Pleistacantha

Ahyong, Shane T., Chen, Huilian & Ng, Peter K. L., 2005, Pleistacantha stilipes, a new species of spider crab from the South China Sea (Decapoda: Brachyura: Majidae)., Zootaxa 822, pp. 1-10 : 7-8

Key to species of Pleistacantha

1 Interantennular spine simple ......................................................................................... 2

­ Interantennular spine distally bifid................................................................................ 4

2 Carapace granular with about 9 longer spines and spinules. Rostral spines with only 1 or 2 accessory spines near base ........................................................................ P. naresii

­ Carapace and legs densely covered by long spines and spinules. Rostral spines each with at least 4 long accessory spines along their length................................................ 3

3 Rostral spines at least one­third postrostral carapace length, clearly exceeding interantennular spine ............................................................................................ P. cervicornis

­ Rostral spines shorter than one­quarter postrostral carapace length, subequal to interantennular spine .................................................................................... P. exophthalmus

4 Rostral spines adjacent or appressed in proximal half to three­quarters. Carapace spinulous, with a few prominent spines dorsally and on anterior and posterior branchial margins ................................................................................................................. 5

­ Rostral spines separate and divergent from base. Carapace spinulous, with or without prominent dorsal spines; without prominent spines anterior and posterior branchial margins..........................................................................................................................6

5 Pereopod 5 merus distinctly longer than postrostral carapace length (1.3–1.4 males; 1.3 female). Cheliped propodus not distinctly inflated in males ...................... P. stilipes

­ Pereopod 5 merus not markedly longer than postrostral carapace length (1.2 in males; subequal in females). Cheliped propodus distinctly inflated in males. P. sanctijohannis

6 Rostral spines short, about one­quarter postrostral carapace length, with four or fewer accessory spines including those at base....................................................................... 7

­ Rostral spines at least one­third postrostral carapace length, with 9–12 accessory spines including those at base ....................................................................................... 8

7 Interantennular spine bifid almost from base, not more than twice as long as distal width. Rostrum with accessory spines only at base. Carapace surface with sharp tubercles or short spines, but no prominent spines .................................................. P. simplex

­ Interantennular spine bifid at tip, four or more times as long as distal width. Rostrum with accessory spines beyond base. Carapace surface spinulous with a few more prominent spines ........................................................................................... P. japonica

8 Interantennular spine bifid for no more than distal third. Spines on carapace including several prominent spines on gastric, cardiac and branchial region ...................... P.oryx

­ Interantennular spine bifid for at least distal half. Spines on carapace of uniform length ....................................................................................................................... P. moseleyi