Alpheus millsae Anker, Hurt, and Knowlton 2007
Alpheus millsae is an eastern Pacific snapping shrimp, and occurs under rocks on coarse sand. As of 2010, it was only known from areas around Panama city, Pacific Panama. For more details, see http://biogeodb.stri.si.edu/bioinformatics/alpheus/Alpheus_Template.php?....
Alpheus millsae belongs to the Edwardsii species group within the genus Alpheus (Anker et al. 2007). The species is named after DeEtta K. Mills. Type locality: Panama City, Pacific Panama (Anker et al. 2007), types stored at the National Museum of Natural History, Smithsonian Institution (USNM). Holotype: USNM 1100686.
A. millsae appears to be ecologically similar to A. galapagensis, but tends to occur in deeper water (low intertidal to shallow subtidal), occurring under rocks on coarse sand; some individuals were found together with fireworms (Amphinomidae)(Anker et al. 2007).
Maximum body size (carapace length, or CL) of males is 13.7 mm (holotype); females, 12 mm (Anker et al. 2007). Color: Body greenish or greenish-brown, speckled with numerous pale yellow dots; dactylus of major chela (claw) distally pink and white; antennae area blue or bluish-green; ovigerous females with olive-green eggs (Anker et al. 2007). Alpheus millsae can be differentiated from the sympatric and closely related A. galapagensis by the absence of spine on the ischium of the third pereiopod, and by the pale blue antennal region (which is pale orange in A. galapagensis. A. millsae can be differentiated from its transisthmian sister species (A. nuttingi) by the posteriorly more extending rostral carina and by color patterns (see Anker et al. 2007, Knowlton et al. 2008 for more details).
Alpheus canalis sp. b (Knowlton and Mills, 1992, Knowlton et al. 1993); Alpheus canalis "blue" (Williams et al. 2001).
Snapping shrimp in the genus Alpheus have been a model system for studying molecular divergence in "transisthmian" taxa that diverged following the closure of the Isthmus of Panama. Alpheus millsae occurs in the eastern Pacific, and is morphologically and genetically similar to Alpheus nuttingi from the West Atlantic (Anker et al. 2007); estimates of divergence based on genetic sequence variation suggest that this transisthmian species pair was isolated ~ 7 mya (Hurt et al. 2009).
Sequenced in Knowlton et al. 1993, Williams et al. 2001, Hurt et al. 2009; sequences available in GenBank for COI (AF309881-2, FJ013877-80), elongation-factor 2 (FJ013582-87), elongation-factor 1 alpha (FJ013532-7), glucose-6-phosphate isomerase (FJ013775-80), tetrahydrofolate synthase (FJ013846-48), putative GTP-binding protein (FJ013683-88), and alanyl-tRNA synthetase (FJ013374-80).
Eastern Pacific: Casco Viejo (Panama City) and Rio Mar, Panama (Anker et al. 2007).