Microkayla chapi, Riva & Chaparro & Castroviejo-Fisher & Padial, 2018

MICROKAYLA CHAPI View in CoL SP. NOV.

( FIG. 9)

urn:lsid:zoobank.org:act:A11DB6F2-E959-4570-A369-00A7D64C8E13

Holotype: MUBI 5326 (field number 4516), adult female from 3.7 km from Sina, Hirigache River valley, province Sandia , department Puno, Peru, 14°30 ′ 09.7 ″ S, 69°15 ′ 44.3 ″ W, 3504 m ( Fig. 10), collected on 10 February 2006 by I. De la Riva, J. M. Padial, S. Castroviejo-Fisher, J. C. Chaparro, and J. Bosch. GoogleMaps

Paratopotypes: MUBI 5325 , 5327 , 5330 , 5331 (field numbers 4514, 4519, 4524, 4527) , MNCN 43763–65 About MNCN and 43767–69 (males) (field numbers 4515, 4517, 4518, 4522, 4525, 4526) ; MNCN 43762 About MNCN and 43766 (field numbers 5183 and 5191) (females); and MUBI 5328 , 5329 (field numbers 4520, 4523) (juveniles), same data as the holotype GoogleMaps .

Diagnosis: Microkayla chapi is characterized by: (1) skin on dorsum shagreen with large scattered sharp warts and short folds, sometimes coalescing into a pair of dorsolateral folds and/or incomplete middorsal and occipital folds; dorsal surface of extremities warty; flanks uniformly warty; ventral skin areolate, throat areolate; (2) tympanic membrane and tympanic annulus evident beneath the skin, supratympanic fold conspicuous; (3) snout short, rounded in dorsal and lateral views; (4) upper eyelid lacking tubercles, bearing small conical warts; (5) dentigerous process of vomers absent; (6) vocal slits and sac present, subgular; nuptial pads absent; (7) Finger I slightly shorter than Finger II; tips of digits rounded, lacking circumferential grooves and ungual flap; (8) fingers lacking lateral fringes; (9) ulnar region bearing warts, sometimes coalescing into a sharp ridge; (10) heel lacking tubercles, tarsus lacking tubercles and folds; (11) plantar surfaces of feet bearing two metatarsal tubercles, inner slightly larger than outer; supernumerary plantar tubercles low, inconspicuous; (12) toes lacking lateral fringes; webbing absent; Toe III slightly longer than V, tips of digits rounded, lacking circumferential grooves and ungual flap; (13) dorsal coloration with various shades of reddish-brown to dark brown or grey with metallic tones; ventral coloration variable, from grey with shades of red to dark grey with yellow spots; distal portions of hands and feet orange to red; groin with orange or red flash marks; (14) females slightly larger than males, SVL 19.9–21.6 in adult females (n = 3), 16.3–19.1 mm in adult males (n = 9) ( Table 3).

Microkayla chapi sp. nov. is readily distinguished from both M. boettgeri and M. chilina sp. nov. (the two other Peruvian species) by having sharp and well-developed dorsolateral folds, occipital and sacral sharp warts and folds, a large and conspicuous tympanic membrane that is longer than 50% of eye length, and longer toes, less areolate belly, and smooth to granular skin. On the Bolivian side of the Cordillera of Apolobamba, the species M. chaupi and M. katantika occur 37.6 and 39.8 km straight line distance, respectively, from M. chapi . Microkayla chapi differs from M. chaupi mostly by having conspicuous dorsolateral folds (absent in P. chaupi ), ventral coloration variable from grey with shades of red to dark grey with yellow spots (uniformly greyish-brown) and ventral skin areolate (finely granular). Microkayla chapi differs from M. katantika by being smaller (maximum SVL in M. chapi 21.6 mm, 27.7 mm in M. katantika ), having dorsolateral folds (absent) and dorsal and ventral coloration variable (uniformly dark brown or grey). In addition, M. chapi can be distinguished from all other species of Microkayla by its sharp dorsal ridges and warts, a conspicuous tympanic membrane, and red flash marks in the groin.

Description of the holotype: An adult female, 19.9 mm SVL. Body robust; dorsal skin shagreen, with irregular warts scattered all over, and a pair of dorsolateral folds becoming inconspicuous ridges at level of midbody; ventral skin areolate pectoral fold absent; head wider than long, HW 34.7% of SVL, HL 31.1% of SVL; snout moderately short, rounded in dorsal view and in profile; nostrils not prominent, slightly closer to snout than to eyes; canthus rostralis sharp, straight in dorsal view and lateral profile; eye-nostril distance 58.3% of eye length; loreal region faintly concave; cranial crests absent; tympanic membrane and tympanic annulus perceptible beneath skin; supratympanic fold prominent; tongue large, oval; choanae small, broadly separated; dentigerous processes of vomers absent; limbs short; fingers short, lacking fringes, tips of digits round, lacking circumferential grooves and ungual flap; ulnar tubercle and fold absent, but a row of low warts forming a ridge; inner palmar tubercle oval, smaller than round outer; fingers moderately short, not fringed; subarticular tubercles of the base of fingers large, round, swollen; supernumerary tubercles round, barely visible; relative length of fingers 1 <2 <4 <3; tibia length 30.1% of SVL; tarsal fold absent; two metatarsal tubercles, oval inner slightly smaller than round outer; supernumerary tubercles round, poorly marked; subarticular tubercles round; toes lacking basal webbing or lateral fringes, toe tips round, lacking circumferential groves and ungual flap; relative length of toes 1 <2 <3 = 5 <4; foot length 36.2% of SVL.

In preservative, dorsum brown with a pale middorsal thin line; venter and throat mostly cream with irregular brown areas; a pair of large and conspicuous bold black lumbar spots surrounded by a thin white line; a white thin line along posterior surface of thigh, from cloaca to level of shanks; axillae, groins and inner surface of forearms and shanks cream. In life, the dorsum was mostly uniformly brown above, with some pale areas; it had small reddish-orange irregular areas on axillae and groins; the venter was pale brown with irregular darker areas; the digits were reddish-orange; the iris was dark brown below and greenish-yellow in the upper third, with fine black reticulation.

Measurements (in mm) of the holotype: SVL, 19.9; HL, 6.2; HW, 6.9; IND, 1.6; END, 1.4; ED, 2.4; TL, 6.0; FL, 7.2.

Variation: The holotype has less warty dorsal skin, but other specimens have larger and sharper warts and short folds, sometimes forming short discontinuous dorsolateral or middorsal ridges ( MUBI 5327 , 5328 ) . The overall coloration is more or less similar in all specimens examined, while venter varies from almost uniformly cream ( MUBI 5331 ) to almost uniformly dark greenish-brown ( MUBI 5325 , 5330 ) and all intermediate patterns; the throat varies from cream ( MUBI 5329 ) to brown ( MUBI 5330 ) ; the pale lines of the posterior surface of thighs can be absent ( MUBI 5330 ) ; some specimens have an inguinal dark spot ( MNCN 43765 About MNCN , 43766 About MNCN ) ; the tympanic annulus can be appreciable beneath the skin ( MUBI 5330 ) or not ( MUBI 5327 ) . For morphometric variation, see Table 3.

Distribution and natural history: Known only from the type locality. Individuals were found by day under stones, in highly humid wet puna/elfin forest, and were common in only a very small area (c. 3 has), but no individuals were found beyond that point, despite the same kind of habitat being found over a larger area ( Fig. 11). At night, with mist and full moon and an air temperature of 10 °C, males called with low intensity from inside moss on the ground and on stones. The call consisted of a single non-pulsed note, modulated in amplitude, with most intensity distributed between 3000 and 3300 Hz, a duration of 72–91 ms, emitted at a rate of 2.6–10.4 notes/minute ( Fig. 12, Table 4) (call record number 8217, www.fonozoo.com).

Etymology: The species epithet is used as a name in apposition, and derives from the word ‘chapi’, meaning tin in Quechua, or ‘Ch ′ api’, meaning thorn in Aymara. We use the two meanings of chapi to refer to the ‘thorns’ in the skin of the new species and to the tin roofs of the miner’s shacks in ‘La Rinconada’ (5100 m), a gold mine and the highest village in the world, close to the type locality of this species. Chapi is also the name of a mountain (5400 m) near La Rinconada, on the border of the districts of Ananea and Sina, in the cordillera of Apolobamba.