A new species of dink frog, genus Diasporus (Anura: Eleutherodactylidae), from the Caribbean foothills of the Cordillera de Talamanca, Costa Rica Author Arias, Erick Author Chaves, Gerardo Author Salazar, Stanley Author Salazar-Zúñiga, José Andrés Author García-Rodríguez, Adrián text Zootaxa 2019 2019-05-23 4609 2 269 288 journal article 26711 10.11646/zootaxa.4609.2.4 e92bcf89-527e-4af1-910c-33308a67da07 1175-5326 3187611 94C0C804-603D-4C62-A841-D22BB040BB66 Diasporus amirae sp. nov. Amira’s dink frog ( Figures 5–6 ) urn:lsid:zooBAnk.org:Act: 4C5AE14B-3B6C-4846-946C-CC6BB15FF42 Holotype . UCR 21843, an adult male from Costa Rica : Provincia de Limón : Cantón de Limón : Distrito de Matama : Cerro Plátano (9.870º, -83.240º; 1000 m a.s.l. ) in the northeastern of the Cordillera de Talamanca ; collected by Gerardo Chaves , Adrián García-Rodríguez , Stanley Salazar , and Gilbert Alvarado on 8 March 2013 . Paratypes . UCR 21842, adult male, same data as the holotype . UCR 22010–2, adult males, from of Plátano peak, near of type locality (9.869º, -83.241º; 1121 m a.s.l.), collected by Gerardo Chaves, José Andrés Salazar- Zúñiga, Julissa Gutiérrez, Diego Salas, and Ruperto Madrigal on 6 September 2013 . UCR 22554, adult male from Plátano peak, near of type locality (9.863º, -83.236º; 1000 m a.s.l.), collected by Gerardo Chaves, José Andrés Salazar-Zúñiga, and Juan Ignacio Abarca on 18 June 2015 . Generic placement. This small species is assigned to the genus Diasporus based on its phylogenetic position, its characteristic “dink” call and the presence of palmate disc covers on some fingers and toes. Diagnosis. A small species of the genus Diasporus with the following characteristics: (1) skin on dorsum smooth to having scattered tubercles; head having scattered tubercles; venter smooth in the midline but weakly areolate in the transition to flanks; flanks weakly areolate to granular; posterior surface of hind limbs surrounding cloaca strongly areolate; without dorsolateral, lateral, discoidal or supratympanic folds ( Fig. 5 ); (2) tympanic membrane round, small, and indistinct; annulus partially evident through the skin; (TY/ED = 18.5–41.9 %); (3) snout subovoid in dorsal view, rounded in profile; loreal region concave; canthus rostralis usually rounded ( Fig. 6 ); (4) eyelid areolate (EW/IOD = 57.7–65.2 %); cranial crests absent (5) vomerine teeth on oblique odontophores, barely distinct; (6) vocal slits large in adult males; single external subgular vocal sac present; nuptial pads absent; (7) Finger II larger than Finger I; discs and terminal transverse grooves present on all the fingers; tips symmetric, disc covers palmate on Finger III, sometimes also on fingers II and IV, others fingers with disc covers rounded; pads usually broadened, sometimes triangular on Finger III ( Fig. 6c ); (8) fingers lack lateral fringes; webbing absent; thenar tubercle elongate, palmar rounded, thenar and palmar tubercles flattened and similar in size; supernumerary and accessory palmar tubercles absent; subarticular tubercles round in basal outline, flatted in form and globular in profile; (9) ulnar tubercle and fold absent; (10) heel smooth; inner tarsal folds absent; (11) toes lack lateral fringes; inner metatarsal tubercle elongate, outer rounded, much smaller than inner, inner and outer metatarsal tubercles projecting; supernumerary tubercles and plantar absent; subarticular tubercles ovoid in basal outline, flatted in form and globular in profile; (12) Toe V larger than Toe III; discs and terminal transverse grooves present on all the toes; tips symmetrical, disc covers palmate on Toe IV, sometimes also on toes III and V, others toes with disc covers rounded; pads broadened; webbing absent; (13) dorsum brown with a black spots or brown-grayish with several black spots, almost uniform; venter pale gray-bluish with pale blotches forming a pattern of pale gray blotches; throat uniform dark gray-bluish; forelimbs and hind limbs with dark bars; some specimens with a dark supratympanic stripe; mask, occipital, labial, or lateral marks absent; (14) SVL in males 18.0–23.0 mm. Comparisons with other species. Diasporus amirae differs from other species of Diasporus in the following characters (condition for D. amirae in parentheses). Diasporus anthrax ( Lynch, 2001 ) differs from D. amirae by having red blotches on the surfaces of limbs (limbs brown-grayish to gray-blackish with black stripes). Diasporus citrinobapheus Hertz et al ., 2012 has a yellow to bright orange dorsum and translucent venter with white mottling (dorsum brown to brown-grayish and venter gray-bluish with pale blotches). Diasporus darienensis Batista et al ., 2016 usually has a slightly enlarged conical supraocular tubercle (eyelid areolate but never with a conical supraocular tubercle), a brown to reddish dorsum, usually with a pair of red or pale dorsolateral lines (dorsum brown to brown-grayish uniform never with dorsolateral lines). Diasporus diastema ( Cope, 1875 ) has a pale gray to tan dorsum and yellow venter and groin, usually with a pair of light dorsolateral stripes extends from the shoulders to the pelvis (dorsum brown to brown-grayish and venter and groin gray-bluish with pale blotches, without a pair of dorsolateral stripes). Diasporus gularis ( Boulenger, 1898 ) has a pale brown dorsum, cream venter, and a yellow groin, and usually shows a significant amount of red in its color pattern (dorsum brown to brown-grayish and venter and groin gray-bluish with pale blotches, without red in its color pattern), usually with a dark bar between the eyes (without a dark bar between the eyes). Diasporus hylaeformis ( Cope, 1875 ) has a pale yellow to orange venter and groin (venter and groin gray-bluish with pale blotches). Diasporus igneus Batista at al., 2012 shows rounded scattered tubercles in the dorsum (dorsum smooth to scattered tubercles), an enlarged and conical supraocular tubercle (eyelid areolate but never with a conical supraocular tubercle), yellow to orange reticulations in the dorsum and a yellow venter (dorsal coloration brown to brown-grayish without light reticulations, venter nearly uniform, gray with dark brown pigment). Diasporus majeensis Batista et al., 2016 has smooth dorsal skin with small-dispersed tubercles (dorsum smooth to areolate), dorsum brown to reddish and venter translucent (dorsum brown to brown-grayish and venter gray-bluish with pale blotches). Diasporus pequeno Batista et al., 2016 has a rounded supraocular tubercle (eyelid areolate but never with a conical supraocular tubercle), ungual flap lanceolate to papillate (ungual flap palmate to rounded), dorsum brown to cream, with dark reticulations, venter translucent (dorsum brown to brown-grayish and venter and groin gray-bluish with pale blotches). Diasporus quidditus ( Lynch, 2001 ) and D. tinker ( Lynch, 2001 ) have the ungual flap lanceolate to papillate on fingers II-III (ungual flap palmate to rounded), dorsum gray to brown and venter brown to orange (dorsum brown to brown-grayish and venter and groin gray-bluish with pale blotches). Diasporus sapo Batista et al ., 2016 has snout rounded in dorsal view (snout subovoid in dorsal view), dorsal skin slightly tuberculate (dorsum smooth to scattered tubercles), dorsum reddish and venter translucent (dorsum brown to brown-grayish and venter gray-bluish with pale blotches). Diasporus tigrillo ( Savage, 1997 ) has dorsum with low pustules and yellow to bright orange in coloration (dorsum smooth to scattered tubercles and brown to brown-grayish in coloration), venter white (venter gray-bluish with pale blotches). Diasporus ventrimaculatus Chaves et al ., 2009 has venter typically blotched and contrasting or with light to red coloration (venter gray-bluish with pale blotches, without contrasting blotches). Diasporus vocator ( Taylor, 1955 ) differs from D. amirae by: a) having a dark interorbital bar with a paler area anterior to it ( Fig. 7a , [without interorbital bar]), b) its smooth head (head scattered tubercles), c) its snout pointed (snout rounded); d) its disc covers in fingers and toes oblong ending with a distinct point (disc covers in fingers and toes palmate or rounded), and e) smaller, SVL in adults 14–18 mm (larger, SVL in adults 18.1–21.8 mm ). Diasporus sp. A has a pale interorbital bar ( Fig. 7d , [without interorbital bar]), and its smooth head (head scattered tubercles). Description of holotype . Adult male having a SVL of 18.5 mm ( Fig. 6 ). Head narrow, HW 37.8 % of SVL; HL 33.5 % SVL; snout subovoid in dorsal view, rounded in profile; canthus-rostralis indistinct; loreal region slightly concave; nostrils small, directed laterally; vocal slits large, single external subgular vocal sac present; vomerine teeth barely discernable, positioned transversely in two fascicles well posterior of choanae. Eye large, diameter equal to two and half of E-N. Tympanic membrane indistinct, covered in skin; tympanic annulus weak to partially discernable below skin, small (33.3 % of ED), round. Skin on dorsum smooth, venter smooth in the midline but becomes weakly areolate towards flanks, throat and head smooth, flanks weakly areolate; without dorsolateral, lateral, discoidal, supratympanic or interocular folds; eyelid smooth; inguinal gland and postrictal tubercles absent. FIGURE 5. Color in life view of Diasporus amirae sp. nov. A ) Dorsum and B ) venter in nighttime coloration, and C ) dorsum in daytime coloration. Photos A–B by S. Salazar and C by J. A. Salazar-Zúñiga. Forelimbs relatively short and slim. Fingers moderately long and robust, proximal section slightly wider than distal section; without lateral fringes; Finger II larger than Finger I. Discs and terminal transverse grooves on all the fingers; tips symmetric, disc covers on Finger I and IV round, palmate on fingers II and III; disc pads broadened. Thenar tubercle elongate, palmar rounded, thenar and palmar flattened and similar in size. Supernumerary and accessory palmar tubercles absent; subarticular tubercles on fingers barely discernable, rounded basally, flattened in form and globular in profile. Ulnar tubercles and fold absent. Fingers lack interdigital webbing. Hind limbs relatively short and slim. Toes without lateral fringes; Toe III shorter than Toe V. Discs and terminal transverse grooves on all the toes; tips symmetrical; disc covers rounded on toes I, II, and V, palmate on toes III and IV; disc pads broadened. Inner metatarsal tubercle elongated; outer metatarsal tubercle rounded, much smaller than inner, both inner and outer metatarsal tubercles projecting. Supernumerary and plantar tubercles absent; subarticular tubercles on toes ovoid basally, flattened in form and globular in profile. Heel smooth, inner tarsal fold absent. Toes lack interdigital webbing. Coloration in life. Diasporus amirae is metachromatic and shows a high-level of color variation between day and night. While active at night the dorsum was observed to be dark brown with black marks ( Fig. 5 a-b), but while inactive, in the daytime, the dorsum was observed to change to a bronze coloration with bluish black marks that form thin lines across the girdles and in the interorbital area ( Fig. 5c ). We consider that the dark brown coloration of the dorsum is more characteristic of this species because the dorsal background of the preserved specimen in ethanol is gray ( Fig. 6 ). The venter is usually gray-bluish with pale blotches. The dorsal surfaces of the forelimbs and hind limbs are similar to the dorsum, and present black-bluish marks. The flanks and groins are similar in coloration to that of the venter. The iris is brown. Coloration of the holotype in ethanol. After five years in ethanol (70 %), the dorsum and head is gray-blackish with several black blotches; a narrow pale interorbital band present; a dark supratympanic stripe extending from the orbit to the suprascapular shoulder; venter gray with dark brown pigment, forming a pattern of pale blotches on dark background due to the lack of dark brown pigment; throat black, vocal sac uniformly gray-blackish; flanks and groin similar to dorsal background; dorsal surface of forelimbs and hind limbs similar to dorsal background with darker marks; ventral surfaces of forelimbs and hind limbs dark brown with pale blotches; ventral surfaces of hands and feet dark brown, with pale blotches on fingers and toes; posterior and anterior surfaces of hind limbs uniform dark brown ( Fig. 6 ). FIGURE 6. A ) Dorsum, B ) venter, C ) right hand, and D ) right foot of the holotype (UCR 21843) of Diasporus amirae sp. nov. Photos by E. Arias. Measurements of holotype (mm). SVL 18.5; HL 6.2; HW 7.0; ED 3.0; IOD 2.8; TY 1.0; EW 1.5; E–N 1.2; F1 2.0; F2 2.2; F3 3.6; F4 3.0; T1 2.9; T2 3.5; T3 5.0; T4 7.1; T5 5.1; TL 9.5. Morphometric and morphological variation of paratypes . We did not find evident morphological variation among the five paratypes , and little variation was observed in their coloration. Dorsal background in UCR 22010, 22012, and 22554 is nearly uniform black (in ethanol). The dorsal background coloration of UCR 22011 is paler than the holotype . The ventral surfaces of UCR 22010 are paler than the holotype , with little dark brown pigment. Natural history notes. We have found only two populations of Diasporus amirae , both above 1000 m a.s.l., on the Plátano peak and a nearby unnamed peak. Both peaks are covered by primary forest, and are categorized as Tropical Wet Forest ( Holdridge 1967 ), lacking a dry season, having an annual precipitation range between 3000 to 4000 mm , and annual temperatures oscillating between 18 to 28 ºC. On Plátano peak D. amirae was detected only along the northern slope, in the last 200 m of the ascent to Plátano’s summit. The new species has been observed calling during the night from low vegetation (less than 1 meter above the ground) or within the leaf litter near the walls of small stream canyons. However, we also detected some males calling from trees, up to 6 meters high. This species appears to be very shy; when disturbed, males stop calling for several minutes, such behavior is rare in other species of Diasporus in which males keep quiet when disturbed, but start over their calling activity almost immediately. In relation to the calling activity, D. amirae behaves similar to many other anuran species that call during the night but also can vocalize during the afternoon on rainy days ( Savage 2002 ). According to the call activity during the sampled months, D. amirae seems to be less common than the sympatric D. aff. diastema in the area. We did not find females, juveniles or eggs in spite of 158 man-hours of searching effort during a total of eight nights of fieldwork in three different months. Vocalizations. The advertisement call of Diasporus amirae consists of a single modulated note ( Fig. 4 ) with a mean duration of 0.256 ± 0.015 s . Dominant frequency in this species ranges in mean from 2.871 ± 0.039 kHz at the beginning of the call to 3.273 ± 0.051 kHz at the end of the call. Compared to other modulating species in the genus, the duration of the call of D. amirae is more than six times the duration of the call of D. vocator ( Table 2 ) and twice the duration of the calls of D. tigrillo and D. citrinobapheus ( García-Rodríguez et al. 2016 ) . This is the most evident difference to the human ear, due to the fact that the narrow frequency range and the long duration results in a lower slope in dominant frequency making modulation less perceptible ( Table 2 ). In contrast, other species such as D. vocator or D. tigrillo use wider frequency ranges in shorter calls, giving their vocalization a whistle-like tone. Geographic distribution. Diasporus amirae is currently known to be restricted to the headwaters of the Río Banano on the northeastern foothills of Cordillera de Talamanca, Caribbean slope, Costa Rica ( Fig. 1 ). The known altitudinal range of the new species is 1000–1121 m a.s.l. The known populations of D. amirae are within La Amistad International Park. We believe that more fieldwork is needed to better understand the potential distributional range of this species. Diasporus amirae is sympatric with D. aff. diastema . Etymology. The name amirae is a matronym dedicated to Stanley Salazar’s daughter, Amira Salazar who was born in May 2017 .