Dendrophryniscus izecksohni, Cruz & Caramaschi & Fusinatto & Brasileiro, 2019

Cruz, Carlos Alberto Gonçalves, Caramaschi, Ulisses, Fusinatto, Luciana Ardenghi & Brasileiro, Cinthia Aguirre, 2019, Taxonomic review of Dendrophryniscus brevipollicatus Jiménez de la Espada, 1870, with revalidation of D. imitator (Miranda-Ribeiro, 1920) and D. lauroi Miranda-Ribeiro, 1926, and description of four new related species (Anura, Bufonidae), Zootaxa 4648 (1), pp. 27-62 : 48-50

Dendrophryniscus izecksohni sp. nov.

( Figs 13–14 )

Holotype. MZUSP 103536 , adult male, collected at Campo de Fruticultura da Bocaina (currently Núcleo Senador Vergueiro), Municipality of São José do Barreiro (22 o 38’S, 44 o 34’W, Datum WGS 84, 540 m altitude), State of São Paulo, Brazil, by F. M. Oliveira, O. Oliveira and W.C.A. Bokermann, in November 1968.

Paratypes. All specimens collected at type locality : MNRJ 2416 , adult female, collected by J.L.A. Feio and P. Miranda-Ribeiro, no date ; MZUSP 103516 , 103517 , adult males , MZUSP 103518 , MZUSP 103519 , adult male, collected by F.M. Oliveira, O. Oliveira, C.A. Seabra and W.C.A Bokermann, in November 1965 ; MZUSP 103520 , adult male , MZUSP 103537 , 103538 , adult females , MZUSP 103539 , 103541 , adult males , MZUSP 103542 , juvenile male , MZUSP 103543 , adult male , MZUSP 103544 , 103545 , juvenile males, collected with the holotype; MZUSP 79104 , 78508 , juvenile males, collected, by F.M. Oliveira, O. Oliveira e W.C.A. Bokermann, from October to November 1968 .

Diagnosis. The species is characterized by: (1) medium size for the genus ( SVL 19.4–24.6 mm in males, 19.6– 24.2 mm in females); (2) body slender; (3) snout mucronate in dorsal view; (4) canthus rostralis slightly curved; (5) elliptical set of pronounced granules posterior to the corner of mouth; (6) surfaces of upper eyelid with few granules and with a conspicuous margin; (7) tip of the third and fourth fingers poor or not expanded laterally; (8) skinfold poor developed on the articulation of the first phalange of the fingers II, III, and IV; (9) male with large white nuptial pad with minuscule light brown horny asperities on finger I; (10) fingers fringed and webbed about one third.

Comparisons with other species. Dendrophryniscus izecksohni sp. nov. is distinguished from D. proboscideus by the smaller size ( SVL 19.4–24.6 mm in males of D. izecksohni sp. nov.; SVL 39.2–46.4 mm in males of D. proboscideus ); D. izecksohni sp. nov. is distinguished from D. krausae and D. stawiarskyi by the body with uniform shape (enlarged posteriorly in those species); D. izecksohni sp. nov. is distinguished from D. berthalutzae , D. carvalhoi , D. krausae , D. lauroi , D. oreites , D. proboscideus , D. skuki , and D. stawiarskyi by the snout mucronate in dorsal view (snout rounded in D. berthalutzae , D. carvalhoi , D. lauroi , and D. stawiarskyi ; snout truncate in dorsal view in D. krausae , D. oreites , and D. proboscideus ; snout long, narrow, spatulate, with parallel lateral borders and rounded tip in D. skuki ); by the canthus rostralis slightly curved, D. izecksohni sp. nov. is distinguished from D. davori sp. nov., D. carvalhoi , D. krausae , D. lauroi , and D. stawiarskyi (canthus rostralis straight); D. izecksohni sp. nov. presents an elliptical set of pronounced granules posterior to the corner of mouth (elliptical set of unpigmented shallow granules posterior to the corner of mouth in D. lauroi ; elliptical set of white, pronounced granules in D. brevipollicatus and D. jureia sp. nov.; longitudinal set in D. berthalutzae , D. krausae , D. leucomystax , and D. oreites ; two pronounced granules in D. imitator ; absent in D. carvalhoi , D. haddadi , D. organensis , D. probosci- deus, D. skuki , and D. stawiarskyi ); D. izecksohni sp. nov. presents the surfaces of upper eyelid with few granules sparse and external margin conspicuous (surfaces of upper eyelid with numerous granules and with the external margin slightly prominent in D. lauroi ; surfaces of upper eyelid with numerous granules densely distributed and with a conspicuous margin in D. brevipollicatus ; D. izecksohni sp. nov. is distinguished from D. brevipollicatus and D. lauroi by the tip of the third and fourth fingers poorly or not expanded (laterally expanded in those species); D. izecksohni sp. nov. is distinguished from D. brevipollicatus by the presence of a skinfold poorly developed on the articulation of the first and second phalanges of the fingers II, III, and IV (well developed in this species); D. izecksohni sp. nov. is distinguished from all species of the genus, except D. davori sp. nov., D. carvalhoi , D. leu- comystax, and D. stawiarskyi by the presence of large nuptial pad in male (absent in D. leucomystax , moderate in all other species; D. izecksohni sp. nov. is distinguished from D. brevipollicatus , D. haddadi , D. krausae , and D. lauroi by fingers fringed and webbed about one third (slightly fringed and webbed only at base in D. brevipollicatus ; fingers not fringed and webbed only at base in D. krausae ; and fingers not fringed nor webbed in D. berthalutzae , D. carvalhoi , D. haddadi , D. imitator , D. lauroi , D. oreites , D. skuki , and D. stawiarskyi .

Description of holotype. Body slender, elongated ( Fig. 13 ); head triangular, longer than large, head length 33.5% of SVL; snout mucronate in dorsal view, acute in lateral view ( Fig. 14 ); snout 45.9% of head length; presence of a small tubercle under the tip of snout in ventral view; nostrils not protuberant, small and elliptical, located laterally near the tip of snout, below and leaning the canthus rostralis; internarial distance 52.9% of eye to snout distance; eye diameter 64.7% of eye to snout distance and 73.3% of interorbital distance; eye protuberant; canthus rostralis slightly curved; loreal region vertical; choanae small, circular, and very far from witch one; tongue long, narrow, and few enlarged posteriorly; vocal sac indistinct; vocal slits present. Arms robust, forearms more robust than upper arms; hand with fingers slender, fringed and webbed about one third; tip of the third and fourth finger poorly expanded laterally; finger I enlarged, covered by large white nuptial pad with minuscule light brown horny asperities; relative lengths of fingers I< II < IV < III; subarticular tubercles single, rounded, except at the third subarticular tubercles of fingers II and III where they are horizontally elliptical; outer metacarpal tubercle large, rounded; inner metacarpal tubercle rounded, approximated a quarter of the outer metacarpal tubercle; few, supernumerary tubercles absent; skinfold poor developed on the articulation of the first phalanges of the fingers II, III, and IV. Thigh length as large as tibia length; sum of thigh and tibia lengths about 83.5% of snout vent length. Tarsal length 22.5% of the snout vent length. Foot with toes slender, not fringed; interdigital webbing developed, webbing formulae: I1– 1II1–2III1–3 - IV3 - – 2 - V; distal end of toes globose, not expanded laterally, relative lengths of toes I< II < III <V< IV; subarticular tubercles single, rounded, the same size of those of the fingers; outer metatarsal tubercle rounded, twice the size of subarticular tubercle; inner metatarsal like the outer; few, small and sparse supernumerary tubercles. Dorsal, ventral, and lateral surfaces covered by small and shallow spinulose granules irregularly distributed; surfaces of upper eyelid with few granules sparse and external margin poorly marked; external margin of tibia and tarsus smooth.

Color in preservative. Dorsal surfaces grayish brown; poorly defined brown transversal bar on thigh, tibia, and tarsus; ventral surface whitish, with numerous irregular brown marbling.

Measurements of holotype. SVL 21.3; HL 7.4; HW 6.2; IND 1.8; ESD 3.4; ED 2.2; IOD 3.0; THL 8.9; TL 8.9; TAL 4.8; FL 8.8.

Variation. Specimens are congruent with respect to the morphological characters. Variation of measurements and descriptive statistics of males and females are presented in Tables 2 and 3. Some specimens present on the dorsum an ‘X’ shaped brown blotch on the scapular region and an inverse ‘Y’ shaped brown blotch on the sacral region extending to the inguinal region. Sexual dimorphism can be observed on arms (slightly more robust in males), finger I (enlarged in males), and nuptial pad (on finger I of male).

Distribution. Dendrophryniscus izecksohni is known only from the type locality ( Fig. 17 ), Campo de Fruticultura (about 600 m above sea level), Municipality of São José do Barreiro, State of São Paulo, Brazil.

Natural history. Unknown.

Etymology. The name of the species honors the late Dr. Eugenio Izecksohn, from Universidade Federal Rural do Rio de Janeiro ( UFRRJ), our special friend and one of the most important Brazilian herpetologists.

Figures

FIGURE 13. Dendrophryniscus izecksohni sp. nov., holotype, MZUSP 103536 (SVL 21.3 mm). Dorsal and ventral views.

FIGURE 14. Dendrophryniscus izecksohni sp. nov., holotype, MZUSP 103536 (SVL 21.3 mm). Dorsal and lateral views of head, ventral views of hand and foot.

FIGURE 17. Map of geographic distribution of species of Dendrophryniscus brevipollicatus group reviewed in this study. RJ, State of Rio de Janeiro; SP, State of São Paulo.