Cambeva atrobrunnea Costa, Feltrin & Katz 2024, sp. nov.
Creators: name: Costa, Wilson J. E. M.
name: Feltrin, Caio R. M.
name: Mattos, José Leonardo O.
name: Katz, Axel M.
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Siluriformes
Trichomycteridae
Cambeva
Cambeva atrobrunnea

description: Cambeva atrobrunnea Costa, Feltrin & Katz sp. nov.
Figs 4 D – F, 6, 7, Table 4
Type material.
Holotype. Brazil • 70.1 mm SL; Santa Catarina State: Timbó Grande Municipality: stream tributary of Rio Timbó, Rio Iguaçu drainage, Rio Paraná basin; 26 ° 34 ' 41 " S, 50 ° 40 ' 28 " W; about 970 m asl; 29 Jun. 2023; C. R. M. Feltrin, leg; UFRJ 14066.
Paratypes. Brazil • 7 ex., 26.6–70.1 mm SL; same data as holotype; UFRJ 13821. • 2 ex. (C & S), 27.4–44.2 mm SL; same data as holotype; UFRJ 14067. • 2 ex., 29.9–46.8 mm SL. same locality and collector as holotype; 31 Mar. 2023; UFRJ 13553. • 3 ex. (DNA), 27.4–44.2 mm SL; same locality and collector as holotype; 31 Mar. 2023; UFRJ 13554.
Diagnosis.
Cambeva atrobrunnea is distinguished from all other congeners by having the two posterior-most dorsal and ventral procurrent caudal-fin rays segmented (vs. only the posterior-most ray segmented). Cambeva atrobrunnea is also distinguished from the two other species of western RISE, Cambeva luteoreticulata Costa, Feltrin & Katz, sp. nov. and Cambeva rotundipinna Costa, Feltrin & Katz, sp. nov., by having subtruncate caudal fin (vs. rounded), fewer interopercular odontodes (20–22 vs. 29–34), and specimens below about 40 mm SL having flank light grey with small black dots that are arranged in irregular rows, coalesced on the anterior portion of the longitudinal midline to form a stripe (Fig. 7 A; vs. pale yellow with large, irregularly shaped dark brown to black blotches, sometimes forming longitudinal stripes in the area between dorsum and flank in C. luteoreticulata Costa, Feltrin & Katz, sp. nov., and light brownish yellow with small black dots irregularly arranged in C. rotundipinna Costa, Feltrin & Katz, sp. nov. (see descriptions below); from C. luteoreticulata Costa, Feltrin & Katz, sp. nov. by specimens above 40 mm SL having the nasal barbel reaching area just anterior to opercle (vs. reaching area anterior to orbit), fewer ventral procurrent caudal-fin rays (13 or 14 vs. 15 or 16), and jaw teeth irregularly arranged (vs. arranged in three rows); and from C. rotundipinna Costa, Feltrin & Katz, sp. nov. by having more procurrent caudal-fin rays (21 dorsal and 13 or 14 ventral, vs. 15–17 and 10 or 11, respectively), and more opercular odontodes (12 vs. eight or nine). Cambeva atrobrunnea is also distinguished from all the remaining congeners from the Rio Iguaçu drainage by the following combination of character states: seven pectoral-fin rays (vs. eight in Cambeva castroi (de Pinna, 1992), Cambeva melanoptera Costa, Abilhoa, Dalcin & Katz, 2022, Cambeva crassicaudata (Wosiacki & de Pinna, 2008), Cambeva stawiarski (Miranda Ribeiro, 1968), and six in C. galactica, C. naipi, and C. taroba); absence of the anterior infraorbital (vs. presence in C. galactica, C. naipi, Cambeva papillifera (Wosiacki & Garavello, 2004), Cambeva plumbea (Wosiacki & Garavello, 2004), and C. taroba); posterior margin of the caudal fin slightly convex (vs. about straight in C. crassicaudata, C. davisi, C. galactica, C. melanoptera, C. papillifera, Cambeva piraquara dos Reis, Wosiacki, Ferrer, Donin & da Graça, 2022, C. plumbea, C. igobi (Wosiacki & de Pinna, 2008); straight to slightly concave in C. stawiarski; bilobed in C. crassicaudata; and emarginate in Cambeva cauim dos Reis, Ferrer & Graça, 2021); 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, C. galactica, and C. piraquara); 12 opercular odontodes (vs. broad, with 17 or 18 in Cambeva mboycy (Wosiacki & Garavello, 2004); 15 or 16 in C. davisi; seven or eight in C. taroba); 20–22 interopercular odontodes (vs. 12 or 13 in C. naipi); 21 dorsal procurrent caudal-fin rays (vs. 15–17 in C. castroi and C. melanoptera; 18 or 19 in C. naipi; 25–29 in C. crassicaudata, C. igobi, C. mboycy, C. stawiarski, and C. taroba; 30 or 31 in C. cauim); 13 or 14 ventral procurrent caudal-fin rays (vs. 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 or 40 vertebrae (36 in C. taroba). Molecular diagnosis: combination of 17 nucleotide substitutions, five of them unique among taxa analysed *, and four unique for the Cambeva beta-clade **: COX 1 216 (A → C) *, COX 1 249 (T → C), COX 1 252 (G → A), COX 1 471 (G → A), COX 1 534 (G → A), CYTB 108 (C → T), CYTB 186 (C → T) **, CYTB 237 (C → T) *, CYTB 360 (T → C) **, CYTB 378 (C → T) *, CYTB 442 (C → T) *, CYTB 765 (C → T), CYTB 909 (A → T) **, CYTB 942 (A → G), CYTB 960 (A → T) *, CYTB 994 (A → C). COX 1 p-distances among congeners of the Cambeva beta-clade ranging from 1.2 (Cambeva chrysornata Costa, Feltrin & Katz, 2022 and Cambeva rotundipinna Costa, Feltrin & Katz, sp. nov.) and 3.9.
Description.
Morphometric data appear in Table 4.
Head morphology. Barbels moderate in length. Nasal barbel reaching between orbit and opercular patch of odontodes, maxillary barbel reaching posterior portion of interopercular patch of odontodes, and rictal barbel reaching middle of interopercular patch of odontodes. Jaw teeth variable in shape, smaller teeth slightly pointed, larger teeth sub-incisiform with slightly rounded tip, irregularly arranged. Premaxillary teeth 39–41, dentary teeth 40. Opercular and interopercular odontodes pointed, about straight. Opercular odontodes 12; interopercular odontodes 20–22. Anterior infraorbital sensory canal absent.
Fin morphology. Dorsal and anal fins subtriangular, distal margin slightly convex. Total dorsal-fin rays 10 or 11 (ii + II – III + 6–7), total anal-fin rays 9 or 10 (ii + II + 5–6). Anal-fin origin at vertical just posterior to middle of dorsal-fin base, at base of 4 th branched dorsal-fin ray. Pectoral fin sub-triangular in dorsal view, margins slightly convex, first pectoral-fin ray shorter than second ray, not forming terminal filament. Total pectoral-fin rays 7 (I + 6). Pelvic fin rounded, its tip reaching vertical through anterior portion of dorsal-fin base. Total pelvic-fin rays 5 (I + 4). Caudal fin subtruncate, posterior margin weakly convex. Total principal caudal-fin rays 13 (I + 11 + I), total dorsal procurrent rays 21 (xix + II), total ventral procurrent rays 13 or 14 (xi – xii + II).
Osteology (Fig. 4 D – F). Mesethmoid broader anteriorly, without lateral expansions in its main axis, anterior mesethmoid margin slightly convex. Mesethmoid cornu extremity rounded. Lateral ethmoid with small lateral projection immediately posterior to articular facet for autopalatine and small, twisted expansion on anterior margin. Lacrimal narrow, short and thin. Sesamoid supraorbital rod-shaped, narrower than lacrimal, its longitudinal length about two times and half longer than lacrimal longitudinal length, without lateral expansions. Premaxilla long, laterally narrowing, slightly curved. Maxilla slender, with rudimentary posterior process, slightly curved, its length about three fourths of premaxilla. Autopalatine sub-trapezoidal in dorsal view, medial margin sinuous, lateral margin weakly concave. Autopalatine postero-lateral process triangular, short, its length about half autopalatine length excluding anterior cartilage. Autopalatine articulation for lateral ethmoid with laminar shovel-shaped expansion.
Metapterygoid sub-rectangular, longer than deep, relatively large, its surface greater than quadrate lateral surface. Areas anterior and posterior to cartilaginous articulation between metapterygoid and quadrate with small laminar overlapped expansions forming additional points of articulation. 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 slender, its depth about half hyomandibula articular facet length. Dorsal process of opercle short, subtriangular, its extremity rounded. Opercular articular facet for hyomandibula with dorsal, trapezoidal laminar projection, articular facet for preopercle small, rounded. Interopercle moderate in length, interopercular odontode patch length about equal hyomandibula outgrowth length. Preopercle slender, with minute ventral projection.
Parurohyal robust, lateral process subtriangular, slightly curved posteriorly, with pointed tip. Parurohyal head with prominent anterolateral paired process. Parurohyal middle foramen relatively large, oval. Parurohyal posterior process moderate in length, about half of distance between anterior margin of parurohyal and anterior insertion of posterior process. Branchiostegal rays 9. Vertebrae 39 or 40. 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 or one dorsal and single ventral hypural plate.
Colouration in alcohol. In adult specimens (Fig. 6), flank, dorsum, and head side light brownish yellow, with great concentration of small dark brown to black dots. Venter and ventral surface of head brownish white, with minute dark brown dots in area just anterior to pelvic fin. Nasal and maxillary barbels brown, rictal barbel brownish white. Fins hyaline, with minute dark brown dots on basal region of dorsal, anal and pectoral fins, and on whole caudal fin. In juvenile specimens below about 50 mm SL (Fig. 7), flank, dorsum and head side light grey, with small black dots arranged in irregular longitudinal rows, coalesced on anterior portion of longitudinal midline of flank to form black stripe.
Distribution.
Cambeva atrobrunnea is known from a single locality in a stream tributary of the Rio Timbó, Rio Iguaçu drainage, Rio Paraná basin, at about 970 m asl (Fig. 5).
Etymology.
From the Latin ater (dull black, dark) and brunneus (brown), referring to the predominant colour of the flank in adult specimens of the new species.
description: Published as part of 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, pp. 199-218 in Evolutionary Systematics 8 (2) on pages 199-218, DOI: 10.3897/evolsyst.8.126393