–24.2% HL, mean 21.9 vs. 29.2– 33.0% HL, mean 31.2), and posterior internarial distance (22.1–30.2% HL, mean 25.7 vs. 31.5–34.7% HL, mean 33.5). Tatia luisae further differs from T. aulopygia (Kner, 1857) , T. altae (Fowler, 1945) , T. brunnea , T. caudosignata DoNascimiento , Albornoz- Garzón & García-Melo, 2019, T. dunni (Fowler, 1945) , T. ferrarisi (Birindelli, Sarmento-Soares & Lima, 2015) , T. galaxias Mees, 1974 , T. gyrina (Eigenmann & Allen, 1942) , T. intermedia , T. jacaratia Pavanelli & Bifi, 2009 , T. meesi Sarmento-Soares & Martins Pinheiro, 2008 , T. meridionalis , T. neivai (Ihering, 1930) , T. perugiae (Steindachner, 1882) , T. punctata Mees, 1974 , T. reticulata Mees, 1974 and T. strigata Soares-Porto, 1995 by dotted color pattern on sides of body (vs. mottled, spotted or reticulated on flanks). Differs from T. aulopygia , T. boemia Koch & Reis, 1996 , T. brunnea , T. caxiuanensis Sarmento-Soares & Martins-Pinheiro, 2008 , T. caudosignata , T. dunni , T. galaxias , T. gyrina , T. intermedia , T. jaracatia , T. meesi , T. neivai , T. nigra , and T. strigata by the absence (vs. presence) of anterior nuchal plate.

Description. Morphometric data in Tab. 1. Small size species, largest specimen examined 43.3 mm SL. Body elongate; depth of trunk proportionally greater than its width. Head slightly depressed anteriorly, progressively more elevated posteriorly. Profile of head longer than broad in dorsal view, slightly convex from snout tip to pectoral-fin insertion. In lateral view, dorsal profile of body from dorsal-fin base to caudal fin slightly to distinctly convex. Ventral profile of head and abdomen approximately straight. Greatest body width at postorbital region. Ventral profile of body gently concave between pelvic-fin base and caudal-fin origin. Greatest body depth at dorsal-fin origin. Trunk from pectoral-fin base to caudal peduncle gradually compressed. Lateral line extending onto caudal-fin base, midlateral, nearly straight, with superficial tubular ossicles directed posteroventrally. Head covered by integument thick, obscuring bones of cranial roof; adipose eyelid weakly developed. Snout short, less than half head length; anterior margin rounded. Eye on anterior half of head; laterally placed and oriented equally visible in dorsal and ventral view. Mouth wide, terminal. Posteriormost mouth corner extending slightly behind vertical through anterior orbital margin. Upper and lower lips thin, weakly developed; upper lip extended posterolaterally, fleshy rictal fold well developed; snout margin approximately rounded in dorsal view; anterior nostril tubular, anteriorly oriented, located on anterior border of snout; posterior nostril somewhat larger, rounded, anteriorly oriented, limited anteriorly by small skin flap; transverse distance between anterior nostrils slightly smaller than distance between posterior ones. Maxillary barbel elongate, reaching approximately vertical through middle of dorsal fin or slightly beyond; adpressed maxillary barbel fits in groove ventrally to orbit, from dorsal portion of rictal fold extending ventrolaterally to operculum; mental barbels short, tips not reaching pectoral-fin base; mental barbels inserted anterior to vertical through posterior margin of eyes. Inner mental barbel about two-thirds length of outer mental. Posterior process of cleithrum moderately long, reaching or extending slightly beyond vertical through origin of dorsal-fin spine. Coracoid process small, shorter than pectoral fin base.

Dorsal fin II,5; originated slightly posterior to vertical through terminus of pectoral-fin base; spinelet triangular anteriorly, covered by thin layer of skin; dorsal-fin spine straight, strong, pungent, shorter than first branched ray, with filamentous tip; anterior margin of dorsal-fin spine with 13–16 denticulations, posterior margin with 2–5 serrations on distal portion (n = 20); first branched ray longest, subsequent rays decreasing gradually in length; last dorsal-fin ray approximately half length of first branched ray; distal margin of dorsal fin rounded.

Adipose fin absent. Pectoral fin I,5; pectoral spine, rigid, pungent; its anterior margin with 17–21 serrations; posterior margin with 10–16 serrations (n = 20); pectoral-fin spine denticulations becoming progressively more prominent distally. First branched ray longest, subsequent rays decreasing in length; posterior margin of pectoral fin obliquely truncate. Pelvic fin i,5; its origin at or slightly posterior to middle of body; second branched ray longest, subsequent rays decreasing in length; posterior pelvic-fin margin rounded. Anal fin iii–iv,6; its origin approximately on last third of standard length, posterior to vertical through tip of pelvic-fin rays; last ray unbranched and first branched rays longest; distal margin rounded. Caudal fin i,15,i; deeply forked; dorsal and ventral caudal-fin lobes equal in length; outer principal rays unbranched, seven branched rays on dorsal lobe and eight branched rays on ventral lobe; 12–14 upper procurrent, 12–14 lower procurrent rays (n = 4).

Anterior nuchal plate absent; anterior margin of middle nuchal plate sutured to parieto-supraoccipital. Middle nuchal plate wide, with deeply concave lateral margins; posterior nuchal plate short, projected laterally, with prominent tip ( Fig. 2). Mesethmoid longer than broad, lateral margin concave; mesethmoid cornua slender distally. Nasal ossified as tubular bone situated between mesethmoid cornua and lateral ethmoid, free from mesethmoid. Lateral ethmoid not participating in dorsal face of cephalic shield. Anterior cranial fontanel narrow and elongate, located from mesethmoid to midpoint of medial margins of frontals; posterior fontanel absent. Maxilla slightly elongated. Jaws of equal sizes; premaxilla and dentary slender, each with four or five rows of robust conical teeth.

Hyomandibula broad, sutured to both quadrate and metapterygoid. Metapterygoid as wide lamina, joined to quadrate via suture ( Fig. 3). Quadrate trapezoidal, with broad base, sutured to preopercle, hyomandibula and metapterygoid; long preopercle ventral margins sutured to both quadrate and hyomandibula; suprapreopercle present as long canal bone; preopercular canal exiting on anterior portion of pterotic. Opercle laminate, ornamented with shallow ridges, and broadly subtriangular ( Fig. 3).

Infraorbital 1 with ventro-lateral process restricted to anterior border of eye, followed by canal-like bones, in incomplete infraorbital series. Lateral line approximately straight, inconspicuous, with ossified canal bones only anteriorly, unbranched and ending at caudal-fin base. Branchiostegal membrane broadly united to isthmus. Total vertebrae 33–34; ribs 7–10, becoming progressively smaller in size posteriorly.

Color in alcohol. Background color light brown to light cream, dorsally darker. Mid-dorsal and dorsolateral portions of body densely covered with dark chromatophores. Dorsolateral dots formed by both dermal and epidermal pigments. Dark coloration on body extending ventrally over lateral area above lateral midline, becoming sparse ventrally. Dark pigmentation on caudal peduncle extending along entire lateral area. Dorsal surface of head with dark pigmentation, except for broad unpigmented areas in postorbital region, over cranial fontanel, and at anterior margin of snout; cranial shield surface densely covered with dark chromatophores extending laterally to eyes and opercle. Lateral surface of head with scattered pigmentation on opercle and sometimes branchiostegal membrane. Maxillary barbel white to light yellow with scattered chromatophores on basal portion. Mental barbels white to light yellow, lacking dark pigmentation. Dorsal fin with dark spot in proximal region; remainder of fin unpigmented. Caudal-fin base with scattered dark chromatophores, becoming completely hyaline distally. Pectoral, pelvic, and anal fins completely hyaline ( Fig. 1).

Color in life. Ground color light gray to light cream, with dark chromatophores on head and dorsolateral region, more concentrated on mid-dorsal portion. Dorsolateral dots formed by both dermal and epidermal pigments. Dark coloration on body extending ventrally over lateral area above lateral line, becoming sparse ventrally on anterior and posterior positions of trunk; dark pigmentation on caudal peduncle extending along all lateral area. Dorsal surface of head densely pigmented, except postorbital region, over cranial fontanel, and at anterior margin of snout; dark chromatophores extending laterally to eyes and opercle. Lateral surface of head with scattered pigmentation on opercle and infraorbital portion. Maxillary barbel white with scattered chromatophores on basal portion. Mental barbels white, lacking dark pigmentation. Dorsal fin with dark spot in proximal region; remainder of fin unpigmented. Caudal-fin base with scattered dark chromatophores; completely hyaline distally. Pectoral, pelvic, and anal fins similar to preserved specimens ( Fig. 4).

Sexual dimorphism. In one nuptial and five males with partially modified anal fin for insemination ( Fig. 5). Proximal radials connected to each other in modified anal fin of adult males. All proximal radials closely together, not fused, sutures visible. Least unbranched and first branched anal-fin rays closely together to form a structure of support for the intromittent organ. Urogenital opening at base of anal fin as simple pore at the distal tip of a tubular structure bound by integument. Deferent duct externally visible as a genital papilla. Female and immature males have anal-fin proximal radials and rays separate and anal fin obliquely oriented, with distal tip rounded ( Fig. 4). Female with slit-like urogenital opening.

Geographical distribution. Tatia luisae is currently known only from the middle rio

Tapajós, upstream of the rapids of São Luiz do Tapajós, at Itaituba Municipality ( Fig. 6).

Etymology. The specific epithet luisae is in honor to the Brazilian ichthyologist Luisa M. Sarmento-Soares, in recognition of her many contributions to the systematics of Neotropical catfishes of the subfamily Centromochlinae . A noun in the singular genitive case.

Ecological notes. Similar to many auchenipterids, Tatia luisae appears to be an active night feeder. Tatia luisae specimens were observed and collected during the night while they were swimming just below the water surface. Six dissected specimens ( UFOPA-I 1358 and 1361) were found to have fed on insects, especially those that fall onto the water surface such as Ephemeroptera. The stretch where the specimens were collected is characterized by moderate to fast-flowing clear waters, substrate composed predominantly of sand and rocks, neutral waters (pH 7.2), water oxygenation>70%, and water surface temperature at around 32ºC. This stretch of the rio Tapajós has suffered substantial anthropogenic pressure in recent years, e.g., it has received a large volume of tailings from mining activities, mainly from the Crepori and Jamanxim rivers, which has drastically altered some of its water characteristics, especially its transparency.

Conservation status. Tatia luisae is known only from three localities corresponding to an Extent of Occurrence ( EOO) of approximately 2,500 km 2. However, individuals of T. luisae were abundant near the Pimental rapids and Buburé Community. Additionally, continuing population decline was not observed, as well as area of occupancy, quality of habitat, and number of locations or subpopulations. Therefore, T. luisae can be classified as Least Concern ( LC) according to the International Union for Conservation of Nature ( IUCN) c ategories and criteria ( IUCN Standards and Petitions Committee, 2022).