Cambeva galactica 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 galactica Costa, Feltrin & Katz sp. nov.

Figs 2 , 3 , 4 A – C , Table 3

Type material.

Holotype. Brazil • 1 ex., 76.9 mm SL; Santa Catarina State: Rio Negrinho Municipality: village of Volta Grande: stream tributary of Rio Preto, itself a tributary of Rio Negro, Rio Iguaçu drainage, Rio Paraná basin ; 26 ° 33 ' 04 " S, 49 ° 40 ' 14 " W; about 970 m asl; 29 Mar. 2023; C. R. M. Feltrin, leg.; UFRJ 14064 .

Paratypes. Brazil • 4 ex., 18.7–40.6 mm SL; same data as for holotype; UFRJ 13516 . • 3 ex. (C & S), 40.5–64.9 mm SL; same data as for holotype; UFRJ 14065 . • 2 ex. (DNA), 16.5–38.8 mm SL; same data as for holotype; UFRJ 13517 . • 5 ex., 28.8–108.0 mm SL; same locality and collector as holotype; 28 Jun. 2023; UFRJ 13847 .

Diagnosis.

Cambeva galactica is distinguished from all congeners by a unique colour pattern in adult specimens consisting of flank and dorsum with longitudinal rows of interconnected yellowish white vermiculate diffuse marks (vs. never a similar colour pattern), and the presence of a distinctive projection on the anterior portion of the medial margin of the sesamoid supraorbital, connected by thin ligamentous tissue to a dorsal projection on the articulatory shell of the autopalatine for the lateral ethmoid (Fig. 4 A ; vs. never a similar process connected to that articulation). Cambeva galactica is also distinguished from all other species of the Cambeva beta-clade, except Cambeva flavopicta Costa, Feltrin & Katz, 2020 , Cambeva naipi ( Wosiacki & Garavello, 2004) , Cambeva taroba ( Wosiacki & Garavello, 2004) , and Cambeva tourensis Costa, Feltrin & Katz, 2023 by having six pectoral-fin rays (vs. five, seven, or eight). Cambeva galactica is distinguished from C. flavopicta and C. tourense by having well-developed pelvic fins (vs. absent); from C. naipi and C. taroba by having more interopercular odontodes 29–32 vs. 11 or 12 in C. naipi and 17–21 in C. taroba ) and more jaw teeth (41–43 on the premaxilla and 39–46 on the dentary, vs. 25–34 and 23–32, respectively); from C. naipi by having 14 or 15 ribs (vs. 12 or 13), fewer opercular odontodes (eight or nine vs 12 or 13), and from C. taroba by having a minute pectoral-fin filament, its length less than 5 % of the pectoral-fin length (vs. about 20 %), fewer procurrent caudal-fin rays (18 or 19 dorsal and 12 or 13 ventral, vs. 26 or 27 and 21–23, respectively), more vertebrae (39 or 40 vs 36). Molecular diagnosis: 34 nucleotide substitutions, nine of them unique among taxa analysed *, and five unique for the Cambeva beta-clade **: COX 1 103 (T → C) **, COX 1 103 (G → A), COX 1 117 (A → T) *, COX 1 243 (A → G) *, COX 1 309 (G → A), COX 1 312 (C → A), COX 1 321 (C → A), COX 1 330 (C → A) *, COX 1 483 (T → C), COX 1 540 (A → G), COX 1 547 (C → T), COX 1 684 (A → C) *, CYTB 195 (T → C), CYTB 219 (T → C), CYTB 282 (C → T) **, CYTB 283 (T → C), CYTB 339 (C → T), COX 1 342 (C → T), CYTB 394 (C → T), CYTB 399 (T → C) **, CYTB 495 (G → A), CYTB 528 (A → G), CYTB 585 (T → C) **, CYTB 711 (C → T) *, CYTB 715 (G → A) *, CYTB 735 (C → T) *, CYTB 771 (C → T) *, CYTB 822 (A → G), CYTB 849 (T → C), CYTB 891 (T → C) *, CYTB 900 (T → C) *, CYTB 909 (A → G), CYTB 994 (A → C), CYTB 1032 (C → T) **. COX 1 p-distances among congeners of the Cambeva beta-clade ranging from 2.9 ( Cambeva atrobrunnea Costa, Feltrin & Katz , sp. nov. and Cambeva ventropapillata Costa, Feltrin & Katz, 2022 ) and 4.7.

Description.

Morphometric data appear in Table 3 .

Head morphology. Barbels moderate in length. Nasal barbel reaching area just anterior to opercle, maxillary barbel reaching between interopercular patch of odontodes and pectoral-fin base, and rictal barbel reaching posterior portion of interopercular patch of odontodes. Jaw teeth pointed, irregularly arranged. Premaxillary teeth 41–43, dentary teeth 39–46. Opercular and interopercular odontodes pointed, about straight. Opercular odontodes 8 or 9; interopercular odontodes 29–32. Anterior infraorbital sensory canal present.

Fin morphology. Dorsal and anal fins subtriangular, margins slightly convex. Total dorsal-fin rays 11 or 12 (ii – iii + II – III + 6–7), total anal-fin rays 9 or 10 (ii – iii + II + 5). Anal-fin origin at vertical just posterior to middle dorsal-fin base, at base of 3 rd or 4 th branched dorsal-fin ray. Pectoral fin sub-triangular in dorsal view, margins slightly convex, first pectoral-fin ray slightly longer than second ray, weakly extending beyond fin membrane forming minute filament. Total pectoral-fin rays 6 (I + 5). Pelvic fin rounded, its tip reaching vertical through middle portion 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 18 or 19 (xvii – xviii + I), total ventral procurrent rays 12 or 13 (xi – xii + I).

Osteology (Fig. 4 A – C ). Mesethmoid narrow anteriorly, with lateral expansion in area just anterior to lateral ethmoid, anterior mesethmoid margin slightly concave, with minute anterior projection on its middle portion. Mesethmoid cornu extremity pointed. Lateral ethmoid with small lateral projection immediately posterior to articular facet for autopalatine. Anterodorsal portion of lateral ethmoid widened, projecting laterally. Lacrimal thin, elliptical. Sesamoid supraorbital gently curved, its longitudinal length about two times and half longer than lacrimal longitudinal length, its largest width about equal to lacrimal width. Medial margin of anterior portion of sesamoid supraorbital with distinctive projection, connected by thin ligamentous tissue to dorsal projection on articulatory shell of autopalatine for lateral ethmoid. Premaxilla long, laterally narrowing. Maxilla slender, with rudimentary posterior process, slightly curved, its length about four fifths 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.

Metapterygoid trapezoid, deeper than long, large, its surface about twice quadrate lateral surface. Quadrate with deep anterior constriction at dorsal process base. Hyomandibula long, anterior outgrowth horizontal length longer than largest horizontal metapterygoid length. Posterior margin of hyomandibula with small projection just above articular facet for opercle. Dorsal margin of hyomandibula outgrowth concave. Opercle elongate, longer than interopercle. Opercular odontode patch very slender, its depth about one third hyomandibula articular facet length. Dorsal process of opercle short, subtriangular, its extremity rounded. Opercular articular facet for hyomandibula with dorsal, rounded laminar projection. Articular facet for preopercle rounded, well-developed. Interopercle relatively long, interopercular odontode patch length longer than hyomandibula outgrowth length. Preopercle slender, with minute ventral projection.

Parurohyal thin, lateral process narrow, slightly curved posteriorly, with rounded extremity. Parurohyal head with prominent anterolateral paired process. Parurohyal middle foramen small, rounded. Parurohyal posterior process moderate in length, about three fourths of distance between anterior margin of parurohyal and anterior insertion of posterior process. Branchiostegal rays 8. 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 21 st or 22 nd vertebra. Two dorsal and single ventral hypural plate.

Colouration in alcohol. In adult specimens (Fig. 2 ), flank, dorsum, and head side pale brown; three longitudinal rows of interconnected yellowish white, diffuse, vermiculate marks: row on dorsum, with marks forming reticulate pattern along pre-dorsal midline; one row on dorsal portion of flank, comprising minute marks; and row on ventral portion of flank. Venter and ventral surface of head yellowish white. Barbels pale brown. Fins greyish hyaline. In juvenile specimens between about 25 and 50 mm SL (Fig. 3 ), flank and dorsum pale yellow, with broad dark brown stripe along flank longitudinal midline and dark brown reticulate pattern on dorsum, and dorsal and ventral portions of flank. In juvenile specimens smaller than 20 mm SL, flank and dorsum pale yellow, with narrow black stripe along flank longitudinal midline and longitudinal series of black blotches between dorsum and flank, and longitudinal series of small black dots on ventral portion of flank.

Distribution.

Cambeva galactica is only known from its type locality in the upper Rio Preto drainage, which is a tributary of the Rio Negro, Rio Iguaçu drainage, Rio Paraná basin, at about 970 m asl (Fig. 5 ).

Etymology.

The name galactica is derived from the Ancient Greek word galaktikós meaning milky, an allusion to the rows of yellowish white diffuse vermiculate marks present in the flank of the new species, reminiscent of the Milky Way.

Figures

Figure 2. Cambeva galactica Costa, Feltrin & Katz, sp. nov., holotype, UFRJ 14064, 76.9 mm SL. A. Lateral view; B. Dorsal view; C. Ventral view.

Figure 3. Cambeva galactica Costa, Feltrin & Katz, sp. nov., paratype, UFRJ 13847, 33.4 mm SL. A. Lateral view; B. Dorsal view; C. Ventral view.

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.