Fei's Small Tree Frog; Fei Shi Xiao Shu Wa (Chinese)

Liuixalus feii is a frog with a snout-vent length of 16.2 - 17.6 mm for males and 18.0 - 18.7mm for females. In dorsal view, the snout projects beyond the lower jaw. The canthus rostralis is rounded and apparent, and its interorbital region is flat. The loreal region is concave. The nostrils are oval, marginally arched, and closer to eye than to tip of snout. The internasal distance is slightly wider than the interorbital distance. The tympanum is distinct and half the size of the eye. The tympanic rim is barely elevated skin of temporal region. The supratympanic folds are noticeable, considerably curved, and extend from behind the eye to shoulder (Yang et al. 2015).The forelimbs are fairly robust with the relative fingers length being I < II < IV < III. The tips of fingers II, III, IV have well developed disks with obvious circummarginal grooves. The disks are wider than expected, relative to finger width, with the disk of finger III being 216% wider than the width of finger III and 68.4% of tympanum diameter. The tip of finger I is round and without a distinct disk. The fingers are free of webbing. The subarticular tubercles look outstandingly rounded with fingers I and II each having one and fingers III and IV having two. The outer palmar tubercle is divided in two and accessory palmar tubercles are blurred (Yang et al. 2015).The hindlimbs are long and slim about 171% of snout-vent length. The tibiotarsal articulation reaches the naris when adpressed along the body. The tibia length is 54% of snout-vent length. Relative lengths of toes are as follows: I < II < V < III < IV. The tips of toes have underdeveloped disks, with obvious circummarginal grooves, that are smaller than fingers. The subarticular tubercles are particularly rounded with toes I and II each having one, toes III and V each having two, and finger IV having three. The inner metatarsal tubercle is low, oblong, recognizable, and approximately 0.8mm in length. The outer metatarsal tubercle is very small and blurred (Yang et al. 2015).The dorsal surface of the head and body are shiny with fine granules, which are fairly prominent on flanks and eyelids. An indistinct longitudinal median ridge is present on dorsum. On the dorsal surface of the body and thighs, there are weak skin. The ventral surface of thighs and abdomen have flat granules but throat is smooth (Yang et al. 2015).Liuixalus calcarius differs from L. feii by L. feii having its nostrils closer to eyes than to tip of snout, the tibiotarsal articulation reaching the naris, toe V being shorter than toe III, and the males’s throat being dull white. Second, the features of L. feii are different from L. hainanus by male L. feii having a relatively smaller tympanum, shorter hindlimbs (specifically the tibias), tibiotarsal articulation reaches the naris when adpressed to the body, but reaches beyond the tip of snout in L. hainanus. The two species are further differentiated by L. feii’s lack of beige speckles on the dorsum and clear difference in eye color pattern; where L. feii has a bicolor iris, but L. hainanus has a yellowish iris with small dark spots above and below pupil. Liuixalus feii and L. ocellatus are differentiated by L. feii having a shorter snout and a normal sized tip of finger I that lacks a disk. Additionally, L. feii males have a smaller tympanum but longer hindlimbs than L. ocellatus. Last but not least, L. feii differs from L. romeri by having, in males, a relatively smaller tympanum, a snout that is longer than eye diameter. Additionally, in L. romeri, the tibiotarsal articulation reaches the mouth when adpressed and the fingers and toes are weakly webbed (Yang et al. 2015).In preservative, the dorsal surface is pale brown. Behind the eyes there is a dark X-shaped marking, consisting of two curved dark lines along the body that don’t contact in the middle. There is a dark interorbital bar between the eyes spreading to the upper eyelids, and on dorsal surface, dark transverse bars are present on the fore and hind limbs: two on the lower arm, three on the tibia, and four on the thigh. Moreover, on chest and venter, there are a few scattered, erratic dark spots. The ventral surface appears to be dirty white. The side of the head is dark brown and supratympanic fold is especially darker. In addition, the lower lip shows distinct dark bars and is pale white. There is a noticeable dark blotch on the anterior portion of shoulder joint. The iris is bicolored, with the upper third being pale white and lower two-thirds being dark brown (Yang et al. 2015).The six paratypes match with the overall characters of the holotype. All type specimens had two crooked dark lines and a dark X-shaped marking on dorsum. There are no symbolic differences between males and females, but females are barely larger than males, which is the snout-vent length 18.0 mm and 18.7 mm versus 16.2 mm and 17.6 mm (Yang et al. 2015).The species authority is: Yang, J.H., Rao, D.Q., Wang, Y.Y. (2015). A new species of the genus Liuixalus (Anura: Rhacophoridae) from southern China. Zootaxa 3990(2): 247-258Based on Bayesian Inference and Maximum Likelihood analysis derived from a partial sequence of the mitochondrial 16s rRNA gene region, L. feii is sister to the clade containing L. calcarius and L. catbaensis. The next most closely related species is L. romeri (Yang et al. 2015). The specific name, “feii”, refers to the name of Professor Liang Fei of the Chengdu Institute of Biology, in recognition of his long-term work and his contribution to the advancement of amphibian research in China (Yang et al. 2015).

Liuixalus feii is currently known from Heishiding Nature Reserve, Fengkai County, Guangdong Province, China. Almost all specimens were founded on leaf-litter on the forest floor in a protected primary forest at elevations between 350 – 800 m (Yang et al. 2015).

Liuixalus feii have been heard calling between April and October. On 2 May 2010, eight free-swimming tadpoles and one adult male were found in a small hole in the roots of a large tree, about 10 cm above the ground and containing water, 2 cm deep. All other specimens were found away from steams or pools, on the forest floor. In addition, no individuals were spotted along rivers, ponds, or wetlands, indicating this is a more terrestrial species. The new species appears to be a forest-dependent species, and is perhaps a phytotelm-breeder, breeding in bamboo holes in the forest or water accumulated in tree (Yang et al. 2015).