Alpheus heterochaelis

Alpheus heterochaelis Say, 1818

Original Description	Alpheus heterochaelis Say, 1818: 243.
Classification	Arthropoda: Crustacea: Malacostraca: Decapoda: Alpheidae.
Synonymy	Crangon heterochaelis (Say, 1818), Alpheus lutarius (de Saussure, 1857).
Type Locality	Amelia Island, Florida (symbol on the map).
Type Material	Neotype: USNM 0000000, in ethanol and excellent condition.
Common Name	Big-claw snapping shrimp.
Taxonomic Status	Valid.
Geographic Distribution	Western Atlantic: North Carolina and Gulf of Mexico to NE Brazil (see map).
Frequency	Locally common, for example abundant in channels of the Everglades National Park (Hendrix, 1971) and in Florida mangrove-Juncus systems (Williams, 1984).
Habitat	Estuaries, mudflats close to mangroves, salt marshes, brackish to almost freshwater lakes; on mud bottoms with rocks and oyster clumps; tolerates very low salinities (down to 2 ‰, Williams, 1984).
Depth Range	Intertidal to about 9 m.
Life History and Behavior	Lives in male-female pairs in burrows made in mud or firm sand mixed with mud, sometimes under rocks and mangrove debris. Males tend to seek females by chemical cues, although snapping is also used in intra- and interspecific communication, indicating size, sex, species and location of the emitter (Schein, 1977). Agonistic encounters are usually highly ritualized; the brightly colored plunger visible when the claw is opened may be used as visual signal (Hughes, 1996). Shrimps also communicate via water currents (Herberholtz and Schmitz, 2001). Recent studies on snapping in A. heterochaelis demonstrated that the sound is actually produced by implosion of a cavitation bubble, by-producing a very short and weak flash, a phenomenon termed "shrimpoluminescence" (for details see Versluis et al., 2000 and Lohse et al., 2001). This snapping shrimp actively uses its snapping claw to crash hard clams, Mercenaria mercenaria (Beal, 1983), and may inflict serious injuries to mud crabs, Eurypanopeus depressus (Schultz et al., 1998). On the other hand, A. heterochaelis locally associates with the xanthid mud crab Panopeus herbstii (Silliman et al., 2003). The larval development appears to be abbreviated compared to that of the other Alpheus species (Knowlton, 1973).
Related Species	Alpheus firmus Kim and Abele, 1988 [EP]; A. pontederiae Rochebrune, 1883 [EA-WA]; A. "virginiae" Anker et al., in prep. [EA]. Alpheus heterochaelis can be separated from A. firmus by the much shorter penultimate segment of the third maxilliped; from A. pontederiae by the absence of a distinct oblique ridge on the pollex of the major chela; and from all three species by the color pattern, especially the conspicuously marbled major claw (see comparison photos).
Size	Body length to at least 45 mm.
Color Pattern	See photo.
Molecular Barcode	GenBank number 00000000.
Remarks	Alpheus heterochaelis is by far the most studied alpheid shrimp and also one of the best studied decapods in general (see references below). This species has also been used in studies on neurophysiology of claw regeneration (numerous studies by M.M. Quigley, D. Mellon, C.K. Govind, J.A. Wilson and others) and larval development (studies by P.S. Gross, R.E. Knowlton).
Major References	Say, 1818 [original description]; Hay and Shore, 1918 [figures, notes on ecology, as Crangon heterochaelis]; Hendrix, 1971 [Florida records, notes on biology]; Knowlton, 1973 [larval development]; Ritzmann, 1974 [snapping behavior]; Schein, 1975; Schein, 1977 [aggressive and social behavior, communication]; Conover and Miller, 1978 [importance of snapping claw in territorial and pairing behavior]; Beal, 1983 [predation on clams]; Christoffersen, 1984 [taxonomic revision, records from Brazil, comparison with related species]; Williams, 1984 [synthesis of general biology]; McClure and Greenbaum, 1994 [biochemical variation]; McClure, 1995 [redescription, neotype designation]; Hughes, 1996 [role of major claw in intraspecific agonistic behavior]; McClure and Wicksten, 1997 [records, taxonomic notes, figures]; Herberholtz and Schmitz, 1999 [snapping mechanism: visualization of water jet]; Versluis et al., 2000 [snapping through cavitation bubbles]; Herberholtz and Schmitz, 2001 [signaling via water currents]; Lohse et al., 2001 [schrimpoluminescence]; Silliman et al., 2003 [associations with xanthid crabs].

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