Corresponding author: Shane T. Ahyong (
Academic editor: S. De Grave
Four species of freshwater crabs from three genera and two families (
Huang C, Wong KC, Ahyong ST (2018) The freshwater crabs of Macau, with the description of a new species of
Best known as the gambling capital of the world, Macau (also known as Macao) has a total land area of only 30.8 km2 but a population of more than 650,000 people, making it one of the most densely populated regions in the world (Government of Macao Special Administrative Region Statistics and Census Service). Macau historically consists of the Macau Peninsula (bordered by Zhuhai to the north) and two islands: Taipa and Coloane. The two islands are now joined by Cotai, an area created by land reclamation in 2005.
The freshwater crabs of Macau have not been scientifically documented to the best of our knowledge. General wetland faunal surveys from 2007 onwards have found freshwater crabs in Coloane resulting in a small collection kept in the Macao Civic and Municipal Affairs Bureau. Upon examination, it was found that these freshwater crab specimens contained three species,
Localities of the sampling sites in and around Macau.
Specimens were collected by hand and preserved in 75% ethanol from 2007 onwards from South China. They are deposited in the Sun Yat-sen Museum of Biology,
The terminology used primarily follows that of
Holotype:
The freshwater crabs of Macau, colour in life.
China:
Hengqin Island, Zhuhai, Guangdong; Coloane, Macau.
Holotype:
Macau:
Carapace broader than long, regions indistinct, dorsal surface convex, anterolateral region weakly rugose (Figs
Carapace broader than long, width about 1.2 × length (n = 6); regions indistinct, dorsal surface convex; surface generally smooth, pitted, anterolateral region weakly rugose (Figs
Maxilliped III merus about as wide as long; ischium width about 0.7 × length; merus subtrapezoidal, with median depression; ischium subtrapezoidal, with distinct median sulcus, mesial margin rounded. Exopod reaching to proximal one-third of merus; flagellum short (Fig.
Chelipeds (pereiopod I) unequal (Figs
Ambulatory legs (pereiopods II–V) slender, setae short, very sparse (Figs
Male thoracic sternum generally smooth; sternites I–IV narrow, width about 1.5 × length; sternites I, II forming triangular structure; sternites II, III fused, but demarcated by shallow transverse sulcus; sternites III, IV fused, demarcation inconspicuous (Fig.
Male pleon triangular; somites III–VI progressively narrower, lateral margins almost straight; somite VI width 1.8–2.1 × length (n = 6); telson width 1.3–1.4 × length (n = 6); apex rounded (Fig.
This species is named after the type locality, Macau; used as a noun in apposition.
Variable, carapace and ambulatory legs dark brown to purple; chelipeds a combination of brown, orange and white (Fig.
Coloane, Macau.
As with many other species of
Comparison of
Holotype: AS-CB 05141, male (33.2 × 26.4 mm), Guangdong Province, China, gift from Sun Yat-Sen Medical College, no date [photographs examined].
SYSU 001001, male (38.5 × 30.0 mm), Xiangzhou (
Highly variable, even within the same population. Carapace and ambulatory legs dark brown to purple; chelipeds a combination of brown, orange and white (Fig.
Guangdong: Zhuhai, Zhongshan, Jiangmen; Macau: Taipa.
Little was previously known about
Normal and blue coloured
The
Neotype: JX 050563, male (22.4 × 18.3 mm), Xiaba (
JX 050564, JX 050566, JX 050568–050569, 4 males (16.2 × 13.2 mm, 15.5 × 12.6 mm, 13.0 × 10.9 mm, 14.0 × 11.5 mm), same data as neotype. JX 050565, JX 050567, JX 050570–050576, 9 females (16.1 × 13.2 mm, 13.0 × 10.5 mm, 25.3 × 20.8 mm, 23.4 × 19.5 mm, 24.9 × 20.3 mm, 21.6 × 17.6 mm, 16.9 × 13.7 mm, 14.8 × 11.7 mm, 15.2 × 12.4 mm), same data as neotype.
Carapace broader than long, width about 1.2 × length (n = 14); regions indistinct, dorsal surface convex; surface generally smooth, pitted, anterolateral region slightly rugose (Fig.
Maxilliped III merus about as wide as long; ischium width about 0.7 × length; merus subtrapezoidal, with median depression; ischium subtrapezoidal, with distinct median sulcus, mesial margin rounded. Exopod reaching to proximal one-third of merus; flagellum short.
Chelipeds (pereiopod I) unequal (Fig.
Ambulatory legs (pereiopods II–V) slender, setae short, very sparse (Fig.
Male thoracic sternum generally smooth; anterior thoracic sternum (sternites I–IV) narrow, width about 1.5 × length; sternites I, II forming triangular structure; demarcation between sternites II, III complete; sternites III, IV fused with vestigial median suture (Fig.
Male pleon triangular, lateral margins almost straight; somites III–VI progressively narrower; somite VI width 2.1–2.2 × length (n=2); telson width 1.2–1.3 × length (n=2); apex rounded (Fig.
Currently only known from Xiaba, Wuping County, Longyan City, Fujian.
The original description of
Generally brown overall; larger individuals may have dark markings near the cardiac region (Fig.
Coloane, Macau; Guangdong: Guangzhou City, Shenzhen City, Zhuhai City, Sihui City, Shaoguan City, Shanwei City, Heyuan City, Chaozhou City; Zhejiang: Wenzhou City.
Comparison of
This project was partly funded by the PANGEA research centre student grants program (UNSW) to the first author. Special thanks are expressed to XM Zhou, JX Zou, and their students (Nanchang University) for assisting the first author in examining specimens at Nanchang University, and to ZC Zhou for his donations of several