Zhangixalus pachyproctus Yu, Hui, Hou, Wu, Rao & Yang, 2019

Materials

Type status: Other material. Occurrence: catalogNumber: LS. 2023.36; individualCount: 1; sex: male; occurrenceID: 43C1E6EB-F58E-5F5E-B999-9636D9DC169C; Taxon: scientificNameID: Zhangixalus pachyproctus; scientificName: Zhangixalus pachyproctus; class: Amphibia; order: Anura; family: Rhacophoridae; genus: Zhangixalus; specificEpithet: pachyproctus; scientificNameAuthorship: Yu, Hui, Hou, Wu, Rao, and Yang, 2019; Location: country: Vietnam; countryCode: VN; stateProvince: Lang Son; county: Lang Son; municipality: Bac Son; locality: Near Tran Yen Commune; verbatimElevation: 610; verbatimLatitude: 20°20'020"N; verbatimLongitude: 103°34'302"E; verbatimCoordinateSystem: WGS 84; Event: eventDate: May; eventTime: 2023; eventRemarks: collected by A. V. Pham; Record Level: language: en; collectionCode: Amphibia; basisOfRecord: PreservedSpecimen

Type status: Other material. Occurrence: catalogNumber: LS. 2023.45; individualCount: 1; sex: male; occurrenceID: 2B6B36F7-B099-54A1-A5E3-2F1A6FD4196E; Taxon: scientificNameID: Zhangixalus pachyproctus; scientificName: Zhangixalus pachyproctus; class: Amphibia; order: Anura; family: Rhacophoridae; genus: Zhangixalus; specificEpithet: pachyproctus; scientificNameAuthorship: Yu, Hui, Hou, Wu, Rao, and Yang, 2019; Location: country: Vietnam; countryCode: VN; stateProvince: Lang Son; county: Lang Son; municipality: Bac Son; locality: Near Tran Yen Commune; verbatimElevation: 610; verbatimLatitude: 20°20'020"N; verbatimLongitude: 103°34'302"E; verbatimCoordinateSystem: WGS 84; Event: eventDate: May; eventTime: 2023; eventRemarks: collected by A. V. Pham; Record Level: language: en; collectionCode: Amphibia; basisOfRecord: PreservedSpecimen

Description

Morphological characters of specimens from Vietnam agreed well with the description of Pham et al. (2017) and Yu et al. (2019): SVL min-max: 71.9–83.4 mm; mean and SD: 77.81 ± 2.66 mm, n = 37), MW 24.9–31.2 mm (27.29 ± 1.26 mm, n = 37) and body mass (BM 18.6–39.0 g, 29.49 ± 6.76 g, n = 37) in males was smaller than that in the female SVL 87.5 mm; MW 31.9 mm; BM 42.5 g. There was a significant relationship between SVL, MW and BM (SVL and HW: F 1, 41 = 7.085, P <0.001, R 2 = 0.733; SVL and BM: F 1, 41 = 13.408, P <0.001, R 2 = 0.825; and HW and BM: F 1, 41 = 2.272, P = 0.040, R 2 = 0.613 (Fig. 1). Snout round; loreal region sloping, slightly concave; nostril oval, slightly protuberant, closer to snout tip than to eye (SNL 4.2–4.4 mm, DNE: 5.0– 5.1 mm, n = 2, males); internarial distance narrower than interorbital distance and wider than upper eyelid width (IND 8.4–8.6 mm, IOD 9.2–9.5 mm, UEW 6.4–6.8 mm); tympanum distinct, round, more than half eye diameter (TD 4.8–5.2 mm, ED 7.3–7.7 mm) (Table 1); vomerine teeth present, in two series, touching inner front edges of choanae, separated from each other; tongue attached anteriorly, deeply notched posteriorly; internal single vocal sac present in males.

Forelimbs: FHL 38.3–38.5 mm; relative length of fingers I <II <IV <III; tips of all fingers expanded into discs with circum-marginal and transverse ventral grooves; nuptial pads present on first and second fingers; fingers webbed (Table 1).

Hind-limbs: Thigh shorter than tibia and foot (THL 35.9–36.4 mm, TL 36.9–37.1 mm, FL 36–36.6 mm); relative length of toes I <II <III <V <IV; tips of toes expanded into discs with circum-marginal and transverse ventral grooves; toes fully webbed; inner metatarsal tubercle distinct, oval; outer metatarsal tubercle absent; heels slightly overlapping when legs at right angle to body (Table 1).

Skin. Dorsal skin smooth; supratympanic fold distinct, curving from posterior edge of eye to insertion of arm; throat and chest smooth, flanks, belly and ventral surface of thighs granular; a narrow dermal fringe along outer edge of tarsus and fifth toe; vent protruding, forming an arc-shaped swelling.

Colouration in life. Dorsal surface green with some yellow dots; supratympanic fold and flanks light green; with a light stripe from the margin of the lower jaw to the groin; ventral surface of body and limbs grey white; lower part of flanks, abdomen and ventral surfaces of hind-limbs scattered with clouded light brown spots (Fig. 2). Colouration in preservative, see (Fig. 3) and (Fig. 4).

Ecology notes. This species was found on the ground or on tree branches, about 0.5–2.5 m above the forest floor, near ponds. Surrounding habitat was mixed evergreen forest of small hardwood, bamboo and shrub at elevations between 500 and 1110 m.

Distribution

In Vietnam, this species was recorded from Son La, Tuyen Quang, Bac Giang, Cao Bang, Quang Ninh and Nghe An Provinces (Pham et al. 2017, Frost 2024). Elsewhere, this species is known from China, Thailand and Laos (Frost 2024). This is a new record for Lang Son Province.

Diet

A total of 38 adult individuals (37 males and 1 female) of Z. pachyproctus was collected from Son La and Lang Son Provinces. We identified 681 prey items for sampled Z. pachyproctus, including 680 prey items in males and one prey item in the female.

The number of prey items per individual was 1–64 items (average 17.92 ± 16.58 items).

Mean prey item length was 3.41 ± 4.11 mm (ranging from 0.90 to 45.00 mm) and mean prey item width was 1.18 ± 1.06 mm (ranging from 0.60 to 12.00 mm) in both sexes. The average volume per individual was 245.38 ± 424.71 mm 3 (ranging from 0.26 to 1544.10 mm 3).

There was no positive correlation between the frog’s SVL, MW, BM and the prey volume per individual (SVL, Kendall’s tau b: tau = 0.107, P = 0.366; MW: tau = - 0.089, P = 0.467; BM: tau = 0.043, P = 0.714) (Fig. 5).

We identified 12 prey categories in the stomachs of Z. pachyproctus. Insects were the main food component of Z. pachyproctus, with nine categories and other invertebrates (Oligochaeta, Scolopendromorpha and Gastropoda) (Table 2).

The highest number of prey items found was Orthoptera (41.56 %), followed by Coleoptera (25.99 %), Mantodea (9.1 %), Blattodea (8.37 %), Hemiptera (7.05 %) and Hymenoptera (4.99 %). While the most frequently foraged prey group was Coleoptera (40.0 %), followed by Orthoptera (20.0 %), Blattodea (10.0 %) and Hemiptera (5.0 %). In terms of IRI, Coleoptera (24.52 %), followed by Orthoptera (24.43 %), Blattodea (9.12 %), Mantidae (8.14 %) and Hemiptera (4.05 %) were found (Fig. 6). The total dietary breadth of Z. pachyproctus from Vietnam was 0.89 (Simpson’s index of diversity) and Shannon’s evenness was 0.77.