Adenomera inopinata, Carvalho & Moraes & Lima & Fouquet & Peloso & Pavan & Drummond & Rodrigues & Giaretta & Gordo & Neckel-Oliveira & Haddad, 2021

Carvalho, Thiago R. D., Moraes, Leandro J. C. L., Lima, Albertina P., Fouquet, Antoine, Peloso, Pedro L. V., Pavan, Dante, Drummond, Leandro O., Rodrigues, Miguel T., Giaretta, Ariovaldo A., Gordo, Marcelo, Neckel-Oliveira, Selvino & Haddad, Célio F. B., 2021, Systematics and historical biogeography of Neotropical foam-nesting frogs of the Adenomera heyeri clade (Leptodactylidae), with the description of six new Amazonian species, Zoological Journal of the Linnean Society 191, pp. 395-433 : 420-422

ADENOMERA INOPINATA , SP. NOV.

UNFORESEEN TERRESTRIAL NEST- BUILDING FROG

( FIGS 2B, 3–4, 5H, 6H, 7H, 10A–B, 12A–B;

TABLES 1-3)

lsid urn:lsid:zoobank.org:act:E21553B7-A8CC-495A-8056-E8C203A7A9B6

Holotype: INPA-H 40517 (field # DT 3923 ), adult male, BRAZIL, Pará , Itaituba, 5.240183°S, 56.915383°W, 143 m, 13-xii-2012, J. Gomes (Collector).

Etymology: The epithet is derived from the Latin inopinatus, unexpected, referring to the unexpected discovery of this species in the region of the middle Tapajós River , where two other unnamed Adenomera species described in the present study had already been collected when A. inopinata was discovered (see Fig. 2).

Diagnosis: A. inopinata is characterized by the following combination of character states: (1) medium size (adult male SVL = 23.5 mm); (2) robust body shape; (3) toe tips moderately expanded (character state C); (4) distal antebrachial tubercle on underside of forearm; (5) multi-note advertisement call; (6) call notes formed by 4–5 complete pulses; (7) note duration varying from 70–91 ms; and (8) note dominant frequency coinciding with the fundamental harmonic (2109–2203 Hz).

Comparisons with congeners: A. inopinata (adult male SVL = 23.5 mm; Table 2) is smaller than A. lutzi [25.7–33.5 mm ( Kok et al., 2007)] and A. simonstuarti [25.9–26.2 mm ( Angulo & Icochea, 2010)] and larger than A. ajurauna [17.2–20.0 mm ( Berneck et al., 2008)], A. araucaria [17.4–19.3 mm ( Carvalho et al., 2019b)], A. aurantiaca (20.9 mm), A. kweti [15.4– 19.3 mm ( Carvalho et al., 2019b)], A. kayapo (17.5– 21.0 mm), A. nana [16.3–19.4 mm ( Kwet, 2007)] and A. phonotriccus [19.8–21.6 mm ( Carvalho et al., 2019c)]. A. inopinata has a robust body shape ( Fig. 12A–B), whereas A. diptyx , A. martinezi and A. saci have a slender body. A. inopinata has moderately expanded toe tips (character state C), but not fully expanded into small discs (character state D) as in A. ajurauna , A. amicorum , A. andreae , A. chicomendesi , A. heyeri , A. marmorata , A. lutzi , A. nana and A. simonstuarti , or unexpanded (character states A–B) as in A. bokermanni , A. coca , A. diptyx , A. hylaedactyla , A. martinezi , A. saci and A. thomei . A. inopinata is distinguished from congeners (except A. amicorum , A. aurantiaca , A. cotuba , A. kayapo , A. lutzi and A. phonotriccus ) by having an antebrachial tubercle on the underside of the forearm.

The advertisement call of A. inopinata ( Figs 5H, 6H, 7H; Table 3) is given as multi-note calls. Such a call pattern distinguishes the new species from congeners having single-note calls, either pulsed or non-pulsed ( Table 3). The other four Adenomera species with multi-note calls are A. aurantiaca ( Fig. 5G), A. cotuba ( Fig. 5B), A. amicorum ( Fig. 5E) and A. simonstuarti (T.R. de Carvalho, pers. obs.), from which the new species is distinguished by having call notes with complete pulses ( Figs 6H, 7H) compared to partly fused pulses in the call notes of A. amicorum ( Figs 6E, 7E), A. cotuba ( Figs 6B, 7B) and A. simonstuarti ( Table 3). From the closely related A. aurantiaca , A. inopinata is mainly distinguished by having call notes with fewer pulses per note, shorter duration and the dominant frequency coinciding with the fundamental harmonic ( Fig. 6G–H; Table 3). Call notes of these species also differ markedly in rise time, always coinciding with the first call note in A. inopinata ( A. inopinata : 1–3% of note duration; A. aurantiaca : 38–78% of note duration).

Description of holotype ( Fig. 12A–B): Body robust. Snout rounded in dorsal view, acuminate in lateral view. Nostril closer to the snout tip than to the eye, fleshy ridge on snout tip, canthus rostralis not marked, loreal region slightly concave, supratympanic fold from the posterior corner of the eye to the base of the arm, postcommissural gland ovoid, vocal slit present, vomerine teeth in two straight rows medial and posterior to choanae and oblique to sagittal plane. Tongue elongated, free from the posterior half. Relative finger lengths I <II ≃ IV <III, fingers without ridges or fringes, finger tips rounded, slightly expanded, especially fingers III and IV, inner metacarpal tubercle elongated, outer metacarpal tubercle rounded. Subarticular tubercles nearly rounded or rounded, supernumerary tubercles rounded. Antebrachial tubercle on underside of forearm, single, rounded. Dorsum mostly smooth, flank and inguinal region glandular. Posterior surface of thigh granular contiguous with the ventral surface. Paracloacal gland divided, nearly rounded to ovoid. Ventral surface of body and limb smooth. Relative toe lengths I <II <V <III <IV, lateral fringing and webbing absent, tips of toes II–IV moderately expanded (character state C), tips of toes I and V unexpanded. Inner and outer metatarsal tubercles ovoid, inner tubercle twice the maximum diameter of the outer tubercle. Tarsal fold low, extending 2/3 of tarsus length, from the inner metatarsal tubercle towards the heel, ending in a tubercle separated from the fold by a short gap. Subarticular tubercles nearly rounded or subconical, supernumerary tubercles rounded. Measurements are given in Table 2.

Snout tip with a faded white coloration (coincident with the fleshy ridge). Blotches on the upper lip white. Postcommissural gland cream-coloured medially and surrounded by brown coloration. Tympanum light brown. Dorsal surface of body and limbs light brown with dark brown blotches, spots and stains. Interorbital bar dark brown. Dorsal surface of limbs with interrupted transverse bars and blotches dark brown. Posterior surface of thigh pale yellow laterally, dark brown in the cloacal region, paracloacal gland pale yellow and dark brown. Mid-dorsal longitudinal stripe and dorsolateral stripes absent. Ventral surface of belly and thigh partially translucent, yellowish cream. Throat and chest brown-mottled. Belly mostly immaculate, with brown mottling laterally. Underside of forearm (outer margin), palm of hand, sole of foot and digits brown interspersed with lighter sections in grey and cream, subarticular tubercles partly pigmented, tips of fingers and toes non-pigmented.

Colour of holotype in life ( Fig. 10A–B): Dorsum covered with dark brown stains and spots irregularly distributed on a light brown background. Iris copper. Tympanum brown. Groin yellow. Postcommissural gland orange. Arms and legs with dark brown transverse stripes and stains on a reddish brown background. Information on life colours in ventral view was not assessed.

Advertisement call: Description based on calls of one male (N = 13 notes and 57 pulses quantified; Table 3). The call ( Figs 5H, 6H, 7H) consists of a multi-note signal given twice per minute (based on a brief sound recording). Calls are composed of 5–10 (8 ± 4) notes given at a rate of four per second. Notes are formed by 4–5 (4 ± 1) complete pulses given at a rate of 58–63 (60 ± 1) per second and varying in duration from 5–30 (14 ± 1) ms. Note duration varies from 70–91 (79 ± 7) ms and note rise time from 1–3 (2 ± 1)% of duration. The note frequencies are harmonically structured and the dominant frequency coincides with the fundamental harmonic (2109–2203, 2189 ± 35 Hz). Frequency modulation is upward, rising 188–656 (526 ± 151) Hz.

Habitat and natural history: Due to the rarity of A. inopinata at the type locality, we do not have enough data to describe general aspects of the natural history and preferred calling habitat of the species. The single individual that has been recorded to date was found calling on the leaf litter of a primary non-flooded forest during the rainy season (December). The exact type locality is a location of difficult access because of the irregular terrain of rocky outcrops. It is located about 2.5 km away from the east margin of the Tapajós River. A. andreae is the only syntopic congener of A. inopinata at the type locality, much more abundant than the new species in the region.

Distribution: A. inopinata is known only from the type locality in the Tapajós-Jamanxim interfluve. A. inopinata occurs west of the Jamanxim River, w h e r e a s t h e cl o s e s t r e l a t e d (a n d p r e s u m a b l y allopatric) A. aurantiaca occurs on the opposite river bank ( Fig. 2B).

Remarks: It is relevant to highlight the rarity of A. inopinata at the single location where the species is known to occur. Regardless of extensive sampling effort at the type locality of A. inopinata at the middle Tapajós River during two years [see detailed information in Moraes et al. (2016)], only a single male was ever recorded and collected.