Alpheus arenensis (Chace, 1937)
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| Original Description | Crangon arenensis Chace, 1937: 119, fig. 4. |
| Classification | Arthropoda: Crustacea: Malacostraca: Decapoda: Alpheidae. |
| Synonymy | Alpheus websteri sensu Wicksten, 1983 and Kim and Abele, 1988. |
| Type Locality | Arena Bank, S Baja California, Mexico (symbol  on the map). |
| Type Material | USNM 0000000, in ethanol, in fairly good condition. |
| Common Name | Arena snapping shrimp. |
| Taxonomic Status | Valid. Wicksten (1983) and Kim and Abele (1988) treated A. arenensis as a junior synonym of A. websteri. Taxonomic status revision by Anker, Hurt and Knowlton, 2008a. |
| Geographic Distribution | Tropical and subtropical eastern Pacific [EP]: from S Gulf of California to Colombia and Galapagos (see map). |
| Frequency | Relatively uncommon throughout its range. |
| Habitat | Hard and mixed soft-hard bottoms with sand, corals, coral rubble and rocks; in crevices of coral rocks or coral bases. |
| Depth Range | Intertidal and shallow subtidal, probably to about 20 m. |
| Life History and Behavior | Lives in pairs in rock or coral crevices. |
| Related Species | Alpheus websteri Kingsley, 1880 [WA]; A. fagei Crosnier and Forest, 1965 [EA]; more distantly: A. rugimanus A. Milne Edwards, 1878 [EA]; more distantly: A. thomasi Hendrix and Gore, 1973 [WA]. Alpheus arenensis differs only slightly from A. websteri and A. fagei, e.g., from A. websteri by the much smaller tooth on the merus of the major cheliped (see Kim and Abele, 1988); from A. fagei by the relatively longer ventrolateral tooth of the antennal basicerite (see Crosnier and Forest, 1966); and from both species by its color pattern (see comparison photos). Alpheus arenensis can be easily separated from A. rugimanus by the much shorter ventrolateral tooth of the antennal basicerite; from A. thomasi by the shorter rostrum and more robust minor cheliped; and from both A. rugimanus and A. thomasi by a clearly different color pattern (see comparison photos). |
| Size | Body length to about 22 mm. |
| Color Pattern | See photo. |
| Molecular Barcode | GenBank number EU339466. |
| Remarks | |
| Major References | Chace, 1937 [original description, as Crangon arenensis]; Wicksten, 1983 [premature synonymy conclusions, records in Gulf of Mexico, as A. websteri]; Kim and Abele, 1988 [description of E Pacific material, illustrations, as A. websteri]; Villalobos, 2000 [records in Gulf of California, as A. websteri]; Williams et al., 2001 [confirmation of validity of two transisthmian species, position within Alpheus based on molecular data, as A. websteri]; Anker, Hurt and Knowlton, 2008a [precision of status, color photos, revision of A. websteri species complex]. |