Aromobates zippeli, Barrio-Amorós, César Luis & Santos, Juan Carlos, 2012

Barrio-Amorós, César Luis & Santos, Juan Carlos, 2012, A phylogeny for Aromobates (Anura: Dendrobatidae) with description of three new species from the Andes of Venezuela, taxonomic comments on Aromobates saltuensis, A. inflexus, and notes on the conservation status of the genus, Zootaxa 3422, pp. 1-31 : 16-20

Aromobates zippeli sp. nov.

Holotype. CVULA 8329, an adult male from the immediate surroundings of Mucuchíes, Estado Mérida, Venezuela, 8.75 N, 70.8833 W, elevation 2970 m, collected by Willians Abreu on December 28th, 2004.

Paratopotypes. Four adult males, CVULA 8331-33, 8336, and seven adult females, CVULA 8330, 8334-35, 8337-40, all with the same data as the holotype. One subadult female, CVULA 8341, and a juvenile, CVULA 8342, collected by W. Abreu on April 28th, 2010, at the type locality.

Tadpoles. Unknown.

Definition: We assigned this species to Aromobates based on the following characters. (1) Skin on dorsum smooth to shagreen. (2) Paired dorsal scutes present on digits. (3) Distal tubercle on FIV present. (4) FIV length surpasses half distal subarticular tubercle of FIII. (5) FI slightly longer than II. (6) Digital discs present. (7) Finger discs barely expanded. (8) Finger fringes present. (9) Metacarpal ridge absent. (10) FIII not swollen in adult males. (11) Carpal pad absent. (12) Male excrescences on thumb absent. (13) Thenar tubercle present, small. (14) Black arm gland in adult males absent. (15) Tarsal keel indistinct. (16) Toe discs weakly expanded. (17) Toe webbing formula II1 ½- 3III 2½- 3IV. (18) Metatarsal fold absent. (19) External coloration with pale dorsolateral stripes; ventrolateral stripe absent; oblique lateral stripe formed by a series of diffuse bluish white spots. (20) Gular-chest markings absent, evenly stippled. (21) Dermal collar absent. (22) Male throat coloration dirty white to grey with profusion of melanophores, evenly stippled; female throat coloration white with scattered melanophores. (23) Male abdomen color white with scattered melanophores and indistinct bluish white small spots. (24) Female abdomen color pattern white with few scattered melanophores. (25) Iris coloration bronze with fine black reticulation, pale golden pupil ring. (26) Large intestine unpigmented. (27) White testes. (28) Median lingual process absent. (29) Tympanum indistinct, tympanic annulus absent. (30) Vocal sac distinct. (31) Teeth present on the maxillary arch. (32) Body size small, males (n = 5) 19.0– 21.5 mm, mean = 20.6 ± 1.0; females (n = 7) 20.0–25.0 mm, mean = 23.5 ± 1.6.

Comparisons. Aromobates zippeli (characters in parenthesis) differs by its smaller size from large species of the genus, such as A. alboguttatus , A. leopardalis , A. meridensis , A. nocturnus , and A. capurinensis , all with maximum SVL> 31 mm (up to 25.5 mm). However, it is worthy to compare A. zippeli with A. alboguttatus and A. leopardalis , both larger species but very close geographically; A. zippeli could occur sympatrically with A. leopardalis . Aromobates alboguttatus is a larger species, up to 31.5 mm (females up to 25 mm), with a low but distinct tarsal keel (indistinct to absent), fringes on fingers evident (absent to low), basal webbing (I-II1½- 3III 2½-3IV-V), and this species has reticulated throat (evenly stippled). Aromobates leopardalis is much larger, females reaching 35.3 mm (25 mm), with no dorsolateral stripes, and not defined oblique lateral stripe (both present and distinct), extensive flap-like fringes on toes (present but not extensive), and FI shorter than FII (FI longer than FII). Nine other species of Aromobates ( A. cannatellai sp. nov., A. duranti , A. ericksonae sp. nov., A. haydeeae , A. mayorgai , A. molinarii , A. orostoma , A. saltuensis , and A. serranus ) are similar in size to Aromobates zippeli . Aromobates cannatellai is somewhat larger, with females up to 28.6 mm (25.0), finger discs moderately expanded (barely expanded), toe discs moderately expanded (weakly expanded), this species has a distinct tarsal keel (indistinct to absent) and dorsal surfaces lack small white spots (present). Aromobates duranti is a little larger frog, up to 30.7 mm (up to 25.0 mm), this species has its venter grey with conspicuous white dots (grey to white), tarsal keel short but distinct (indistinct to absent). Aromobates ericksonae has a thick tarsal keel (indistinct to absent), toe webbing basal (moderately webbed I-II1½- 3III 2½-3IV-V), and this species surfaces are never covered by small white spots (present). Aromobates haydeeae has no fringes on fingers (present), dorsal color reddish copper without white spots (dark to light brown with white spots), and ventral parts orange (dirty yellow). Aromobates mayorgai has dorsal skin smooth with a few tubercles posteriorly (smooth to shagreen without tubercles), FI shorter than FII or equal (FI longer than FII), oblique lateral stripe absent (formed by small whitish spots), and tarsal keel prominent (indistinct to absent). Aromobates molinarii is a larger frog, females up to 30.3 mm (up to 25.0 mm), it has FI and II equal in length (FI longer than FII), fringes absent on fingers (present), disc on FIII twice as wide as the adjacent phalanx (1.3 wider), and oblique lateral stripe absent (formed by small whitish spots). Aromobates orostoma has a distinct tympanum (indistinct), FI shorter than FII (FI longer than FII), and no fringes on fingers (present). Aromobates saltuensis has no fringes on fingers (evident), tarsal keel well-defined (indistinct to absent), and a short anal sheath (absent). Aromobates serranus has a distinct tympanum (indistinct), FI shorter than FII (FI longer than FII), tarsal keel present (indistinct to absent), dorsum reticulated (spotted but not reticulated), and belly parts creamy white with brown reticulation (yellow to white, no reticulation).

Description of the holotype. The holotype is an adult male of 22.0 mm (SVL): body robust, rounded in crosssection; dorsal skin, including dorsal surfaces of hind limbs, shagreen in preservative; throat and chest skin smooth, belly, finely granular; head as long as wide, HeL = 34.5% of SVL; HW = 34.5% SVL; snout is rounded in profile, rounded in dorsal and ventral view; nares are situated laterally to the tip of snout; narial openings are barely visible when viewing the head from the front, not visible when viewing dorsally; and barely seen when viewing from a ventral aspect; canthus rostralis is straight, rounded; the loreal region is flat; interorbital region is little narrower than the upper eyelid; snout is longer than ED; tympanum is indistinct, only barely visible on its anteroventral portion; supratympanic bulge is indistinct; tympanum is positioned closely behind eye and lower, close to the angle of jaws; teeth are present on maxillary arch; vocal slits are large, arched from mid-level of tongue to anterior to the angles of jaws; tongue is large, rounded, and one-third free posteriorly.

Hand of moderate size (25% SVL); relative lengths of adpressed fingers are III> I> II> IV; discs of all fingers are slightly expanded, horizontally oval; FIII is barely wider than distal end of adjacent phalanx; the base of palm has a large, rounded palmar tubercle; and on base of FI there is an indistinct, smaller (approximately 1/3 of the palmar tubercle), oval thenar tubercle; one or two subarticular tubercles on fingers (one each on FI and FII, two each on FIII and FIV, the distal one of FIV inconspicuous); and all tubercles are flat and round or oval; without supernumerary tubercles. Fringes are present on all fingers and quite distinct.

Hind limbs quite short, SL = 45% SVL; relative lengths of adpressed toes are IV> III> V> II> I; TI is moderately long, the tip reaching the mid-subarticular tubercle of TII; toe discs are barely expanded, TIV about 1.2 times wider than distal end of adjacent phalanx; feet are basally webbed, formula is I-II1½- 3III 2½-3IV-V; fringes on toes are present and low; one to three non-protuberant small subarticular tubercles are present (one on TI and TII, two on TIII and TV, three on TIV, proximal one almost indistinct); two metatarsal tubercles are present, including a small round outer, and a similar in size elongated inner tarsal tubercle; tarsal keel is indistinct; cloacal opening is located at the upper level of thighs; and the anal sheath is absent.

Measurements of holotype (in mm). SVL: 22.0; SL: 9.9; FL: 8.8; HeL: 7.6; HW: 7.6; ETS: 3.2; EN: 1.8; ED: 2.6; TD: 1.2; HD: 5.5; 1FiL: 3.9; 2FiL: 3.8.

Color of the series. After preservation, Aromobates zippeli specimens have their dorsum very dark brown, with a little evident vertebral stripe made by small pale white spots, starting from the tip of snout to the sacrum. The two dorsolateral stripes are pale blue in life (appearing white in preservative) with small spots. Specimen flanks are black with an irregular oblique lateral stripe also made by small dirty white spots; some white spots are on the lowest part of the flanks, close to the paler ventral area. Arms are dark brown with fine irregular pale brown spotting. Hind limbs are dark brown without definite crossbars; thighs are paler than shanks, all with irregular pale brown spotting. Ventrally, throat and chest grey are evenly spotted with a profusion of melanophores (only seen under magnification); belly is dirty white, with scattered melanophores, and a few indistinct (only possible to distinguish under microscope) bluish white spots. Palms and soles are dark brown.

Coloration in life specimens (based on living, not collected specimens and CVULA 8341) is as follows. The dorsum can be olive ( Fig. 9 A), light to dark brown or even black, with an irregular pattern. Alternatively, the dorsum can have irregular spotting of dark brown over a light brown background or it can be brown over black ( Fig. 9 B). Flanks are dark brown to black, always darker than the dorsum. The two light dorsolateral stripes can be pale yellow, golden, or olive; but are always paler than the dorsum and flanks. The ventrolateral stripe is absent. The oblique lateral stripe can be short, just in the inguinal area, or long, extending above the upper arms. This stripe is always formed by small bright white spots, than can be pale blue at midbody or above the upper arms. Arms and hind limbs have also a pale background with irregular dark spotting or crossbars. The most striking chromatic character of Aromobates zippeli is that any part of its dorsal body can be covered by small rounded bluish to white spots, especially in the flanks, dorsum (even over the dorsolateral stripes), upper lips and loreal region. Ventrally ( Fig. 9 B) a subadult female (CVULA 8341) was found to be patternless with a dirty yellow to dirty white background; a series of very diffuse small pale white spots were distinguished under magnification.

Variation. Dorsal skin can be smooth to shagreen without tubercles, both in living and preserved specimens. Fringes on fingers and toes are present on all specimens. Tarsal keel in this species is indistinct in almost all specimens, but it is completely absent in CVULA 8338 and 8340. Only CVULA 8335 and 8337 have what appears to be an anal sheath; this data agrees with Grant et al. (2006), which prevented that this characteristic can be variable. CVULA 8339 presented an extra toe on the left foot. The extra toe rises from the TIII towards its superior side, being of the same length and having a small disc and fringes. This case of complete polydactylia is the second reported in Venezuelan dendrobatids, after a case of partial polydactylia on Mannophryne riveroi ( Barrio-Amorós et al. 2010c). CVULA 8334 has the last section of FII and III missing, showing the phalanges exposed.

The color pattern variation was also present ( Fig. 9 C). One individual (CVULA 8340) has irregular dark blotches on dorsum; while the series CVULA 8337-38 are patternless dorsally and their dorsolateral stripes are thin but not made with spots. Crossbars are also variable from distinct (CVULA 8332, 8335) to indistinct or ill-defined. Ventrally, males are usually darker than females. Male CVULA 8333 is the darkest in coloration, CVULA 8331-32 are similar to the holotype, and CVULA 8336 is the ventrally paler in coloration. This last specimen appears to be white at first glance with some melanophores on the throat under magnification. Females of Aromobates zippeli have paler ventral surfaces, mostly whitish with few scattered melanophores on the throat.

Natural history. Aromobates zippeli is a subpáramo dweller, known only from the type locality at 2970 m and restricted to only one creek. The individuals of this species were found under rocks and between aquatic and terrestrial vegetation along the creek. Tadpoles are unknown.

Vocalization. Unknown.

Phylogenetic relationships. Unknown. However, Manzanilla et al. (2009) provided molecular data from individuals identified as Aromobates sp. (MIZA 310-312) collected along the road from Mérida city to Barinitas, near the locality of Mucuchíes, We did not review those specimens and, consequently, we cannot rule out that they may be conspecific with A. zippeli .

Distribution. Aromobates zippeli is known from a small area of probably less than 5 km 2 NE of the town of Mucuchíes. During our search, we were able to find individuals only in a single creek. This general area has been profusely searched for amphibians for many years (especially, by professors and students of the Universidad de los Andes) as supported by plenty of specimens collected and housed in the CVULA collections. Based on the current information, we regard this species as a restricted endemic taxa to Mucuchíes ( Fig. 3 ). Aromobates leopardalis is sympatric and it might be syntopic with A. zippeli . However, A. leopardalis is much larger and likely to be restricted to a more open páramo habitat.

Etymology. Zippeli is a patronym for Kevin C. Zippel, due to his passion and endless work in spreading the alarming message of the global decline of frogs, through the Amphibian Ark (Amphibian Ark: http://www.amphibianark.org/).

Figures

FIGURE 3. Collection localities including type localities of Aromobates (squares) along the Cordillera de Mérida, Serranía de Perijá, and northern Eastern Cordillera of Colombia. Several species might be sympatric and syntopic.

FIGURE 9. Aromobates zippeli sp. nov. (A) Lateral view of subadult paratopotype female CVULA 8341. (B) Ventral view of same specimen in A. (C) two uncollected specimens, showing variation in pattern. Photos by CBA.