E-Fauna BC Home

Calastacus stilirostris Faxon, 1893
Mud Shrimp
Family: Axiidae

Photograph

Once images have been obtained, photographs of this taxon will be displayed in this window.Click on the image to enter our photo gallery.
No E-Fauna image is available for this taxon.

Map

E-Fauna BC Static Map

Distribution of Calastacus stilirostris in British Columbia in British Columbia

Species Information

Carapace surface smooth. Rostrum long and narrow with stout teeth at base. A narrow ridge on anterior dorsal area. Eyestalk short with unpigmented globular cornea. Peduncle of antenna with long narrow projections or “thorns” on 2nd and 3rd segments and a long setose flagellum. Chelipeds large, subequal and with sharp marginal teeth, some spines on inner surface of palm and no gape between fingers, the tips of which are crossed. Walking legs slender, with smooth surfaces and setose, 1st shorter than others and chelate with fine spines on cutting surfaces. Abdomen relatively slender with well developed pleura with lateral margins slightly angled. Tail fan with telson subequal in length to uropods and much longer than 6th abdominal segment. Telson elongate rectangular with 2 unarmed ridges. Uropods with unarmed ridges and outer margins with teeth. Hermaphrodites, so gonopores on coxae of 3rd and 5th pereiopods (2nd and 4th walking legs). Pleopods on 1st abdominal segment, uniramous and modified for copulation. 2nd to 5th pleopods biramous, slender and with appendix interna and long setae, paricularly on base where bits of egg membrane may still be attatched.

Size

Carapace: 22 mm. Total length: 52 mm.

Colour

Unrecorded.

Biology

Family Description

The thin-shelled shrimp-like animals in this family are all burrowers and are found from shallow subtidal habitats to great depths. Recently Pemberton, Risk and Buckley (1976) determined that one species found off Nova Scotia makes burrows more than 2.5 m into the substrate. Obviously in abyssal regions the collection of these animals under such circumstances in particularly haphazard. Thus the number of specimens obtained is few and often these are damaged. Four species of this family are known to occur in the waters off British Columbia. All have one or two small hollow knobs of apparently unknown function on the mid-dorsal ridge of the carapace. These species have been assigned to the genera Axiopsis, Calastacus and Calocaris. The definitions of these genera were made when few species had been studied and recent discoveries indicate that the criteria used are not satisfactory. New genera will have to be created and the taxonomy of the Family revised. It is important that any specimens obtained should be carefully preserved and placed in suitable research collections where they will be available for future study.

Habitat


Brown sand or rock.

Distribution

Range

From southwestern British Columbia to Peru (16°S, 73°27’W); 700 to 1208 m.
Distribution In British Columbia

One record: September 1964, southwest of Vancouver Island (47°58’N, 125°47.2’W); from 924 m.

Status Information

Origin StatusProvincial StatusBC List
(Red Blue List)
COSEWIC
UnlistedUnlistedUnlistedUnlisted



BC Ministry of Environment: BC Species and Ecosystems Explorer--the authoritative source for conservation information in British Columbia.

General References