Phrynoglossus myanhessei Koehler , Vargas, Than & Thammachoti, 2021

Koehler, Gunther, Vargas, Joseph, Than, Ni Lar, Schell, Tilman, Janke, Axel, Pauls, Steffen U. & Thammachoti, Panupong, 2021, A taxonomic revision of the genus Phrynoglossus in Indochina with the description of a new species and comments on the classification within Occidozyginae (Amphibia, Anura, Dicroglossidae), Vertebrate Zoology 71, pp. 1-26 : 1

Phrynoglossus myanhessei Koehler, Vargas, Than & Thammachoti sp. nov.

Figs 8 , 9 , 10

Holotype.

SMF 103841, an adult male collected at East Yangon University (16.77737, 96.24065; 17 m a.s.l.), Thanlyin, Yangon, Myanmar, collected 6 July 2017 by Gunther Köhler and Ni Lar Than. Field tag number GK-6728.

Paratypes.

SMF 103840, same collecting data as holotype; SMF 103797-99, same locality data and collectors as holotype but collected 15 June 2018. All paratypes are adult males except for SMF 103798 which is an adult female.

Diagnosis.

A species of the genus Phrynoglossus as defined above that differs from all mainland Southeast Asian congeners by having (1) a large body size (males 22.0-27.4 mm; females 28.4-31.3 mm); (2) relatively small tympanum (ratio TYD/SVL 0.48-0.92); and (3) call duration of male advertisement call 85-114 ms. Phrynoglossus myanhessei differs from its congeners in Indochina (i.e., P. martensii and P. magnapustulosus ) in the male advertisement call, most obvious in call duration (85-114 ms in P. myanhessei , 32-52 ms in P. martensii , 243-437 ms in P. magnapustulosus ) and dominant frequency (2454-2885 Hz in P. myanhessei , 3338-3962 Hz in P. martensii , 3187-3790 Hz in P. magnapustulosus ).

Comparisons.

Phrynoglossus myanhessei differs from its congeners as follows (condition for P. myanhessei in parentheses). Phrynoglossus floresianus , P. semipalmatus , and P. tompotika all have distinctly enlarged flattened toe and finger disks (tips of toes rounded, only slightly expanded into discs, not distinctly flattened); P. floresianus and P. laevis are much larger frogs, 35-37 mm in males, 40-51 mm in adult females in P. floresianus , 26-42 mm in males, 35-62 mm in females in P. laevis (males 22.0-27.4 mm; females 28.4-31.3 mm); furthermore, the eyes are directed dorsolaterally in P. laevis and P. celebensis (laterally); P. baluensis usually has a large inverted U-shaped ridge on the dorsum (no such ridge present) and reduced toe webbing with at least two phalanges free of webbing along fourth toe (feet almost fully webbed, less than one phalange free of webbing along fourth toe); P. sumatranus has a dark brown band on each side of the cloaca (such band absent), diamond shaped pupil (ovoid), and its eyes are oriented dorsolaterally (laterally); P. diminutivus has reduced toe webbing with two phalanges free of webbing along fourth toe (feet almost fully webbed, less than one phalange free of webbing along fourth toe); P. martensii and P. magnapustulosus are smaller frogs, 20-23 mm in males, 26-30 mm in adult females in P. martensii , 17-20 mm in males, 17-24 mm in females in P. magnapustulosus (males 22.0-27.4 mm; females 28.4-31.3 mm); furthermore, P. magnapustulosus has a relatively larger tympanum, ratio tympanum/SVL 0.055-0.099, mean 0.082 (0.029-0.066, mean 0.050). Also, P. martensii has a relatively broader head, ratio HW/SVL 0.336-0.401, mean 0.357 in males, 0.338-0.388, mean 0.351 in females (0.286-0.369, mean 0.338 in males, 0.283-0.354, mean 0.312 in females).

Description of the holotype

(Figs 8 and 9 ). Adult male, as indicated by dark colored throat region and presence of vocal slits; SVL 23.56 mm; habitus robust; head broad, about as wide as long, ratio HL/HW 1.06; snout nearly rounded in dorsal view, projecting beyond lower jaw, rounded in profile; nostril dorsolateral, closer to tip of snout than eye; canthus rounded; ratio EYD/SVL 0.12; IOD (2.12) greater than width of upper eyelid (1.94); tympanum concealed, slightly depressed relative to skin of temporal region, tympanic rim weakly elevated relative to tympanum; ratio TYD/EYD 0.42; vomerine teeth absent; tongue fleshy, rounded, without notch; tips of all four fingers rounded, not expanded into discs; relative finger lengths III>I>IV>II; no webbing; distinct subarticular tubercles, palmar tubercle distinct, bifid; thenar tubercle large, about twice the size of palmar tubercle; tips of toes rounded, slightly expanded into discs; relative toe lengths IV>III>V>II>I; feet almost fully webbed, webbing formula I 0.8-0.8 II 0.8-0.8 III 0.8-0.9 IV 0.9-0.8 V; a well-developed flap of skin on postaxial side of Toe V from level of outer metatarsal tubercle to distal subarticular tubercle; strong fold on distal one-half of tarsus; large, flap-like inner metatarsal tubercle; outer metatarsal tubercle not differentiated, but rather two tiny tubercles present in that area; skin on top of head and on dorsum and flank smooth; skin on throat and venter shagreen; skin on upper surface of forelimbs and thigh with low, rounded tubercles, that of dorsal surface of shank with scattered keratinized pointed tubercles; indistinct, glandular supratympanic fold from posterior edge of upper eyelid along upper margin of tympanum and then obliquely down to shoulder; no dorsolateral fold. Measurements (mm) of holotype: SVL 23.56; HL 8.91; HW 8.44; SL 3.60; EYD 2.81; IOD 2.12; TYD 1.17; TED 0.67; SHL 12.51; THL 12.52; HNL 6.04; FL 12.22; NED 2.37; IND 1.92.

Coloration in life was recorded as follows (Fig. 10 ): Dorsal and lateral ground color of head and body Drab-Gray (256) with indistinct Raw Umber (280) blotches and mottling; dorsal surfaces of forelimbs True Cinnamon (260) with Raw Umber (280) speckles; dorsal surfaces of hind limbs Drab-Gray (256) with Raw Umber (280) transverse broken bars; a Drab-Gray (256) oblique bar from anterior corner of eye to snout; throat region heavily suffused with Vandyke Brown (282); venter Pale Neutral Gray (296) with Smoky White (261) stipples; ventral surfaces of forelimbs Medium Fawn Color (257); ventral surfaces of hind limbs Cream White (52); iris Olive Brown (278) with a suffusion of Orange-Rufous (56) above and whitish below.

Coloration after about three years preservation in 70% ethanol was recorded as follows: Dorsal and lateral ground color of head and body Glaucous (272) with indistinct Sepia (279) blotches and mottling; dorsal surfaces of hind limbs Glaucous (272) with Sepia (279) transverse broken bars; a Drab-Gray (256) oblique bar from anterior corner of eye to snout; supraocular region Dusky Brown (285); throat region Glaucous (289) with Pale Buff (1) stipples; venter Pale Buff (1) with Smoky White (261) stipples; ventral surfaces of forelimbs Glaucous (289); ventral surfaces of hind limbs Light Buff (2).

Variation.

The paratypes agree well with the holotype in general appearance; morphometrics and coloration (see Table 3 ).

Etymology.

“Myan” is Myanmar’s abbreviated name and was chosen because this species is endemic to Myanmar as far as we know. “hessei” was chosen in recognition of the long-term support and funding of Senckenberg by the German State of Hesse. In combination, the species name Phrynoglossus myanhessei reflects the long-term productive collaboration of researchers from Hesse and Myanmar in the field of herpetology.

Natural history notes.

At the type locality, the specimens were collected at night in a patch of muddy grass area, partly open, partly covered by bushes and low trees. The frogs were sitting at the edge of small shallow temporary water bodies.

Geographic Distribution and Conservation.

As currently known, Phrynoglossus myanhessei is restricted to central and lower Myanmar (Fig. 11 ). This species was abundant wherever we found it. Thus, we classify it as Least Concern according to the IUCN categories (IUCN, 2012).

Genomic characterization.

Whole genome sequencing and assembly: Illumina sequencing yielded 616,151,068 short-reads with a data amount of 92.4 Gb. K-mer analysis estimated the genome size to 2.6 Gb and heterozygosity 0.9%. The mitochondrial genome was assembled into one circular sequence with a length of 18,348 bp (accession number MW405414). All expected 13 protein coding genes, 2 rRNAs, 23 tRNAs, one D-loop region and the origin of replication could be annotated on the mitochondrial genome sequence. A pairwise alignment to the complete mitochondrial genome of Phrynoglossus martensii (GU177877) shows 77.1% pairwise identity. The final nuclear genome assembly contains 1,446,664 contigs with a total length of 1,829,122,027, an N50 of 1,468 and a GC of 41.07%. The backmapping rate is as high as 98.9% and after filtering, the genome sequence coverage of the holotype specimen is uniformly distributed at 25 ×. The BUSCO search resulted in 20.8% present BUSCOs (C:8.5%[S:8.4%,D:0.1%],F:12.3%,M:79.2%,n:5310) and no contamination could be identified by interpreting the blobplot. Raw reads and the draft-genome assemblies can be found within the BioProject PRJNA687006. For further details see Appendix 3.

Figures

Figure 8. Holotype of Phrynoglossus myanhessei n. sp. (SMF 103841). Scale bars equal 10.0 mm (A, B) and 5 mm (C-F). Photos by G. K.

Figure 9. Holotype of Phrynoglossus myanhessei sp. n. (SMF 103841). Scale bars equal 5.0 mm. Photos by G. K.

Figure 10. Phrynoglossus myanhessei sp. n. in life. (A) Male holotype, SMF 103841; (B) male paratype, SMF 103840; (C) male paratype, SMF 103799; (D) female paratype, SMF 103798. Photos by G. K.

Figure 11. Map indicating collecting localities of the Phrynoglossus species occurring in Indochina. Each symbol can represent one or more adjacent localities. Black squares: P. myanhessei n. sp.; black circles: P. martensii; green pentagons: P. cf. martensii; black triangles: P. magnapustulosus; white circles: additional specimens of Phrynoglossus from the FMNH, not examined by authors.