Cambeva rotundipinna Costa, Feltrin & Katz, 2024

Costa, Wilson J. E. M., Feltrin, Caio R. M., Mattos, José Leonardo O. & Katz, Axel M., 2024, Top mountain areas of subtropical southern Brazil sheltering four new small-ranged catfishes (Siluriformes, Trichomycteridae): relationships and taxonomy, Evolutionary Systematics 8 (2), pp. 199-218 : 199-218

Cambeva rotundipinna Costa, Feltrin & Katz sp. nov.

Figs 4 J – L , 10 , 11 , Table 6

Type material.

Holotype. Brazil • 78.0 mm SL; Brazil: Santa Catarina State: Matos Costa Municipality: Paca road: Rio da Paca, tributary of Rio Jangada, Rio Iguaçu drainage, Rio Paraná basin ; 26 ° 25 ' 02 " S, 51 ° 15 ' 42 " W; about 1000 m asl; 1 Apr. 2023; C. R. M. Feltrin and L. Sebben, leg.; UFRJ 14070 .

Paratypes. All from Santa Catarina State: Matos Costa Municipality: Paca road: Rio da Paca, tributary of Rio Jangada, Rio Iguaçu drainage, Rio Paraná basin . Brazil • 2 ex., 44.4–76.3 mm SL; same data as holotype; UFRJ 13820 . • 3 ex. (C & S), 30.3–55.2 mm SL; collected with holotype; UFRJ 14071 . • 1 ex., 30.8 mm SL; collected with holotype; UFRJ 13559 . • 1 ex. (DNA), 27.8 mm SL; 26 ° 25 ' 06 " S, 51 ° 16 ' 30 " W; about 1000 m asl; 30 Jun. 2023; C. R. M. Feltrin, leg.; UFRJ 13560 .

Diagnosis.

Cambeva rotundipinna differs from all other congeners of the Cambeva beta-clade, except C. luteoreticulata , by having a relatively short and rounded caudal fin in specimens above about 60 mm SL (Fig. 10 A ; vs. subtruncate, truncate, emarginate or forked). Cambeva rotundipinna differs from C. luteoreticulata by having fewer procurrent caudal-fin rays (15–17 dorsal and 10 or 11 ventral, vs. 21 or 22 and 15 or 16, respectively), jaw teeth irregularly arranged (vs. arranged in three rows), more opercular odontodes (14–17 vs. nine or ten), longer nasal barbel in specimens above 60 mm SL, reaching area between orbit and opercular patch of odontodes (vs. reaching area anterior to orbit), and a colour pattern of juveniles, in which the flank is light brownish yellow with small black dots irregularly arranged (vs. pale yellow with large, irregularly shaped dark brown to black blotches, more concentrated on its dorsal portion). Cambeva rotundipinna also differs from C. atrobrunnea , another species from western RISE, by having more odontodes (14–17 opercular and 30–34 interopercular, vs. 12 and 20–22, respectively) and a different juvenile colour pattern, comprising black dots irregularly arranged on the flank (Fig. 11 A ; vs. black dots arranged in irregular longitudinal rows, coalesced to form stripe on the anterior flank midline, Fig. 7 A ). Cambeva rotundipinna also differs from both C. atrobrunnea and C. luteoreticulata by having a broader autopalatine, with its largest width about equal to its length (Fig. 4 J , vs. narrower, Fig. 4 D, G ) and a shorter posterior process of the parurohyal, its length about one third of the distance between the anterior margin of the parurohyal and the anterior insertion of the posterior process (Fig. 4 L , vs. longer, Fig. 4 F, I ). Cambeva rotundipinna is also distinguished from all other species of Cambeva endemic to the Rio Iguaçu drainage by the following combination of character states: seven pectoral-fin rays (vs. eight in C. castroi , C. melanoptera , C. crassicaudata , C. stawiarski ; and six in C. galactica , C. naipi , and C. taroba ); absence of the anterior infraorbital (vs. presence in C. galactica , C. naipi , C. papillifera , C. plumbea , and C. taroba ); posterior margin of the caudal fin convex (vs. about straight in C. crassicaudata , C. davisi , C. galactica , C. melanoptera , C. papillifera , C. piraquara , C. plumbea , C. igobi ; straight to slightly concave in C. stawiarski ; bilobed in C. crassicaudata ; and emarginate in C. cauim ); absence of hypertrophied papillae on the ventral surface of the head (vs. presence in C. papillifera ); absence of pectoral-fin filament (vs. presence a well-developed filament in C. taroba and a rudimentary filament in C. davisi and C. piraquara ); nine or 10 opercular odontodes (vs. broad, with 17 or 18 in C. mboycy ; 15 or 16 in C. davisi ; seven or eight in C. taroba ); 30–34 interopercular odontodes (vs. 12 or 13 in C. naipi ; 17–21 in C. mboycy and C. taroba ); 15–17 dorsal procurrent caudal-fin rays (vs. 25–29 in C. crassicaudata , C. igobi , C. mboycy , C. stawiarski , and C. taroba ; 30 or 31 in C. cauim ); 10 or 11 ventral procurrent caudal-fin rays (vs. 15 or 16 in C. naipi , 21–23 in C. taroba ); dorsal-fin origin at a vertical through the centrum of the 21 st or 22 nd vertebra (vs. 19 th or 20 th in C. crassicaudata , C. mboycy , and C. stawiarski ); jaw teeth pointed, irregularly arranged (vs. incisiform and arranged in rows in C. davisi ); and 39 vertebrae (36 in C. taroba ). Molecular diagnosis: 10 nucleotide substitutions, two of them unique among taxa analysed *: COX 1 105 (G → A), COX 1 252 (G → A), COX 1 360 (G → A), COX 1 462 (T → G) *, COX 1 534 (G → A), CYTB 69 (A → G) *, CYTB 195 (T → C), CYTB 219 (T → C), CYTB 483 (A → G), CYTB 637 (G → A). COX 1 p-distances among congeners of the Cambeva beta-clade ranging from 1.2 ( Cambeva atrobrunnea Costa, Feltrin & Katz , sp. nov., Cambeva cubataonis (Bizerril, 1994) , and Cambeva ventropapillata Costa, Feltrin & Katz, 2022 ) and 4.7.

Description.

Morphometric data appear in Table 6 .

Head morphology. Barbels moderate in length. Nasal barbel reaching area just posterior to orbit, maxillary and rictal barbels reaching middle of interopercular patch of odontodes. Jaw teeth with pointed to rounded extremities, irregularly arranged. Premaxillary teeth 37 or 38, dentary teeth 32–35 Opercular and interopercular odontodes pointed, about straight. Opercular odontodes 14–17, interopercular odontodes 30–34.

Fin morphology. Fins rounded. Total dorsal-fin rays 11 (ii + II + 7), total anal-fin rays 9 (ii + II + 5). Anal-fin origin at vertical through posterior portion of dorsal-fin base, at base of 6 th branched dorsal-fin ray in specimens above about 50 mm SL, at vertical through posterior middle of dorsal-fin base, at base of 4 th branched dorsal-fin ray in smaller specimens. Pectoral fin rounded in dorsal view, first pectoral-fin ray about equal in length to second ray, not forming terminal filament. Total pectoral-fin rays 7 (I + 6). Pelvic fin rounded, its tip reaching vertical through middle of dorsal-fin base. Total pelvic-fin rays 5 (I + 4). Caudal fin subtruncate, corners rounded. Total principal caudal-fin rays 13 (I + 11 + I), total dorsal procurrent rays 15–17 (xiv – xvi + I), total ventral procurrent rays 10 or 11 (ix – x + I).

Osteology (Fig. 4 J – L ). Mesethmoid broad anteriorly, with small lateral expansion in area just anterior to lateral ethmoid. Anterior mesethmoid margin convex, mesethmoid cornu broad, subtriangular, slightly curved posteriorly, abruptly narrowing at its extremity. Lateral ethmoid with small lateral projection immediately posterior to articular facet for autopalatine. Lacrimal thin, elliptical. Sesamoid supraorbital length about two times longer than lacrimal, without lateral expansions, its width about equal to lacrimal width. Premaxilla long, laterally narrowing, slightly curved. Maxilla slender, slightly curved, its length about four fifths of premaxilla, posterior process rudimentary. Autopalatine sub-trapezoidal in dorsal view, broad, its largest width about equal to its length, medial margin deeply sinuous with pronounced expansion on posterior margin, lateral margin weakly concave. Autopalatine postero-lateral process triangular, short, its length about half autopalatine length.

Metapterygoid sub-trapezoidal, longer than deep, relatively large, its surface greater than quadrate lateral surface. Area anterior to articulation between metapterygoid and quadrate with small laminar overlapped expansions of both bones. Quadrate with deep anterior constriction at dorsal process base. Hyomandibula long, anterior outgrowth horizontal length slightly longer than largest horizontal metapterygoid length. Dorsal margin of hyomandibula outgrowth concave. Opercle elongate, longer than interopercle. Opercular odontode patch moderately slender, its depth about two thirds of hyomandibula articular facet length. Dorsal process of opercle short, subtriangular, its extremity pointed. Opercular articular facet for hyomandibula with dorsal, small, rounded laminar projection, articular facet for preopercle rudimentary. Interopercle moderate in length, interopercular odontode patch length about equal hyomandibula outgrowth length. Preopercle slender, with minute ventral projection.

Parurohyal robust, lateral process sub-rectangular, slightly curved posteriorly, with truncate extremity. Parurohyal head with prominent anterolateral paired process. Parurohyal middle foramen relatively large, oval. Parurohyal posterior process short, about one third of distance between anterior margin of parurohyal and anterior insertion of posterior process. Branchiostegal rays 8 or 9. Vertebrae 39. Ribs 14 or 15. Dorsal-fin origin at vertical through centrum of 21 st or 22 nd vertebra; anal-fin origin at vertical through centrum of 25 th or 26 th vertebra. Two dorsal and single ventral hypural plate.

Colouration in alcohol. In adult specimens, above about 50 mm SL (Fig. 10 ), flank, dorsum and head side light brownish yellow, with great concentration of small dark brown to black dots. Venter and ventral surface of head pale yellow, with minute dark brown dots in area just anterior to pelvic fin and on branchiostegal region. Nasal and maxillary barbels brown, rictal barbel brownish white. Fins hyaline; dark chromatophores scattered over all fins, except pelvic fin. In juvenile specimens about 40 mm SL or less (Fig. 11 ), flank, dorsum and head side light brownish yellow with small black dots irregularly arranged.

Distribution.

Cambeva rotundipinna is known from two close localities in the Rio da Paca, a tributary of the Rio Jangada, Rio Iguaçu drainage, Rio Paraná basin, at about 1000 m asl (Fig. 5 ).

Etymology.

From the Latin rotundus (rounded) and pinna (fin or wing), an allusion to the rounded fins of this new species.

Figures

Figure 4. Osteological structures of: A – C. Cambeva galactica Costa, Feltrin & Katz, sp. nov.; D – F. Cambeva atrobrunnea Costa, Feltrin & Katz, sp. nov.; G – I. Cambeva luteoreticulata Costa, Feltrin & Katz, sp. nov., and J – L. Cambeva rotundipinna Costa, Feltrin & Katz, sp. nov. A, D, G, J. Mesethmoidal region and adjacent structures, left and middle portions, dorsal view; B, E, H, K. Left jaw suspensorium and opercular series, lateral view. C, F, I, L. Parurohyal, ventral view. Abbreviation of structure indicated by arrow: aes, anteromedial expansion of sesamoid supraorbital. Larger stippling represents cartilaginous areas.

Figure 5. Geographical distribution of four new species of Cambeva from the Rio Iguaçu drainage, Serra do Espigão, southern Brazil: 1. Cambeva galactica Costa, Feltrin & Katz, sp. nov.; 2. Cambeva atrobrunnea Costa, Feltrin & Katz, sp. nov.; 3. Cambeva luteoreticulata Costa, Feltrin & Katz, sp. nov.; 4. Cambeva rotundipinna Costa, Feltrin & Katz, sp. nov.

Figure 7. Cambeva atrobrunnea Costa, Feltrin & Katz, sp. nov., paratype, UFRJ 13821, 33.4 mm SL. A. Lateral view; B. Dorsal view; C. Ventral view.

Figure 10. Cambeva rotundipinna Costa, Feltrin & Katz, sp. nov., holotype, UFRJ 14070, 78.0 mm SL. A. Lateral view; B. Dorsal view; C. Ventral view.

Figure 11. Cambeva rotundipinna Costa, Feltrin & Katz, sp. nov., paratype, UFRJ 13820, 44.0 mm SL. A. Lateral view; B. Dorsal view; C. Ventral view.