Chiasmocleis abofoa, Rojas-Padilla & Gagliardi-Urrutia & Rios-Alva & Castroviejo-Fisher, 2022

Rojas-Padilla, Omar, Gagliardi-Urrutia, Giussepe, Rios-Alva, Ehiko J. & Castroviejo-Fisher, Santiago, 2022, A new species of Chiasmocleis Méhely, 1904 (Anura: Microhylidae) from the Peruvian Amazonia, Zootaxa 5195 (1), pp. 24-50 : 27-32

Chiasmocleis abofoa sp. nov.

Figs. 3–15 .

Suggested English common name: ABOFOA’s Humming frog.

Suggested Spanish common name: Rana de hojarasca de ABOFOA.

Chiasmocleis sp. nov. Rios-Alva et al. (2015).

Holotype. CRBIIAP 2507 [ MCP 14084] (field number GGU 3289 ), an adult female from “ Asociación Bosques del Futuro Ojos de Agua ” (6°50′50.36″ S, 76°27′47.75″ W, 364 m a.s.l.), district of Pucacaca, province of Picota, department of San Martin, Peru, collected by Ehiko J. Rios-Alva, Giussepe Gagliardi-Urrutia, and Omar RojasPadilla, on September 5, 2015, at 22:15 h.

Paratopotypes. CRBIIAP 2506 [ MCP 14083] (field number GGU 3288 ), an adult male; CRBIIAP 2508 [ MCP 14085] ( GGU 3290 ), CRBIIAP 2509 [ MCP 14086] ( GGU 3295 ), CRBIIAP 2510 ( GGU 3296 ), CRBIIAP 2511 ( GGU 3301 ), CRBIIAP 2512 ( GGU 3303 ), all adult females with the same data as holotype .

Paratype. MUSM 40928 ( GGU 6483 ) an adult female collected by Omar Rojas-Padilla, Giussepe GagliardiUrrutia, Ramon Aguilar-Manihuari, and Wendy del Castillo-Garay on June 17, 2021, within the same conservation area (06º51′38.8″ S, 76º26′29.2″ W, 311 m asl) .

Remarks on the type series. Most Chiasmocleis name-bearing types are adult males. However, we chose an adult female over the single male because the latter specimen is not in a good state of preservation. It shows skin tears in the frontoparietal, nostrils, right ocular, and left hand FIII regions. This compromises its preservation in the long term. Furthermore, all adult females show diagnostic characters shared with the single male as discussed below, and DNA sequences of females and the single male are virtually identical, supporting the correct assignment of both sexes to the same species.

Etymology. The specific name is the acronym of the local association that protects the habitat of the new species. By naming this species after the Asociación Bosques del Futuro Ojos de Agua we want to acknowledge and highlight this self-managed conservation initiative that has been working for more than a decade.

Generic placement. A member of Chiasmocleis based on: (1) absence of occipital fold; (2) clavicle reduced not reaching the glenoid region; (3) quadratojugal and maxilla not in contact; (4) vomers present ( Peloso et al. 2008; Funk & Cannatella 2009; Forlani et al. 2017). Furthermore, our optimal phylogenetic tree placed the new species well-nested within the genus ( Fig. 2 ).

Characterization. The new taxon is characterized by the unique combination of the following character states: (1) medium sized adults, male SVL = 16.5 mm (n = 1), female SVL = 18.2–20.8 mm (n = 7); (2) body ovoid and robust in females, slenderer in the male, (3) head triangular, snout rounded in dorsal and lateral views, IOD 2.0–2.6 (2.2 ± 0.2) times of IND; (4) four distinctive fingers, extensively fringed in the male, hardly in females, finger I well developed with a distinct subarticular tubercle, distinct subarticular tubercles present on all fingers, relative finger length I <II <IV <III; (5) five toes present, all strongly fringed in the male, hardly fringed in females, toes without webbing in both sexes, relative toe length I <II <V <III <IV; (6) male with dermal spines on fingers and toes, ventral surfaces of feet, dorsal and ventral surface of body, and upper jaw, absent in females; (7) dermal spines around the cloacal region in both sexes; (8) dermal spines on chin absent in both sexes; (9) vocal slits present in male; (10) femoral line present; (11) eight procoelus presacral vertebrae; (12) sacral diapophyses expanded; (13) urostyle with lateral expansions in the anterior part; (14) falange formula of hand and foot 2-2-3-3 and 2-2-3-4-3, respectively; (15) pigmented testes; (16) males without dark gular region.

Description of the holotype. An adult female in good state of preservation ( Fig. 3 ), with a piece of tissue removed from the right thigh and the liver, through a ventral cut on the left anterior side of the venter, and preserved as tissue samples for molecular analyses. Measurements are in Table 1 . Body ovoid, robust; head short, triangular, snout short, wider than long, rounded in dorsal and lateral views; nostril protuberant; internarinal distance, distance between the eye and nostril, and the eye diameter is the same; canthus rostralis weakly defined; loreal region slightly convex; eyes small; interorbital area slightly concave, without cranial crests; occipital and postorbital fold absent; tympanum not visible externally; upper jaw more projected that the lower; lower lip with truncate, trilobed anterior margin; tongue large, ovoid, with free lateral and posterior borders; premaxillae, maxillae, and vomerine teeth absent; circular choanes widely separated, located anteriorly of the eye.

Arm and forearm slender, without tubercles or crest. Hands not webbed, fingers slightly fringed and without dermal spines; FI well developed, with a circular subarticular tubercle; relative finger length I <II <IV <III, fingers lacking disks. Subarticular tubercles well defined, nearly rounded; supranumerary tubercles absent; palmar tubercle rounded and not divided; thenar tubercle elliptical, at base of FI.

Added values of THL, TBH, and FL 2.35 times the SVL, legs lacking tubercles; tibial and tarsal ridges absent; foot without web; toes lacking disks, slightly fringed; inner metatarsal tubercle present, oval, other metatarsal supranumerary tubercles absent; toes lack dermal spines; relative toe length I <II <V <III <IV; skin smooth with dermal spines around the cloacal region.

Color of the holotype. In life ( Fig. 4 ) dorsal and lateral surfaces of body uniformly brown with small scattered white spots and darker brown flecks; dorsal surfaces of limbs with the same pattern, although with a higher concentration of white spots and dark flecks. Posterior side of thighs with a white femoral line extending from cloaca through thighs. Ventral and gular regions white, with a mottled grey pattern. Ventral surface of thighs with a similar pattern but with smaller spots and duller colors. Palms of hands and feet uniform brown. Bronze-reddish iris. The same color patterns remained in preservative ( Fig. 3 ).

Variation. We summarized morphometric variation in Table 1 . The only collected male ( Fig. 5 ) shows marked sexual dimorphism in size (SVL 16.5 mm vs 18.2–20.7 mm in females); dermal spines (present on upper jaw, dorsal region, limbs, lateral fringes of fingers III, IV, and toes, and the cloacal region vs present only on the cloacal region of females but in fewer number); and extension of fringes in fingers and toes (well-developed in male vs poorly developed in females) ( Fig. 6 ). Also, a small protuberance on the front of the snout between the nostrils is visible in dorsal and lateral view on all specimens except the single male. Variation in ventral color patterns is illustrated in Fig. 7 .

Osteology. The description is based on 3D CT-scan models of the mineralized skeleton of two paratypes, a male (CRBIIAP 2506, MorphoSource M000446038) and a female (CRBIIAP 2509, MorphoSource M000446042), and unless otherwise stated, the description refers to both specimens, while all illustrations are of CRBIIAP 2506.

Figures

FIGURE 2. Phylogenetic relationships of Chiasmocleis inferred from a maximum likelihood analysis of 2373 bp of the concatenated mitochondrial and nuclear genes 16S, COI, TYR, and BDNF. Terminals of the new species are highlighted in red. Numbers on branches are Bootstrap values> 50 %, while 100 % values are represented by asterisks.

FIGURE 3. Detailed views of the holotype of Chiasmocleis abofoa sp. nov. (CRBIIAP 2507). Head in dorsal (A), ventral (B), and dorsolateral (C) views; ventral views of the right foot (E) and left hand (F). Scale bars = 1 mm.

FIGURE 4. Holotype adult female of Chiasmocleis abofoa sp. nov. (CRBIIAP 2507) in life. Dorsolateral (A), ventral (B), and dorsal (C) views.

FIGURE 5. Adult male paratype of Chiasmocleis abofoa sp. nov. (CRBIIAP 2506) in life. Dorsolateral (A), ventral (B), and dorsal (C) views.

FIGURE 6. Detailed views of different regions of the head, testes, and limbs of the adult male paratype of Chiasmocleis abofoa sp. nov. (CRBIIAP 2506). Lateral view of the head (A), postocular region (B), upper jaw (C), pigmented testes (D), left hand palm (E), finger IV (F), and right foot sole (G). White arrows point to dermal spines in (C) and (F), and point testes in (D). Scale bars = 1 mm.

FIGURE 7. Variation of the ventral pattern of the type series of Chiasmocleis abofoa sp. nov.

FIGURE 8. Skull of the adult male paratype of Chiasmocleis abofoa sp. nov. (CRBIIAP 2506) in dorsal (A), ventral (B), lateral (C) and frontal (D) views. Abbreviations: exo = exoccipitals, fpar = frontoparietal, max = maxilla, nas = nasals, op for = optic foramen, oper = operculum, pmax = premaxilla, prsph = parasphenoid, prsph.al = parasphenoid alae, prsph.cp = parasphenoid cultriform process, pter = pterygoid, pro = prootic, qj = quadratojugal, sphe + npl = sphenethmoids + neopalatines, spmax = septomaxillae, sta = stapes, sq = squamosal, sq.or = squamosal otic ramus, sq.zr = squamosal zygomatic ramus, vom = vomers. Scale bar = 1 mm.

FIGURE 9. The posteriomedial hyoid process (left) and mandible (right) of the adult male paratype Chiasmocleis abofoa sp. nov. (CRBIIAP 2506). Abbreviations: angspl = angulosplenial, mmk = mentomeckelian bone. Scale bar = 1.0 mm

FIGURE 10. Vertebral column with numbered presacral vertebrae of the adult male paratype of Chiasmocleis abofoa sp. nov. (CRBIIAP 2506). Scale bar = 1 mm.

FIGURE 11. Pectoral girdle of the adult male paratype of Chiasmocleis abofoa sp. nov. (CRBIIAP 2506).Abbreviations: cor = coracoides, cla = clavicles, cle = cleitrum, sca = scapule. Scale bar = 1 mm.

FIGURE 12. Forelimb and manus of the adult male paratype of Chiasmocleis abofoa sp. nov. (CRBIIAP 2506). Ventral view of the right hand with numbered fingers (A), ventral and lateral view of the humerus (B), ventral view of the radioulna (C). Abbreviations: C = distalcarpals, cr.ven = crista ventralis, e.cap = eminentia capitata, S = seismoids, pp = prepollex. Scale bar = 1 mm.

FIGURE 13. Pelvic girdle on dorsal (top) and lateral (bottom) views of the adult male paratype of Chiasmocleis abofoa sp. nov. (CRBIIAP 2506). Abbreviations: il.dp = dorsal prominence of the ilium. Scale bar = 1 mm.

FIGURE 14. Hindlimb and pes of the adult male paratype of Chiasmocleis abofoa sp. nov. (CRBIIAP 2506). Ventral view of the left foot with numbered toes (A), ventral view of the femur (B), ventral view of the tibiofibular (C), ventral view of the tibiale-fibulare (D). Abbreviations: T = tarsals, ph = prehallux, S = seismoids, tf.sif = sulcus intermedius of tibiofibula. Scale bar = 1 mm.

FIGURE 15. Individuals of Chiasmocleis abofoa sp. nov. on a pond in their natural habitat. Two females non-collected females (A) and the male paratype, CRBIIAP 2506, (B) floating near to palm tree leaves.