Alpheus millsae Anker, Hurt and Knowlton, 2007
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| Original Description | Alpheus millsae Anker, Hurt and Knowlton, 2007a: 50, figs. 3, 4, 5c, 6c, 7g-m, 8c. |
| Classification | Arthropoda: Crustacea: Malacostraca: Decapoda: Alpheidae. |
| Synonymy | Alpheus canalis sp-b (blue) in Knowlton and Mills, 1992. |
| Type Locality | Panama City, Panama (symbol  on the map). |
| Type Material | Holotype: USNM 1100686, in ethanol and excellent condition. Paratypes in MNHN, RMNH, UP and USNM. |
| Common Name | Mills' snapping shrimp. |
| Taxonomic Status | Valid. |
| Geographic Distribution | Tropical eastern Pacific [EP]: presently known only from a few localities in Panama (see map). |
| Frequency | Local and relatively uncommon. This species was collected off Casco Viejo and along Amador causeway. |
| Habitat | Rocky or mixed sand-rock bottoms, under stones. |
| Depth Range | Lower intertidal (extreme low tide mark) to upper subtidal, about 15-20 m. |
| Life History and Behavior | Lives in pairs, sometimes in company of fireworms (Amphinomidae). |
| Related Species | Alpheus galapagensis Sivertsen, 1933 [EP]; A. nuttingi (Schmitt, 1924) [WA]. Alpheus millsae can be distinguished from the sympatric A. galapagensis by the absence of spine on the ischium of the third pereiopod (present in A. galapagensis) and by the pale blue antennal and antennular flagella (pale orange in A. galapagensis); and from it's transisthmian sister species, A. nuttingi, by the posteriorly more extending rostral carina; the presence of three small dark spots, two dorsolateral on the third abdominal somite and one mediodorsal on the fifth abdominal somite (these spots are usually absent or feebly marked in A. nuttingi); and the predominantly non-interconnected pale dots (mostly interconnected, sometimes forming chains or reticulated areas, in A. nuttingi). |
| Size | Body length to about 40 mm. |
| Color Pattern | See photo. |
| Molecular Barcode | GenBank number EF092283. |
| Remarks | Alpheus millsae occurs in somewhat deeper water (lower intertidal and subtidal) compared to A. galapagensis and is therefore more rarely collected. |
| Major References | Knowlton and Mills, 1992 [recognition of three cryptic species on the basis of color pattern]; Knowlton et al., 1993 [recogniton of three cryptic species based on molecular studies]; Anker, Hurt and Knowlton, 2007a. [original description and illustrations, color photos, revision of A. nuttingi species complex]. |