Cynopoecilus feltrini Costa, Amorim & Mattos 2016

Costa, Wison JEM, Amorim, Pedro F & Mattos, Jose Leonardo Oliveira, 2016, A new species of inseminating seasonal killifish of the Cynopoecilusmelanotaenia complex from southern Brazil (Cyprinodontiformes: Rivulidae), Biodiversity Data Journal 4, pp. 6888-6888 : 6888

Cynopoecilus feltrini Costa, Amorim & Mattos 2016 sp. n.

Materials

Type status: Holotype. Location: country: Brazil; stateProvince: Santa Catarina; county: Laguna; locality: temporary pool near the confluence of Tubarao river and the Santo Antonio lagoon ; verbatimElevation: 5 m; verbatimLatitude: 28°30'26"S; verbatimLongitude: 48°48'01"W; verbatimCoordinateSystem: degrees minutes seconds; verbatimSRS: Córrego Alegre; Event: year: 2015; month: 6; day: 10; habitat: Temporary pool; fieldNotes: collectors = C. Feltrin et al.; Record Level: institutionCode: UFRJ; collectionCode: 10662; basisOfRecord: PreservedSpecimen; dynamicProperties: sex=male, SL= 45.6 mm Type status: Paratype. Record Level: institutionID: UFRJ; collectionID: 10597; basisOfRecord: Preserved Specimen; dynamicProperties: 11 males, 18.2-48.0 mm SL, 11 females, 23.8-35.1 mm SL. Collected with holotype. Type status: Paratype. Record Level: institutionCode: UFRJ; collectionCode: 10598; basisOfRecord: Preserved Specimen; dynamicProperties: 3 males, 32.3-35.9 mm SL, 3 females, 22.5-34.1 mm SL. Collected with holotype. Type status: Paratype. Record Level: institutionCode: UFRJ; collectionCode: 10482; basisOfRecord: Preserved Specimen; dynamicProperties: 3 males, 20.3-32.2 mm SL, 2 females, 24.7-25.2 mm SL. Collected with holotype. Type status: Paratype. Event: year: 2015; month: 6; day: 4; Record Level: institutionCode: UFRJ; collectionCode: 10620; basisOfRecord: Cleared and Stained; dynamicProperties: 5 males, 27.9-46.9 mm SL, 2 females, 25.6-32.7 mm SL. Same locality of holotype.

Description

Morphometric data appear in Table 2. Largest male examined 48.0 mm SL; largest female examined 35.3 mm SL. Dorsal and ventral profiles slightly convex between snout and posterior end of dorsal and anal fins, nearly straight on caudal peduncle Fig. 1. Body slender, greatest body depth in vertical through pelvic-fin insertion. Urogenital papilla wide, with transverse opening projected over anal-fin origin. Longitudinal series of scales 27-28; transverse series of scales 9; scale rows around caudal peduncle 12. Contact organs on scales of caudal peduncle in males. Total vertebrae 29-30.

Eye positioned on dorsal portion of head side. Snout short, blunt. Premaxilla and dentary teeth conical, small, numerous, irregularly arranged, except for external series with longer fang-like teeth, slightly more robust in males. Vomerine teeth absent. Dermosphenotic absent. Frontal squamation usually E-patterned, sometimes D-patterned; E-scales often overlapping medially Fig. 2. Cephalic neuromasts: supraorbital 3 + 10 + 1, parietal 2, anterior rostral 1, posterior rostral 1, infraorbital 2-3 + 19-24, preorbital 4-6, otic 1, post-otic 2, supratemporal 1, pre-opercular 17-18, median opercular 1, ventral opercular 2-3, mandibular 8-10, lateral mandibular 7, paramandibular 1. Gill-rakers on first branchial arch 2 + 9. Six branchiostegal rays.

Dorsal and anal fins pointed in males, rounded in females; caudal fin rounded in both sexes; often short filamentous ray on tip of dorsal and anal fins, and minute posterior filamentous extension on middle of caudal fin in males. No scales on dorsal and anal fins, scales extending on about 30 % of caudal fin. Four to six neuromasts on caudal-fin base. Pectoral fin rounded, posterior margin reaching vertical between anus and urogenital opening in males, shorter, not reaching pelvic-fin base in females. No scales on pectoral-fin base. Pelvic-fin small, tip reaching between anus and urogenital opening in males, not reaching anus in females; pelvic-fin bases medially in close proximity. Dorsal-fin origin in vertical just anterior to anal-fin origin. Dorsal-fin origin between neural spines of vertebrae 12 and 13; anal-fin origin between pleural ribs of vertebrae 10 and 12 in males, between pleural ribs of vertebrae 12 and 13 in females. Hypurals forming single plate. Ventral process of posttemporal absent. Dorsal-fin rays 18-19; anal-fin rays 25-27; caudal-fin rays 29-32; pectoral-fin rays 13-15; pelvic-fin rays 5-7. No contact organ on fins.

Colouration. Males: Side of body pale brown to light yellowish brown, lighter on ventral portion; broad dark reddish brown to black stripe between posterior orbital margin and caudal-fin base, other similar narrower stripe between pectoral-fin base and posterior portion of anal-fin base; longitudinal rows of greenish blue to greenish golden spots, consisting of one spot per scale, on head side and flank, sometimes interrupted or rudimentary. Dorsum pale brown, with few dark brown spots above opercular region. Ventral portion of head and venter white. Lower jaw dark reddish brown. Few dark reddish brown on suborbital region. Branchiostegal membrane orangish red. Iris yellow, with dark reddish brown bar on middle, anterior and posterior portion with greenish golden iridescence. Unpaired fins pale grey; small dark grey spots on basal region of dorsal fin; light blue iridescence on margins of caudal and anal fins. Pectoral fin hyaline. Pelvic fin pale grey.

Females: Colour pattern similar to that described for males, but iridescent colour paler, median stripe often forming row of dark brown or black blotches, and faint grey dots present on basal portion of anal fin.

Diagnosis

Distinguished from all other species of the Cynopoecilus melanotaenia complex by having frontal E-scales medially overlapped (vs. separated by interspace), branchiostegal region orangish red in males (vs. hyaline to pinkish hyaline), dorsum with few dark brown spots above opercular region (vs. dark brown spots over most region between snout and dorsal-fin origin).

Etymology

Named after Caio Feltrin, in recognition of his dedication in inventorying the fish fauna of southern Brazil.

Distribution

Known only from the type locality area, in temporary pools in the floodplains of the Tubarão river, Santa Catarina state, southern Brazil, corresponding to the northern-most record for the genus Cynopoecilus (Fig. 3).

Taxon discussion

Cynopoecilus feltrini is easily identifiable by some morphological characters. Among them, the frontal squamation pattern consisting of E-scales medially overlapped is unique among cynopoeciline killifishes, which have been diagnosed by the E-scales medially separated by an interspace ( Costa 1998). Another striking feature of C. feltrini is the orangish red branchiostegal region in males, a condition not found in other congeners of the C. melanotaenia complex, but similar to the red branchiostegal region of C. notabilis ( Ferrer et al. 2014). Finally, all species of the C. melanotaenia complex may be easily recognised among other cynopoecilines by the presence of numerous dark brown spots along the dorsum, but in C. feltrini these spots are restricted to region above the opercular region.

Cynopoecilus feltrini is presently known only from the lower Tubarão river basin, which is the northern-most record of the genus. The phylogenetic tree supports C. feltrini as a member of the clade that includes all species of the C. melanotaenia complex except C. melanotaenia , which is the taxon endemic of an area corresponding to the southern-most region of the genus distribution (Figs 3, 4). The analysis also supports sister-group relationships between C. feltrini and a clade comprising C. fulgens , from the coastal plains between the Patos lagoon and the sea, and C. nigrovittatus , from the lower Jacuí river drainage (Figs 3, 4). In addition, all the lineages corresponding to the four species of the C. melanotaenia complex sampled in this study had high bootstrap values in the analysis, this corroborating morphological data ( Costa 2002, the present study). Cynopoecilus intimus , endemic of the upper Jacuí river basin, still has its phylogenetic position undetermined, since it was the only species of the C. melanotaenia complex not sampled for molecular data and morphological data alone do not provide unambiguous evidence about its position. In addition to diagnostic characters distinguishing C. feltrini from all other congeners discussed above, C. feltrini is easily distinguished from C. intimus by the latter having large dark brown blotches on the flank immediately below the dorsal-fin base (vs. blotches absent in C. feltrini ) and having minute pelvic fin in males, pelvic-fin length 4.7-5.6 % SL, its tip reaching anus or shorter (vs. 5.9-7.3 % SL in C. feltrini , pelvic-fin tip reaching space between anus and urogenital opening).