Adenomera amicorum, 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 : 413-416

ADENOMERA AMICORUM , SP. NOV.

SANTARÉM TERRESTRIAL NEST- BUILDING FROG

( FIGS 2B, 3– 4, 5E, 6E, 7E, 9C–D, 11C–D;

TABLES 1-3)

lsid urn:lsid:zoobank.org:act:EF6EBAF5-D891-4729-B832-B3F3994BDB05

Holotype: INPA-H 40506 (field # APL 122325 ), adult male, BRAZIL, Pará , Belterra, Fazenda Treviso, 3.149111°S, 54.840278°W, 104 m, 12-ii-2007, A.P. Lima (Collector).

Paratypes: CFBH 44465–44469 (field # APL 122328– 31 , 122333 , respectively) , INPA-H 40490–40499 , 40501–40505 , 40507–40508 (field #19A–22A, APL 122305 , 122311 , 122313–16 , 122319–21 , 122323–24 , 122326–27 , respectively), adult males, and INPA-H 40500 (field # APL 122317 ), adult female, collected at the type locality between 2004–2007, A.P. Lima (Collector) . INPA-H 40509–40510 (field # APL 22086, 22171 , respectively), adult males, BRAZIL, Pará , Belterra , Área de Preservação Ambiental ( APA) Alter do Chão, 3.516944°S, 55.073056°W, 155 m, 19-iii-2017, A.P. Lima (Collector) .

Referred specimens: The genetic voucher MTR 11092: BRAZIL, Pará , Belterra, FLONA do Tapajós .

Etymology: The epithet is derived from Latin amica, friend, as a plural noun in apposition. The name is a reference to the members of the ‘ Allobates femoralis project’ led by one of us (A.P.L.) throughout Brazilian Amazonia. The research team was out in the field at the type locality of the species when it was first discovered in the early 2000s.

Diagnosis: A. amicorum is characterized by the following combination of character states: (1) medium size (adult male SVL = 20.9–24.0 mm); (2) robust body shape; (3) toe tips moderately to fully expanded (character states C–D); (4) distal antebrachial tubercle on underside of forearm; (5) two possible chromotypes (presence/absence) of dorsolateral stripe; (6) multinote advertisement call; (7) call notes formed by 4–10 partly fused pulses; (8) note duration varying from 133– 197 ms; (9) note dominant frequency coinciding with the second harmonic (3898–4221 Hz); and (10) note fundamental frequency ranging from 1958–2110 Hz.

Comparisons with congeners: A. amicorum has adult males (SVL = 20.9–24.0 mm; Table 2) smaller than those of A. lutzi [25.7–33.5 mm ( Kok et al., 2007)] and A. simonstuarti [25.9–26.2 mm ( Angulo & Icochea, 2010)]. A. amicorum has a robust body shape ( Fig. 11C– D), whereas A. diptyx , A. martinezi and A. saci have a slender body ( Carvalho & Giaretta, 2013b). A. amicorum has toe tips moderately (character state C) or fully expanded into small discs (character state D), whereas the toe tips are unexpanded (character states A–B) in A. bokermanni , A. coca , A. diptyx , A. hylaedactyla , A. martinezi , A. saci and A. thomei . A. amicorum is distinguished from most congeners (except A. cotuba , A. kayapo , A. lutzi and A. phonotriccus ) by having an antebrachial tubercle on underside of forearm. A. amicorum is distinguished from A. cotuba , which does not have a dorsolateral stripe, by the occurrence of two possible chromotypes (presence/absence) of the stripe. A. amicorum can be distinguished from the closely related A. kayapo and A. phonotriccus by having toe tips moderately to fully expanded (unexpanded or slightly expanded in the other two species). However, these three species are more easily distinguished from each other based on their calls. The advertisement call of A. amicorum ( Figs 5E, 6E, 7E; Table 3) is given as multinote calls. Such a call pattern distinguishes the new species from congeners having single-note calls, either pulsed or non-pulsed ( Table 3). The other two species of Adenomera with multi-note calls are A. cotuba ( Fig. 5B) and A. simonstuarti (T.R. de Carvalho, pers. obs.), from which the new species is distinguished by having call notes with higher frequencies in the first two harmonics and with longer duration, respectively ( Table 3).

Description of holotype ( Fig. 11C–D): Body robust. Snout subovoid to 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 rounded; loreal region slightly concave; supratympanic fold from the posterior corner of the eye to the base of the arm; postcommissural gland elongated; vocal sac subgular with a fold from jaw extending to forearm, 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 IV ≃ I <II <III; fingers without ridges or fringes; finger tips rounded, slightly expanded; inner metacarpal tubercle ovoid; outer metacarpal tubercle nearly rounded. Subarticular tubercles rounded or nearly rounded; supernumerary tubercles rounded. Antebrachial tubercle on underside of forearm, single, rounded. Anterior dorsum and forelimb smooth; posterior dorsum and flank warty; tubercles sparsely distributed on posterior dorsum, dorsal surface of hindlimb and posterior surface of tarsus. Dorsolateral fold absent. Paracloacal gland indistinct; lumbar gland rounded. Ventral surface of body and limb mostly smooth; underside of thigh granular. 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 metatarsal tubercle ovoid, outer metatarsal tubercle nearly rounded, inner tubercle twice the maximum diameter of the outer tubercle. Tarsal fold extending 1/2 of tarsus length, from the inner metatarsal tubercle towards the heel, with a short gap close to the tubercle. Subarticular tubercles nearly rounded or subconical; supernumerary tubercles nearly rounded. Measurements (in mm): SVL 21.7, HL 6.8, HW 8.1, ED 1.9, TD 1.3, EN 1.6, IND 1.9, HAL 4.4, TL 9.5, THL 8.9, FL 10.0.

Snout tip with a faded white coloration (coincident with the fleshy ridge). Blotches on the upper lip faded white. Postcommissural gland cream-coloured. Tympanum light brown. Dorsum and dorsal surface of hindlimb brown on a light brown background. Flank speckled in light brown on a light grey background. Posterior surface of thigh finely mottled in shades of brown and yellow. Mid-dorsal longitudinal stripe and dorsolateral stripes absent. Paracloacal gland pale yellow, covered with melanophores. Ventral surface of belly and thigh partially translucent, yellowish cream. Blotches on lower jaw white. Throat and anterior chest brown-dotted and white-spotted. Fine mottling (brown) faded. Underside of forearm brown. Ventral surface of hand, foot and digits have brown, subarticular and supernumerary tubercles, and tips of fingers and toes are cream-coloured and light grey. Brown spotting sparsely distributed on thigh.

Variation in type specimens: Overall coloration is faded in the specimens INPA-H 40490–93 . Their throat varies in brown mottling intensity. INPA-H 40494 has snout subovoid to subelliptical in dorsal view; throat coloration faded; paracloacal gland absent. The female INPA-H 40500 has snout nearly rounded from above, rounded in profile; dorsolateral fold pale yellow, indication of mid-dorsal longitudinal stripe, paracloacal gland absent; hindlimbs mostly smooth. Dorsolateral folds and/or stripes are present in INPA-H 40497 , 40500 , 40502–04 , 40507 , 40509 . Tips of toes II– IV vary between moderately to fully expanded (character states C–D) in CFBH 44468–69 , INPA-H 40490–98 , 40500 and 40502, and are fully expanded (state D) in INPA-H 40499 , 40501 and 40505. Paracloacal and lumbar glands, and antebrachial tubercles may be low or flattened, and have the same colour of background dorsal/ventral coloration, which make them difficult to observe even under magnification. The holotype was not photographed in life; however, life colours of a paratype are shown in Fig. 9C–D .

Advertisement call: Description based on calls of three males (N = 134 notes and 980 pulses quantified; Table 3). The call ( Figs 5E, 6E, 7E) consists of a multinote signal given a few times (2–7) per minute. Calls are composed of 3–9 (5 ± 2; N = 3) notes given at a rate of 1–2 (2 ± 1; N = 3) per second. Notes are formed by 4–10 (7 ± 1) partly fused pulses given at a rate of 43–67 (51 ± 4) per second and varying in duration from 3–62 (22 ± 1) ms. Note duration varies from 133–197 (162 ± 6) ms and note rise time from 38–74 (55 ± 4)% of note duration. The note frequencies are harmonically structured and the dominant frequency coincides with the second harmonic (3898–4221, 4047 ± 38 Hz). The note fundamental frequency ranges from 1958–2110 (2029 ± 42) Hz. Frequency modulation is upward in most cases, with a few calls modulating slightly downward, varying from –129 to 1206 (330 ± 367) Hz.

Habitat and natural history: Several males of A. amicorum were heard calling hidden under the leaf litter in an old-growth non-flooded forest during daytime throughout most of rainy season (November to March). A. andreae and A. hylaedactyla are sympatric with the new species at the type locality.

Distribution: A. amicorum is known from the type locality and FLONA Tapajós, both within the municipal limits of Belterra ( Fig. 2B). The species was also acoustically registered from other localities on the east bank of the lower Tapajós River (Rurópolis, Placas and Uruará) ; however, recordings and tissue samples are not available for the confirmation of these occurrence points for the species.

Remarks: There is a single specimen from the west bank of the Xingu River associated with the lineage sp. F2 (= A. amicorum ), the genetic voucher BM 23 from UHE Belo Monte, in Vitória do Xingu (Supporting Information, Appendix S2). The genetic divergence between this specimen and type specimens of A. amicorum matches exactly the 5% threshold of interspecific divergence in our species delimitation analysis ( Table 1). Further information, especially sound recordings, will be required for an accurate assessment of the taxonomic identity of the Xingu population. For the moment, the voucher BM 23 is pending a definite species assignment, referred herein to as A. cf. amicorum .