Eleutherodactylus nebulosus Henle, 1992

Koehler, Joern, Castillo-Urbina, Ernesto, Aguilar-Puntriano, Cesar, Vences, Miguel & Glaw, Frank, 2022, Rediscovery, redescription and identity of Pristimantis nebulosus (Henle, 1992), and description of a new terrestrial-breeding frog from montane rainforests of central Peru (Anura, Strabomantidae), Zoosystematics and Evolution 98 (2), pp. 213-232 : 213

Eleutherodactylus nebulosus Henle, 1992

Redescription of the holotype.

An adult male (Fig. 1 ) with subgular vocal sac and vocal slits. SVL 28.6 mm (for additional measurements see Table 1 ). Head slightly longer than wide (HL/HW = 1.1); snout shape NA; nostrils oriented posterolaterally; canthus rostralis straight in dorsal view, sharp in profile; loreal region very slightly concave; lips not flared; upper eyelid without tubercles; cranial crests absent. Supratympanic fold prominent, long, curved, surrounding the upper tympanic membrane; tympanic membrane and annulus distinct; tympanic membrane nearly round on the left side, slightly higher than long on right side, its length less than half the eye diameter; two prominent postrictal tubercles, conical. Choanae not concealed by palatal shelf of the maxillary arch when roof of mouth is viewed from below; choanae large, ovate, separated by distance equal to six times diameter of a choana; dentigerous process of vomers prominent, triangular in shape, not in contact, oblique, situated posteromedial to choanae; vocal sac subgular, vocal slits placed posterolaterally. Skin of dorsal surfaces shagreen, with few scattered low tubercles; skin on throat, chest and belly weakly areolate, almost smooth; occipital folds absent; dorsolateral folds present, low, formed by a discontinuous row of anastomosed granules; discoidal fold conspicuous. Arm without ulnar tubercles; palmar tubercle bifid, relatively flat, equal to elongate thenar tubercle; few supernumerary tubercles present, low, round, smaller than subarticular tubercles; subarticular tubercles prominent, subconical; finger tips enlarged (NA completely due to desiccation and shrinking); fingers without lateral fringes; basal webbing between fingers II and III; relative length of fingers III> IV> II ≤ I; traces of a single non-spinous nuptial pad on dorsal surface thumb. Toes long and slender (FootL 55% of SVL); heel and tarsus lacking tubercles; tarsal fold NA; inner metatarsal tubercle ovate, flat, larger than outer; outer metatarsal tubercle round, flat; supernumerary tubercles NA; subarticular tubercles present (but strongly desiccated); lateral fringes on toes NA, basal toe webbing present; toe tips NA (but T-shaped phalanges visible, indicating expanded toe tips); ungual flap and circumferential grooves NA; relative length of toes IV> V> III> II> I; toe V reaching proximal level of penultimate subarticular tubercle of toe IV. Tibiotarsal articulation reaches far beyond tip of snout when hind limb flexed parallel to axis of body; heels broadly overlapping when hind limbs flexed perpendicular to axis of body.

After 42 years in preservative (Fig. 1 ), the dorsal surfaces are overall tan to brown of different shades, with dark brown chevrons outlined with cream; arms and legs are barred with brown bars the same colour as those of dorsum and the same colour applies to vertical bars on the flanks, which are also outlined with cream; dark brown interorbital bar; canthus rostralis darker than surrounding skin; triangular cream coloured fleck on tip of snout; supratympanic fold and a pair of occipital spots black; posterior surfaces of thighs brown, with fine scattered irregular cream spots; chest and belly greyish-white with some scattered irregular brown flecking on chest; throat cream-coloured, but densely mottled with fine brown to grey spots and flecking which (like those on chest) are rather distinct and contrasted; lower and upper lips brown and barred with cream; soles of hands and feet brown with irregular cream flecking.

Our examination of the type specimen revealed the following discrepancies to the original description: Henle (1992) described the first finger being longer than the second. Although this appears to be correct at first view (see Fig. 1 ), it is to be mentioned that the tip of finger II is almost completely desiccated and thus the finger apparently lost some of its total length. However, even at this state of preservation, when fingers I and II are adpressed against each other, they are about equal in length. At most, we could state that finger I is only slightly longer than finger II. Henle (1992) described the terminal finger discs as being only slightly expanded. As stated above, distal fingers of the holotype are completely desiccated and apparently were already during the time of the species description ( Henle 1992: fig. 2). As a consequence, finger discs are barely obvious, but when viewed with magnification, T-shaped terminal phalanges are clearly visible, indicating the probable former presence of expanded finger discs. The original description ( Henle 1992) stated that an outer metatarsal tubercle is lacking. The desiccation event apparently resulted in less distinct and less elevated tubercles on hands and feet (including subarticular tubercles) in the holotype, but with strong magnification (> 20 ×), skin structures become evident which likely once represented a flat outer metatarsal tubercle. Moreover, Henle (1992) described the tympanum as being slightly higher than long, a state we were able to confirm only for the right body side of the holotype, whereas it exhibits a nearly round tympanum on the left body side (Fig. 1 ). We reject Henle’s (1992) statement that toes exhibit webbing of about one fourth of their length, as only basal webbing is present between the toes of the holotype. The supratympanic fold has been described as weakly developed by Henle (1992), but it is actually rather distinct in the holotype. Due to the condition of the type specimen, we were unable to confirm or reject Henle’s (1992) characterisation of the snout shape. As mentioned above, fleshy parts are almost completely lacking at the anterior head of the holotype and the shape of the head in its current condition seems to be basically represented by the skull shape. Moreover, the head shape has likely been altered by its dorsoventral compression and squeezing.

Figures

Figure 1. Preserved holotype of Eleutherodactylus nebulosus Henle, 1992 (ZFMK 27634) in a. dorsal and b. ventral views; c. Palmar surface of left hand; d. Head in lateral profile. Note that due to the poor state of preservation and damage, certain characters appear to be altered, including body shape, finger length, finger discs, and head shape.