Holthuis, 1946
Diagnosis:
Carapace with 2 distinct teeth in the median line before the cervical groove (the gastric and rostral teeth), the pregastric tooth is absent. The region between the postrostral and branchial carinae with only a few tubercles and extensive smooth areas. Abdominal somites 2 to 5 with distinct elevated median longitudinal carina; the carina of the third somite is distinctly higher than that of the other somites. The exposed part of the somites without arborescent pattern, but with a wide transverse groove over the middle; behind this groove a transverse ridge extends along the posterior margin of the somite; before the groove there are tubercles and some wide side grooves. Somite 1 dorsally smooth with only an indication of a transverse groove in the extreme lateral part. Posterior margin of somites 5 and 6 not tuberculate. Fourth segment of antenna with the median oblique carina distinct but not quite straight; a row of tubercles is present on the outer half of the upper surface of the segment, tubercles are also present in the basal part of the median carina. The outer margin of the fourth segment has 3 or 4 teeth, the distal largest, the inner margin with 4 or 5 teeth, the basal of which is largest (the apical tooth not included in these counts). The thoracic sternum is widely U-shapedly incised anteriorly; the last 4 sternites show an inconspicuous median tubercle. A dorsal fringe of hairs is present on the dactyli of pereiopods 3 to 5.
Colour: dark brown above, tubercles slightly paler, sometimes with whitish areas in the branchial region and along the central part of the cervical groove. A dark blue spot in the median part of the first abdominal somite (see Chan and Yu, 1986, pl. 5, 9 fig. C, D).
Type:
Type locality: "southern Bungo Strait [between Shikoku and Kyushu Islands, Japan), 110 m deep". Holo-type male in Fishery Institute, College of Agriculture, Tokyo University, Tokyo, Japan (dried and in poor condition). As S. brevicornis is a new name for A. rugosus, the type locality is the same for both.
Diagnostic Features:
Carapace with 2 distinct teeth in the median line before the cervical groove (the gastric and rostral teeth), the pregastric tooth is absent. The region between the postrostral and branchial carinae with only a few tubercles and extensive smooth areas. Abdominal somites 2 to 5 with distinct elevated median longitudinal carina; the carina of the third somite is distinctly higher than that of the other somites. The exposed part of the somites without arborescent pattern, but with a wide transverse groove over the middle; behind this groove a transverse ridge extends along the posterior margin of the somite; before the groove there are tubercles and some wide side grooves. Somite 1 dorsally smooth with only an indication of a transverse groove in the extreme lateral part. Posterior margin of somites 5 and 6 not tuberculate. Fourth segment of antenna with the median oblique carina distinct but not quite straight; a row of tubercles is present on the outer half of the upper surface of the segment, tubercles are also present in the basal part of the median carina. The outer margin of the fourth segment has 3 or 4 teeth, the distal largest, the inner margin with 4 or 5 teeth, the basal of which is largest (the apical tooth not included in these counts). The thoracic sternum is widely U-shapedly incised anteriorly; the last 4 sternites show an inconspicuous median tubercle. A dorsal fringe of hairs is present on the dactyli of pereiopods 3 to 5. Colour: dark brown above, tubercles slightly paler, sometimes with whitish areas in the branchial region and along the central part of the cervical groove. A dark blue spot in the median part of the first abdominal somite (see Chan and Yu, 1986, pl. 5, 9 fig. C, D).
Geographical Distribution:
East China Sea (west of the Tokara Islands), Japan (Tosa Bay, Bungo Strait), Taiwan.
Habitat and Biology:
Depth range from 60 to 150 m; substrates: sand or mud.
Size:
Total body length 4 to 5.5 cm. Carapace length of 1.3 to 1.8 cm; in ovigerous females 1.6 to 1.8 cm.
Interest to Fisheries:
None so far as known. The specimens enter trawls by accident and then are found at fish markets, more likely as trash than as saleable products. Chan and Yu (1986:149) reported the species from local fish markets in Taiwan, these specimens were taken by "baby" shrimp trawlers.