Austrolebias pongondo COSTA & MOREVY, 2017

Costa, Wilson, Cheffe, Morevy & Amorim, Pedro, 2017, Two new seasonal killifishes of the Austrolebias adloffi group from the Lagoa dos Patos basin, southern Brazil (Cyprinodontiformes: Aplocheilidae), Vertebrate Zoology 67 (2), pp. 139-149 : 144-146

Austrolebias pongondo COSTA & MOREVY sp. nov.

Fig 5 , Table 2

Holotype: UFRJ 9583 , male, 37.0 mm SL; Brazil: Estado do Rio Grande do Sul: Município de Pelotas:swamp at the road to Torotama island, Arraial , Povo Novo district, 31°55′54″S 52°14′42″W; M. CHEFFE et al., 21 Aug. 2001 .

Paratypes: All from Município de Pelotas, Estado do Rio Grande do Sul, southern Brazil: UFRJ 9584 , 2 males, 30.5– 34.4 mm SL, 6 females, 31.0– 37.0 mm SL; collected with holotype . – UFRJ 9585 , 3 males, 33.9 – 40.9 mm SL, 2 females, 33.1– 37.1 mm SL; same locality as holotype; M. CHEFFE et al., 15 Aug. 2001 . – CIMC 4540 , 8 males, 27.8– 35.9 mm SL, 7 females, 22.5 – 31.8 mm SL; swamp close to the road BR-392, localidade de Capão Seco, Povo Novo district, 31°55′21″S 52°18′47″W; M. CHEFFE et al., 30 Aug. 2000 . – CIMC 42098 , 12 males, 26.7– 36.1 mm SL, 21 females, 26.3 – 36.4 mm SL; road BR-392 , 31º54′59″S 52º18′53″W; M. BURNS & E. SILVEIRA, 18 Aug. 2011 . – CIMC 42099 , 20 males, 18.8 – 32.3 mm SL, 25 females, 14.5 – 30.7 mm SL; road BR-392 , 31º55′23″S 52º18′45″W; M. CHEFFE et al., 17 Aug. 2011 . – CIMC 42100 , 2 males, 30.8 – 33.2 mm SL, 16 females, 19.1– 35.3 mm SL; road BR-392 , 31º55′20″S 52º18′49″W; M. BURNS, 5 Oct. 2011 . – CIMC 42103 , 3 males, 30.5 – 34.5 mm SL, 3 females, 29.7– 34.2 mm SL; road BR-392 , 31º54′59″S 52º18′53″W; M. BURNS, 5 Oct. 2011 . – CIMC 42108 , 5 males, 29.4– 36.3 mm SL, 1 female, 31.2 mm SL; road BR-392 , 31º54′58″S 52º18′55″W; M. BURNS, 15 Sep. 2011 . – CIMC 42114 , 2 males, 31.9– 38.2 mm SL, 2 females, 29.0 – 32.7 mm SL; road BR-392 , 31º54′48″S 52º18′55″W; M. BURNS, 5 Oct. 2011 . – CIMC 42116 , 1 male, 30.6 mm SL, 8 females, 26.2 – 32.5 mm; Banhado do Cemitério , 31º55′23″S 52º18′46″W, Povo Novo district; M. BURNS, 5 Oct. 2011 . – UFRJ 8977 , 3 males, 25.8 – 31.8 mm SL, 3 females, 28.6 – 31.3 mm SL ( DNA); same locality as CIMC 42116; M. CHEFFE & M. BURNS, 22 Sep. 2011 . – CIMC 5666 , 1 male, 42.9 mm SL; swamp near Banhado da Mulata , 31°55′10″S 52°17′16″W; M. CHEFFE et al., 21 Aug. 2001 . – UFRJ 9581 , 12 males, 24.1– 30.9 mm SL, 35 females, 23.7 – 29.6 mm SL ; UFRJ 9582 , 2 males, 29.4– 31.5 mm SL, 3 females, 27.6 – 28.5 mm SL (C&S); swamp close to the road BR-392 , Capão Seco, 31°47′59″S 52°19′59″W; M. CHEFFE & M. BURNS, 30 Oct. 2000 . – CIMC 5671 , 5 males, 30.5 – 37.8 mm SL, 7 females, 30.1– 42.4 mm SL; same locality as UFRJ 9581; M. CHEFFE & F. SILVEIRA, 23 Aug. 2001 .

Austrolebias pongondo

UFRJ 8977.1 · Povo Novo · KJ475092 31º 55′ 23″S 52º 18′ 45″W

UFRJ 8977.2 · Povo Novo · KJ475093 31º 55′ 23″S 52º 18′ 45″W

UFRJ 8977.3 · Povo Novo · KJ475094 31º 55′ 23″S 52º 18′ 45″W

UFRJ 8977.4 · Povo Novo · KJ475095 31º 55′ 23″S 52º 18′ 45″W

Diagnosis. Austrolebias pongondo is distinguished from all other species of the A. adloffi group, except A. pelotapes , by the following combination of character states: a transverse row of small spots on the middle portion of the dorsal fin in males (vs. transverse row absent in all other species), unpaired fins with a single row of light blue spots on their basal portion in males, and with a distinctive dark grey zone on the posterior portion of the dorsal and anal fins (vs. multiple rows of blue dots and no distinctive dark grey zone in A. charrua and A. minuano ), and caudal peduncle in males predominantly dark brownish grey or dark grey to black, with narrow vertical light blue zones (vs. alternating dark grey and light blue bars, dark grey bars slightly wider, equal or narrower than light blue bars, in A. adloffi , A. nachtigalli , A. nigrofasciatus , A. reicherti ). Austrolebias pongondo is distinguished from A. pelotapes by the former having the urogenital papilla free from the anal fin in males (vs. basal portion of the urogenital papilla attached to the anterior margin of the anal fin); 20 – 21 neuromasts in the supraorbital series (vs. 14 – 19) and 24 – 27 neuromasts around orbit (vs. 22 – 23); the presence of dark grey to black bars on the flank strongly contrasting with the light blue interspace (vs. grey bars slightly contrasting with the light blue background in A. pelotapes ) and a row of blue dots on the basal portion of the caudal fin (vs. absence, sometimes a single dot).

Austrolebias pongondo is distinguished from all other species of the A. adloffi group by six unique nucleotide substitutions: cytb.568( G > T), cytb.581( T > G), cytb.641( A > G), cytb.643( G > A), cytb.648( T > C), cytb.750( G > C); it is similar to A. pelotapes and distinguished from all other congeners of the A. adloffi group by four unique nucleotide substitutions: cytb.357( T > C), cytb.393( C > T), cytb.580( A > G), cytb.660( C > T); it is also distinguished from A. pelotapes by the latter having five unique nucleotide substitutions: cytb.219( A > G), cytb.243( T > C), cytb.480( T > C), cytb.501( G > A), cytb.663( C > T). Other nucleotide loci useful to distinguish A. pongondo from A. pelotapes are: cytb.165( T), cytb.258( G), cytb.345( A), cytb.408( G), cytb.569( T) (vs. cytb.165( C), cytb.258( A), cytb.345( G), cytb.408( A), cytb.569( C) in A. pelotapes ).

Description. Morphometric data appear in Table 2 . Largest male examined 42.9 mm SL; largest female examined 42.4 mm SL. Dorsal and ventral profiles convex from snout to end of dorsal and anal-fin bases, nearly straight on caudal peduncle. Body deep and compressed, greatest body depth at vertical through pelvic-fin base. Jaws short, snout blunt. Urogenital papilla cylindrical and short in males, free from anal fin; urogenital papilla pocket-shaped in females, overlapping anal-fin origin.

Extremity of dorsal and anal fins rounded in both sexes. In females, anal fin sub-triangular with antero-median rays lengthened, distal portion thickened. Caudal fin rounded. Pectoral fin elliptical, posterior margin reaching vertical between base of 6 th and 7 th anal-fin rays in males, between base of 1 st and 3 rd anal-fin rays in females. Pelvic fin small, tip reaching base of 4 th anal-fin ray; medial membrane about 10 – 50 % coalesced. Dorsal-fin origin on vertical between base of 3 rd and 6 th anal-fin rays in males, between base of 1 st and 3 rd rays in females; second proximal radial of dorsal fin between neural spines of 8 th and 10 th vertebrae in males, between neural spines of 9 th and 12 th vertebrae in females; first proximal radial of anal fin between pleural ribs of 7 th and 9 th vertebrae in males, between pleural ribs of 8 th and 10 th vertebrae in females. Dorsal-fin rays 19 – 22 in males, 15 – 20 in females; anal-fin rays 22 – 25 in males, 19 – 23 in females; caudal-fin rays 22 – 23; pectoral-fin rays 11; pelvic-fin rays 4 – 5.

Scales large, cycloid. Trunk and head entirely scaled, except on infraorbital region and ventral surface of head. Body squamation extending over anterior 20 % of caudal-fin base; one irregular row of scale on middle portion of anal-fin base, no scales on dorsal-fin base. Frontal scales irregularly arranged; E-scales slightly overlapping medially. One or two supra-orbital scales. Longitudinal series of scales 27 – 28; transverse series of scales 11; scale rows around caudal peduncle 16. One to five minute contact organs on scales of antero-ventral part of flank in males; minute contact organs on internal surface of three uppermost pectoral-fin rays in males; no contact organs on unpaired and pelvic fins.

Cephalic neuromasts: supraorbital 20 – 21, parietal 3, anterior rostral 1, posterior rostral 1, infraorbital 2 – 3 + 24 – 27, preorbital 3, otic 3 – 4, post-otic 3 – 4, supratemporal 1, median opercular 1, ventral opercular 2 – 3, pre-opercular 22 – 28; mandibular 13 – 15 (pre-opercular plus mandibular 27 – 33), lateral mandibular 5 – 6, paramandibular 1. One neuromast per scale of lateral line. Two neuromasts on caudal-fin base.

Basihyal sub-triangular, basihyal cartilage about 40 % of total length of basihyal. Six branchiostegal rays. Second pharyngobranchial teeth 3. Gill-rakers on first branchial arch 3 + 10. Vomerine teeth absent. Dermosphenotic absent. Ventral process of posttemporal well-developed. Total vertebrae 27 – 29.

Colouration. Males. Flank usually with 7 – 10 dark grey to black bars separated by light blue interspace; anterior bars narrower, about equal in width or slightly wider than adjacent light blue interspaces, posterior bars 1.5 – 2 times wider than adjacent light blue bars. Urogenital papilla grey. Side of head light blue on opercular and infra-orbital region; dark grey infra-orbital bar, wider close eye, gradually narrowing ventrally; elongate black supra-orbital bar, with distinctive narrow extension over neuromast parietal series. Iris dark yellow, with dark black bar through centre of eye. Dorsal and anal fins dark bluish grey, darker near fin base, with few light blue dots and narrow bars parallel to fin rays on basal half of fin; transverse sub-basal row of light blue dots; black blotch, more visible in preserved specimens, on posterior portion of dorsal and anal fins, anteriorly limited by narrow oblique light blue bar. Caudal fin bluish grey, lighter on basal portion; transverse row light blue dots on fin base. Pelvic fin bluish grey. Pectoral fin hyaline with black ventral margin.

Females. Flank light brownish grey; grey marks variable in form, ranging from spots vertically elongated to bars, marks sometimes absent; venter silver; no black spot on anterocentral portion of flank; two black spots vertically arranged on posterior portion of caudal peduncle, often coalesced to form 8-shaped spot, sometimes absent. Opercular region pale blue. Iris light yellow, with grey bar through centre of eye. Infraorbital and supraorbital bars grey. Unpaired fins hyaline, with faint grey bars on basal portion of dorsal and anal fins; paired fins hyaline.

Genetic distance. To A. pelotapes : 2.7 – 3.6 %; to A. nigrofasciatus : 9.0 – 9.7 %; to A. adloffi : 4.2 – 5.3 %; to other species of the A. adloffi species group: 12.7 – 17.4 %; intraspecific: 0 – 0.7.

Distribution and habitat. Austrolebias pongondo is known only from temporary pools and swamps in the floodplains south of the São Gonçalo channel, Povo Novo, Rio Grande, Rio Grande do Sul state, southern Brazil. The several pools and swamps of this area were significantly reduced after duplication of the road BR-392 between 2011 and 2012. Consequently, at least material CIMC 4595, CIMC 5671, CIMC 42098, CIMC 42099, CIMC 42100, CIMC 42103, CIMC 42108 and CIMC 42114 refer to pools today extinct. Considering the small area of distribution and the intense recent decline of the resting populations, A. pongondo should be indicated to be listed among the critically endangered species of southern Brazil.

Etymology. The name pongondó is the local designation for the people living in the village of Povo Novo, Rio Grande municipality, to where the new species is endemic.

Figures

Fig. 5. Austrolebias pongondo, UFRJ 9583, holotype, male, 37.0 mm SL; Brazil: Rio Grande do Sul: Pelotas.