Alpheus rostratus Kim and Abele, 1988

Alpheus rostratus
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Original DescriptionAlpheus rostratus Kim and Abele, 1988: 51, fig. 21. 
ClassificationArthropoda: Crustacea: Malacostraca: Decapoda: Alpheidae. 
Type LocalityTower Island, Galapagos (symbol on the map). 
Type MaterialUSNM 000000, in ethanol and good condition. 
Common NameBrown-clawed banded snapping shrimp. 
Taxonomic StatusValid. 
Geographic DistributionTropical eastern Pacific [EP]: from C Gulf of California to Colombia and Galapagos (see map). 
FrequencyFairly common. 
HabitatRock or sand-rock bottoms, also coral rubble. 
Depth RangeIntertidal and shallow subtidal to about 6 m. 
Life History and BehaviorFree-living, usually in pairs, under rocks and in rock/rubble crevices. 
Related SpeciesAlpheus "geminirostratus" Anker et al., in prep. [WA]; A. "pararostratus" Anker et al., in prep. [EA]; A. aff. rostratus (Anker, pers. obs.) [IWP]; A. paracrinitus Miers, 1881 [WA-CA-EA]; A. "subparacrinitus" (Anker et al., in prep.) [WA]; A. aff. paracrinitus (Anker, pers. obs.) [IWP]; A. "coeruleocinctus" Anker et al., in prep. [EA]; A. bengalensis Coutière, 1905 [IWP]; more distantly: A. alpheopsides Coutière, 1905 [IWP]; A. paralpheopsides Coutière, 1905 [IWP]; A. tenuipes De Man, 1910 [IWP]; A. mitis Dana, 1852 [IWP]. Alpheus rostratus belongs to the "spotted" clade (A. rostratus sub-complex) within the A. paracrinitus complex and differs from A. "geminirostratus", A. "pararostratus" and A. aff. rostratus by the distal half of the major chela palm being almost entirely brown (vs. bearing whitish or pale bands in the other three species) (see comparison photos). It differs from the sympatric A. fasciatus and all other species of the "spotless" clade (A. paracrinitus sub-complex) by the presence of dorsal spots on the third abdominal somite; from A. alpheopsides by the much longer rostrum and presence of small orbitorostral process (absent in A. alpheopsides); from A. paralpheopsides by the shape of the anterior margin of the orbital hoods and shorter major chela (see Coutière, 1905); from A. tenuipes by the presence of a subdistal tooth on the merus of the major cheliped, as well as color pattern (see comparison photos); and from the poorly known A. mitis by the relatively longer and more slender major chela. 
SizeBody length to about 18 mm. 
Color PatternSee photo
Molecular BarcodeGenBank number AF321360, AF321359, AF321358
Major ReferencesKim and Abele, 1988 [original description and illustrations]; Ríos, 1989 [records, figures]; Knowlton and Mills, 1992 [comparison of color patterns within A. paracrinitus complex]; Knowlton et al., 1993 [molecular phylogeny of American species of A. paracrinitus complex]; Ramos, 1995 [records, figures]; Williams et al., 2001 [molecular phylogeny of Atlantic/E Pacific members of A. paracrinitus complex]; Wicksten and Hendrickx, 2003 [distribution in E Pacific]; Anker et al., in prep. [taxonomic status, color photos, revision of A. paracrinitus complex]. 

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