Cambeva tourensis Costa, Feltrin & Katz, 2023

Costa, Wilson J. E. M., Feltrin, Caio R. M., Mattos, José Leonardo O., Amorim, Pedro F. & Katz, Axel M., 2023, Phylogenetic relationships of new taxa support repeated pelvic fin loss in mountain catfishes from southern Brazil (Siluriformes: Trichomycteridae), Zoologischer Anzeiger 305, pp. 82-90 : 86-88

publication ID	https://doi.org/ 10.1016/j.jcz.2023.06.003
persistent identifier	https://treatment.plazi.org/id/624D3E09-FF93-FF98-FCCF-FD0D8AC641B8
treatment provided by	Felipe
scientific name	Cambeva tourensis Costa, Feltrin & Katz
status	sp. nov.

Treatment

3.3. Cambeva tourensis Costa, Feltrin & Katz sp. nov

( Fig. 3B View Fig , Fig. 4D–F View Fig , Fig. 7 View Fig ).

Urn:lsid:zoobank.org:act:lsid:zoobank.org:act: 8A8A5D17-8898- 48D1-B650-D25D80F05430.

Cambeva flavopicta non Cambeva flavopicta Costa et al., 2020c : Ferrer, 2021: 230 (misidentification).

Rio Uruguai basin, 28 ◦ 40′35″S 50 ◦ 12′06″W, about 1050 m asl; C. R. M. Feltrin, 16 July 2022 .

3.3.1.2. Paratypes. UFRJ 13362, 2 ex., 44.3 and 58.5 mm SL; UFRJ 13363, 3 ex., 37.4–57.5 mm SL (C&S); CICCAA 07735, 2 ex., 37.5–39.3 mm SL; UFRJ 13283, 1 ex., 36.1 mm SL (DNA); collected with holotype .

3.3.2. Diagnosis

Cambeva tourensis differs from all congeners, except C. flavopicta , C. pascuali , C. podostemophila , and C. tropeira , by the absence of pelvic fins and girdle (vs. pelvic fins and girdle present and well-developed). Cambeva tourensis is distinguished from C. podostemophila by having fewer branchiostegal rays (eight or nine vs. ten) and more vertebrae (39 vs. 37); from C. pascuali and C. tropeira by having six pectoral-fin rays (vs. five in C. pascuali and eight in C. tropeira ); from C. flavopicta and C. pascuali by the absence of a filament on the extremity of the first pectoral-fin ray; from C. flavopicta and C. tropeira by the absence of anterior segment of the infraorbital latero-sensory canal (vs. presence); from C. flavopicta by having fewer dorsal (18 vs. 20–23) and ventral (13 vs. 16–18) procurrent caudal-fin rays, fewer opercular odontodes (9–11 vs. 15–16), and jaw teeth sub-incisiform, tip rounded (vs. conical, tip sharply pointed). Cambeva tourensis also differs from its sister taxa, C. flavopicta , by the following osteological features: autopalatine with a well-developed postero-lateral process ( Fig. 4D View Fig ; vs. rudimentary, almost indistinct, Costa et al., 2020b: Fig. 2A View Fig ); sesamoid supraorbital slender, without lateral projections, and long, about three times antorbital length ( Fig. 4D View Fig ; vs. broad, with lateral expansion, and short, about one and half times or twice lacrimal-antorbital length, Costa et al., 2020b: Fig. 2A View Fig ); a more slender opercular odontode patch, its depth about half length of dorsal hyomandibula articular facet ( Fig. 4E View Fig ; vs. depth of the opercular odontode patch slightly smaller than the length of the dorsal hyomandibula articular facet, Costa et al., 2020b: Fig. 2B View Fig ); lateral process of the parurohyal broad ( Fig. 4F View Fig ; vs. relatively narrow, Costa et al., 2020b:

Fig. 2C View Fig ); and more pleural ribs (17 or 18 vs. 13 or 14).

3.3.1. Material examined

3.3.1.1. Holotype. UFRJ 13361, 63.9 mm SL; Brazil: Rio Grande do Sul State: Bom Jesus Municipality: Rio dos Touros, tributary of Rio Pelotas ,

3.3.3. Description

3.3.3.1. General morphology. Morphometric data appear in Table 2. Body relatively slender, subcylindrical in anterior region, compressed in posterior region. Greatest body depth in area midway distance between posterior limit of head and anal-fin origin. Dorsal and ventral profile of trunk gently convex between head and dorsal-fin origin, about straight along caudal peduncle. Dorsal profile of head nearly straight, ventral profile slightly convex. Anus and urogenital papilla at vertical immediately posterior to dorsal-fin origin. Head sub-trapezoidal in dorsal view. Anterior profile of snout slightly convex in dorsal view. Eye small, dorsally positioned on head, in its anterior half. Anterior nostril slightly nearer posterior nostril than orbit. Barbels moderate in length; nasal barbel reaching area between orbit and opercle; maxillary barbel reaching between middle and posterior portions of interopercular patch of odontodes; rictal barbel reaching anterior portion of interopercular patch of odontodes. Minute skin papillae on head surface. Mouth subterminal. Jaw teeth sub-incisiform, tip rounded, arranged in three irregular series. Total premaxillary teeth 44 or 45, total dentary teeth 45–47.

Dorsal and anal fins subtriangular, margins rounded. Total dorsal-fin rays 11 or 12 (ii–ii + II +7), total anal-fin rays 9 or 10 (ii +II +5–6). Anal-fin origin at vertical through anterior half of dorsal-fin base. Dorsal-fin origin at vertical through centrum of 22nd or 23rd vertebra; anal-fin origin at vertical through centrum of 25th or 26th vertebra. Pectoral fin subtriangular in dorsal view, posterior margin convex, first pectoral-fin ray slightly longer than second ray, not forming terminal filament. Total pectoral-fin rays 6 (I + 5). Pelvic fin and pelvic girdle absent. Caudal fin subtruncate, posterior corners rounded. Total principal caudal-fin rays 13 (I +11 +I), total dorsal procurrent rays 18 (xvii + I), total ventral procurrent rays 13 (xii +I).

3.3.3.2. Laterosensory system ( Fig. 3B View Fig ). Supraorbital sensory canal continuous, posteriorly connected to posterior section of infraorbital canal, with three pores: s1, adjacent to medial margin of anterior nostril; s3, adjacent and just posterior to medial margin of posterior nostril; s6, in transverse line through posterior half of orbit. Pore s6 slightly nearer orbit than its paired homologous pore. Anterior infraorbital sensory canal absent. Posterior infraorbital sensory canal with two pores: pore i10, adjacent to ventral margin of orbit, and pore i11, posterior to orbit. Postorbital canal with two pores: po1, at vertical through posterior portion of interopercular patch of odontodes, and po2, at vertical through posterior portion of opercular patch of odontodes. Lateral line with two pores situated above and slightly posterior to pectoral-fin base.

3.3.3.3. Osteology ( Fig. 4D–F View Fig ). Mesethmoid robust, slightly broadened between cornu and lateral ethmoid, anterior margin about straight, mesethmoid cornu extremity blunt. Lateral ethmoid without lateral projections. Antorbital thin, elliptical, sesamoid supraorbital narrow and long, about three times antorbital length. Premaxilla long, sub-rectangular. Maxilla shorter than premaxilla, slender, without posterior process, slightly curved. Autopalatine sub-rectangular in dorsal view, medial margin nearly straight, lateral margin slightly concave; postero-lateral process well-developed, about three fourth of autopalatine length excluding anterior cartilage. Metapterygoid moderate in size, sub-trapezoidal, longer than deep. Quadrate with anterior constriction at dorsal process base. Hyomandibula long, anterior outgrowth horizontal length about 1.5 times horizontal metapterygoid length; middle portion of dorsal margin of hyomandibula outgrowth with pronounced concavity. Opercle elongate, longer than interopercle. Opercular odontode patch depth about half length of dorsal hyomandibula articular facet. Opercular odontodes 9–11; odontodes pointed, about straight, transversely arranged. Dorsal process of opercle short, blunt. Opercular articular facet for hyomandibula with prominent rounded flap, articular facet for preopercle minute. Interopercle short, interopercular odontode patch length about one two times and half opercular odontode patch depth. Interopercular odontodes 25–27; odontodes pointed, arranged in irregular longitudinal rows. Preopercle slender, with minute ventral projection. Parurohyal robust, lateral process broad, triangular, slightly curved posteriorly; parurohyal head with prominent anterolateral paired process; middle foramen small, elliptical; posterior process short, about half of distance between anterior margin of parurohyal and anterior insertion of posterior process. Branchiostegal rays 8 or 9. Vertebrae 39. Ribs 17 or 18. Two dorsal hypural plate corresponding to hypurals 3 + 4 and 5; single ventral hypural plate corresponding to hypurals 1 +2 +parhypural.

3.3.3.4. Colouration in alcohol. Flank, dorsum and head side pale yellow with irregularly arranged dark brown blotches, often coalesced to form reticulate pattern. Venter and ventral surface of head yellowish white. Fins hyaline with dark brown dots on basal region. Barbels brown.

3.3.4. Distribution and habitat

All specimens of the type series of C. tourensis were collected in the Rio dos Touros, upper Rio Uruguai basin, about 1045 m asl ( Fig. 5 View Fig ). At the type-locality, Rio dos Touros is about 70 m wide and about 1.5 m deep in deepest areas. Specimens were found burrowed in amphibian plants rooted among small and medium pebbles (about 1–20 cm), in stretches of moderate to fast current, at low depths, about 40 cm or slightly less. Remnants of Chironomidae ( Diptera ) and Odonata larvae were found in the gut content of the three cleared and stained paratypes.

3.3.5. Etymology

The name tourensis is an allusion to the Rio dos Touros, the only locality where the new species was found.