Hynobius guabangshanensis Shen, Deng & Wang, 2004
Conservation data are deficient for this species because it is only known from the type locality in central Hunan, China. At its type locality, as few as around 100 females reproduced each year from 2003 to 2006 in 5 sites; there were 11 sites in 2002 (Guo et al., 2008). The range could be less than 10 km2.
The interior line of vomerine teeth reaches posterior margin of eye. Angle of jaw far exceeds the posterior margin of eye. When limbs are adpressed, fingers and toes overlap for a length of two costal grooves. Tubercles present on palms and soles. 13 costal grooves. Tail relatively short, only about 70% of the snout-vent length. Venter has small white speckles (Shen et al., 2004).
Karyotype:
2n=56, 1M, 2SM, 3SM, 4ST, 5SM, 6M, 7SM, 8SM, 9SM, 10M/SM, 11SM, 12SM, 13M, 14M, 15M, 16M, 17M, 18M, m (19–28), from Xiong et al. (2008).
M: metacentric; SM: submetacentric; T: telocentric; ST: subtelocentric; m: micro-chromosome
The mitochondrial DNA has been sequenced by Nishikawa et al. (2010).
Summarized from Shen et al. (2004). This salamander looks like Hynobius amjiensis but differs from the latter by a smaller body size (total length 140 mm vs. 160 mm), a more slender vomerine teeth patch with more teeth (34–38 vs. 19–24), a shorter tail (proportion to snout-vent length: 70% vs. 90%) and shorter egg sacs (less than 200 mm vs. more than 300 mm).
Summarized from Shen et al. (2004). A moderate-sized salamander (total length 125–151 mm). Head is oval-shaped. Snout is rounded. Bulging eyes are retractable. Iris is golden in life. Labial fold absent. Gular fold is prominent and visible in dorsal view. Angle of mouth far exceeds the posterior margin of eye. A vertical groove crosses over a horizontal groove posterior to the eye. Vomerine teeth are aligned in V-shape or U-shape. The interior line of vomerine teeth reaches the posterior margin of eye. Body is stout. Vertebral groove present. 13 costal grooves. Limbs are well-developed. When limbs are adpressed, fingers and toes overlap. Tubercles present on palms and soles. The base of tail is rounded, and the posterior part becomes laterally compressed. Dorsal caudal fin starts from tail base and ventral caudal fin starts from middle part of the tail. In breeding season, males have a swollen cloaca with a light-colored papilla followed by a longitudinal groove. The vent of females is a non-swollen longitudinal groove. In life, dorsal color is dark black and turns a little yellowish green under the sun. Ventral color is light grey with small white speckles.
All measurements are from Shen et al. (2004).
Male (1 specimen, type). Total length: 146.3 mm; snout-vent length: 85.2 mm; Head length: 21.6 mm; Head width: 18 mm; forelimb length: 26.1 mm; hind-limb length: 28 mm.
Female (8 specimens). Total length: 125.4–151 mm; snout-vent length: 72.8–87.5 mm; Head length: 18.5–21.6 mm; Head width: 14.3–18.8 mm; forelimb length: 23.8–26.7 mm; hind-limb length: 25–27.7 mm.
Based on mitochondrial DNA data, Hynobius guabangshanensis is the sister taxon to the group of H. chinensis and H. maoershanensis (Nishikawa et al., 2010).
Only known from near Guabangshan Forest Station (the middle part of the Qi Mountains), Qiyang Hynobius Nature Reserve, central Hunan, China.
The forest station is located in a hilly landscape with elevations from 140 to 800 m. Hills are covered with firs and bamboo forest. Below 400 m are rice paddies. There are small ponds or swamps, which are breeding sites for Hynobius guabangshanensis. Outside the breeding season, it is found under fallen leaves or soft soil. Local people occasionally dig them out in crop fields (Shen et al., 2004). They are most active during the night (Guo et al., 2008).
Summarized from Guo et al. (2008). The breeding season is from November to January. Adults gather in small shallow ponds or temporary puddles (sometimes in rice paddies), hide in crevices or among aquatic plants and crawl out during night. Males gather around plants or underwater twigs, and females wander around. From 2003 to 2006, around 100 females reproduced each year. Eggs were mostly laid from 5 pm to midnight. The shape of the egg sac resembles a banana. It is attached to aquatic plants or twigs with one end; the other end is free. The egg sac absorbs water and grows in length during the development of embryos. When larvae hatch, the length of the egg sac reaches around 180 mm. Each egg sac contains around 90 eggs, each of which is 2 mm in diameter.
The male courtship display starts when a female approaches. The male grasps an aquatic plant, arches its body in C-shape and shakes every 2 to 20 seconds. The female attaches a pair of egg sacs to the plant. She pulls the egg sacs out with her hind legs. Then the male grasps the female and egg sacs and ejects sperm with its mouth wide open. Both animals wiggle and bend. After the eggs are fertilized, the female swims away. The whole process lasts for 16 and 26 minutes (two observations). The male stays and guards the egg sacs from attack by other males by shaking, opening his mouth widely and biting. Females leave the pond in 12–48 hours; males stay on for up to a month.