Dendrophryniscus imitator ( Miranda-Ribeiro, 1920 ) 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 : 34-38

Dendrophryniscus imitator ( Miranda-Ribeiro, 1920) , new status, revalidated

( Figs. 3–5 )

Atelopus imitator Miranda-Ribeiro, 1920 .

Dendrophryniscus brevipollicatus imitator— Miranda-Ribeiro 1926.

Dendrophryniscus brevipollicatus— Cochran 1955 (part); Heyer et al. 1990; Izecksohn 1994 (part); Malagoli et al. 2017.

Lectotype. MZUSP 847 , adult female ( Fig. 3 ), collected at Alto da Serra (23 o 46’S, 46 o 19’W, Datum WGS 84, 800 m altitude), Municipality of Paranapiacaba , State of São Paulo, Brazil, by Bicego in 1899.

Miranda-Ribeiro (1920) described Atelopus imitator based on five syntypes ( MZUSP 477 and 485 from Cubatão, Santos; MZUSP 947, Alto da Serra; MZUSP 835, Rio Grande; MZUSP 639, Campo Grande; all localities in the State of São Paulo). However, he described and referred measurements for one specimen (Corpo 23 mm., perna 28.), which matches the specimen MZUSP 847. This specimen is here designated lectotype for Atelopus imitator Miranda-Ribeiro, 1920 (currently Dendrophryniscus imitator ).

Currently, the color of the lectotype is fade because the time of preservation, and the body surfaces are homogeneous pale brown, the dorsal blotches not visible.

Measurements of lectotype. SVL 21.5; HL 7.4; HW 6.5; ED 2.4; THL 8.0; TL 8.9; TAL 4.8; FL 7.4.

Diagnosis. The species is characterized by: (1) medium size for the genus ( SVL 15.1–17.4 mm in males, 14.4–21.5 mm in females); (2) body slender; (3) snout mucronate in dorsal view; (4) canthus rostralis slightly curved; (5) presence of two pronounced granules posterior to the corner of mouth; (6) surfaces of upper eyelid with few granules sparse and external margin prominent; (7) tip of the third and fourth fingers poorly or not expanded laterally; (8) skinfold poor developed on the articulation of the first and second phalanges of the fingers II, III, and IV (9) male with moderate nuptial pad with minuscule horny unpigmented asperities on finger I; (10) fingers not fringed nor webbed.

Comparisons with other species. Dendrophryniscus imitator is distinguished from D. proboscideus by the smaller size ( SVL 15.1–17.4 mm in males of D. imitator ; SVL 39.2–46.4 mm in males of D. proboscideus ); D. imitator is distinguished from D. krausae and D. stawiarskyi by the slender body with uniform shape (robust and enlarged posteriorly in those species); D. imitator 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. imitator is distinguished from D. davori sp. nov., D. carvalhoi , D. krausae , D. lauroi , and D. stawiarskyi (canthus rostralis straight); the presence of two white pronounced granules posterior to the corner of mouth distinguishes D. imitator from D. lauroi (elliptical set of unpigmented shallow granules posterior to the corner of mouth), D. brevipollicatus (elliptical set of white pronounced granules), and D. berthalutzae , D. krausae , D. leucomystax , and D. oreites (longitudinal set); D. carvalhoi , D. haddadi sp. nov., D. organensis , D. proboscideus , D. skuki , and D. stawiarskyi (set absent); D. imitator presents the surfaces of upper eyelid with few granules sparse and external margin prominent (surfaces of upper eyelid with numerous granules densely distributed and with a conspicuous margin in D. brevipollicatus and D. izecksohni sp. nov.; surfaces of upper eyelid with numerous granules with the external margin slightly prominent in D. lauroi ; surfaces of upper eyelid with few granules sparse and external margin conspicuous in D. davori sp. nov.); D. imitator is distinguished from D. brevipollicatus , D. lauroi , and D. organensis by the tip of the third and fourth fingers poorly or not expanded laterally (laterally expanded in those species); D. imitator 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. imitator is distinguished from D. davori sp. nov., D. carvalhoi , D. izecksohni sp. nov., D. leucomystax , and D. stawiarskyi by the presence of moderate nuptial pad in male (absent in D. leucomystax ; very developed in D. davori sp. nov., D. carvalhoi , D. izecksohni sp. nov., and D. stawiarskyi ); by the fingers not fringed nor webbed, D. imitator is distinguished from D. davori sp. nov. and D. brevipollicatus (fingers slightly fringed and webbed only at base), D. izecksohni sp. nov. and D. jureia sp. nov. (fingers fringed and webbed about one third), and D. krausae (fingers not fringed and webbed only at base).

Original description of type series ( Atelopus imitator Miranda-Ribeiro 1920 , freely translated from Portuguese)

Elongated, with the humerus shorter than the transverse diameter of the neck. Snout compressed and depressed, with lateral nostrils near the tip of snout, canthus rostralis evident, giving to loreal region a concave shape and continuing by the upper eyelid. Leg carried forward, the tarsal articulation almost reaching the posterior angle of the eye. Fingers as in A. cruciger ; toes same, that is, connecting through a rudimentary membrane, between the first extension is in the order: 1, 2, 4 and 3, and between second 1, 2, 3, 5 and 4. Body more granular in larger individuals, smoother in the shorter. Color pale cinereous or yellowish. A wide transverse stripe between the eyes; and from the vertex of the triangle that is posterior leave two divergent arms backwards, one or two further back, a dark stripe, on the flanks, starting from the snout and finishing in the iliac articulation, bordered of white on its sides; members with transversal stripes. Sometimes a narrow vertebral line, white. Abdominal side dark marbled. Body 23 mm, leg 28 mm.

Description of topotype. MZUSP 103992, adult male collected in Paranapiacaba, State of São Paulo, on March 24, 1963 by W.C.A. Bokermann and A.B. Costa.

Body slender, elongated ( Fig. 4 ); head triangular, longer than large, head length 36.4% of SVL; snout mucronate in dorsal view, acute in lateral view ( Fig. 5 ); snout 46.7% of head length; presence of a small tubercle under the tip of snout, nostrils not protuberant, small and elliptical, located laterally near the tip of snout, below the canthus rostralis; internarial distance 48.2% of eye to snout distance; eye diameter 58.6% of eye to snout distance and 77.2% of interorbital distance; eye protuberant; canthus rostralis slightly curved; loreal region vertical; vocal sac indistinct; choanae small, circular, very far from each other; tongue long, narrow, and few enlarged posteriorly; vocal slits present. Arms robust, forearms more robust than upper arms; hand with fingers slender, not fringed nor webbed; distal end of the third and fourth fingers slightly expanded laterally; finger I enlarged, covered by moderate nuptial pad with minuscule horny unpigmented asperities; relative lengths of fingers I< II < IV < III; subarticular tubercles single, rounded; outer metacarpal tubercle large, rounded; inner metacarpal tubercle rounded, slightly small than subarticular tubercles; supernumerary tubercles present, small; skinfold poor developed on the articulation of the first and second phalanges of the fingers II, III, and IV. Thigh length slightly shorter than tibia length; sum of thigh and tibia lengths about 93.5% of snout–vent length. Tarsal length about 23% of the snout–vent length. Foot with toes slender, not fringed; webbing formulae: I1–2 + II 11/2 –3 III2–3 IV 31/2 – 21/2 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 with the same size of subarticular tubercles, rounded; inner metatarsal tubercle large, approximately twice the outer, elongated; supernumerary tubercles present but scarce. Dorsal and lateral surfaces covered by spinulose granules uniformly distributed, with different sizes, ventral surfaces covered by numerous rounded granules; surfaces of upper eyelid with few granules sparse and external margin prominent; presence of two pronounced granules posterior to the corner of mouth.

Color in preservative. The topotypes present dorsum pale brown; a head blotch extending on the upper eyelids merging with an ‘X’ shaped blotch on the scapular region and an inverse ‘Y’ shaped blotch on the sacral region, extending to the inguinal region; one transversal bar on forearms and one blotch on elbow; one transversal bar on thigh, tibia, and tarsus, and one blotch on knee and heel; a lateral stripe starting at the snout, passing on the eye and reaching the inguinal region, being narrower in the loreal region; all of the bars, blotches, and stripes are dark brown; ventral surface lighter than the dorsum, with disperse small blotches.

Measurements of topotype. SVL 17.0; HL 6.2; HW 4.8; IND 1.4; ESD 2.9; ED 1.7; IOD 2.2; THL 7.7; TL 8.2; TAL 3.9; FL 6.8.

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. Sexual dimorphism can be observed on SVL (larger in female), on arms (slightly more robust in male), finger I (robust in male), and nuptial pad (on finger I of male). Nuptial pad can be pigmented or not.

Distribution. Dendrophryniscus imitator is known from the following municipalities ( Fig. 17 ) in the State of São Paulo, Brazil: Cubatão (23 o 51’S, 46 o 27’W, Datum WGS 84), Juquitiba (23 o 55’S, 47 oo 3’W, Datum WGS 84), Itanhaém, Parque Estadual da Serra do Mar Núcleo Curucutu (23 o 59’S, 46 o 44’W, Datum WGS 84), Natividade da Serra (23 o 22’S, 45 o 26’W, Datum WGS 84), Salesópolis (23 o 38’S, 45 o 52’W, Datum WGS 84, 900 m altitude), Santo André, Paranapiacaba (23 o 46’S, 46 o 17’W, Datum WGS 84), Santos (23 o 56’S, 46 o 19’W, Datum WGS 84), São Bernardo do Campo (23º45’S, 46º33’W, Datum WGS 84), São Paulo, Represa Billings (23 o 48’S, 46 o 37’W, Datum WGS 84), Cotia, Reserva do Morro Grande (23 o 43’S, 46 o 57’W, Datum WGS 84).

Natural history. This species is associated to forested areas, from 100 m to 1100 m above sea level, and breeds in bromeliads, where its larvae develop ( Malagoli et al. 2017, as D. brevipollicatus ).

Remarks. All individuals of the type series have tip of snout kneaded. All skin is unpigmented and surface granulation and crenulations are few evident because time of preservation. For this reason, we presented the original description and made a new description based on a topotype from Paranapiacaba, State of São Paulo. In the original description the author refers to five specimens composing the type series: two from Santos, Cubatão, São Paulo ( MZUSP 477–485) collected by Bicego on December 1897; one from Alto da Serra ( MZUSP 847), collected by Bicego in 1899; one from Rio Grande, State of São Paulo ( MZUSP 835), collected by Wacket on July 1902; and one from Campo Grande, State of São Paulo ( MZUSP 639), collected by Wacket on May 1902. The specimen MZUSP 835 from Rio Grande was lost and the tag number of the specimen from Campo Grande is MZUSP 634. We concluded that body measures presented by Miranda-Ribeiro in the original description were based on specimen MZUSP 847 from Alto da Serra (now, Paranapiacaba).

The specimens referred by Heyer et al. (1990) and Malagoli et al. (2017) as Dendrophryniscus brevipollicatus are now D. imitator .

Figures

FIGURE 3. Dendrophryniscus imitator (Miranda-Ribeiro, 1920), lectotype, MZUSP 847 (SVL 21.5 mm). Dorsal and ventral views.

FIGURE 4. Dendrophryniscus imitator (Miranda-Ribeiro, 1920), topotype, MZUSP 103992 (SVL 17.0 mm). Dorsal and ventral views.

FIGURE 5. Dendrophryniscus imitator (Miranda-Ribeiro, 1920), topotype, MZUSP 103992 (SVL 17.0 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.