Traskorchestia Traskiana Class: Malacostraca Order: Amphipoda, Gammaridea a Beach Hopper Family: Talitridae

Phylum: Arthropoda, Crustacea Traskorchestia traskiana Class: Malacostraca Order: Amphipoda, Gammaridea A beach hopper Family: Talitridae Taxonomy: The genus Traskorchestia was Eyes: Eyes large and oval in shape designated in 1982 by Bousfield based on (Fig. 1). taxonomic characters and individuals Antenna 1: Very short, consisting of collected from field expeditions in 1955 from five articles (Fig. 1) (Stebbing 1906). Alaska to Baja, California (for characters see Antenna 2: Short, peduncle not Figs. 1–3, 5, Bousfield 1982). Many thickened, flagellum with 16 articles (16 in Traskorchestia species, including T. traskiana males, 12 in females) (Stebbing 1906). Both (e.g. O. traskiana) were previously members first and second antennae are less massive of Orchestia (Bousfield 1982; Bousfield 2007). than the beach hoppers found on the more open coast (e.g. M. pugettensis Ricketts and Description Calvin 1971). Size: The illustrated individual (from South Mouthparts: Mandible without palp Slough of Coos Bay) is 20 mm in length. (Fig. 2) (Talitridae) and maxilliped with four Individuals can be 13 mm or a little more articles, although the fourth is not well (Barnard 1975). developed (Fig. 4) (Barnard 1954). Color: Pale brown, orange antennae. Pereon: Overall body color dull green or gray-brown Coxae: The plate of coxa one is with slightly blue legs (see Plate 19, Kozloff about half as long as coxa two (Fig. 1). 1993) (Ricketts and Calvin 1971). Gnathopod 1: Dactyl of gnathopod General Morphology: The body of one is slender and subchelate, especially in amphipod crustaceans can be divided into mature males, although not as simple as in three major regions. The cephalon (head) or Megalorchestia (see M. pugettensis). cephalothorax includes antennules, antennae, Translucent process on article four (Fig. 5). mandibles, maxillae and maxillipeds Gnathopod 2: Smooth convex palm (collectively the mouthparts). Posterior to with no spine at hinge of articles six and the cephalon is the pereon (thorax) with seven (Fig. 6). seven pairs of pereopods attached to Pereopods 3 through 7: Pereopod pereonites followed by the pleon (abdomen) seven longer than six (Barnard 1975). with six pairs of pleopods. The first three sets Pleon: Pleopods strong, biramous with the of pleopods are generally used for swimming, first three about equal in size and branches while the last three are simpler and surround with 7–10 segments (not figured) (Barnard the telson at the animal posterior. Talitrid 1975). amphipods are in the suborder Gammaridea, Pleonites: Pleonites five and six not one of the largest groups of amphipods in fused (Fig. 1) (Barnard 1975). marine and estuarine habitats. They have Urosomites: The third uropod is smooth bodies that are only slightly uniramous (Talitridae, Barnard 1954) with compressed, are commonly called beach ramus shorter than peduncle and narrowing hoppers and can be highly abundant on distally (Barnard 1975) (Fig. 3). coastal beaches, particularly at night Epimera: (Bousfield 2007). Traskorchestia species are Telson: Telson puffy, split (not visible in characterized by smooth unmodified bodies, lateral view) and with several spines (Fig. 3) lateral eyes and their small to medium size (Barnard 1975). (for key see Bousfield 1982). Sexual Dimorphism: Males generally larger Cephalon: than females and with larger gnathopods. Rostrum: Rostrum simple (Fig. 1). Populations in Washington state were Hiebert, T.C. 2015. Traskorchestia traskiana. In: Oregon Estuarine Invertebrates: Rudys' Illustrated Guide to Common Species, 3rd ed. T.C. Hiebert, B.A. Butler and A.L. Shanks (eds.). University of Oregon Libraries and Oregon Institute of Marine Biology, Charleston, OR. A publication of the University of Oregon Libraries and the Oregon Institute of Marine Biology Individual species: http://hdl.handle.net/1794/12734 and full 3rd edition: http://hdl.handle.net/1794/18839 Email corrections to: [email protected] dominated by females (63% compared to second gnathopod has a sinuous dactyl and 37% male, Koch 1990). a triangular tooth near the hinge. Possible Misidentifications Ecological Information The Talitridae are a family of gammarid Range: Type locality is in California amphipods called beach hoppers and are (Bousfield 1982). Known range includes ubiquitous in damp sands, where they live Aleutian Islands in Alaska to Washington within clumps of seaweed. They survive well state and south to Magdalena Bay, Baja in air. Talitridae are characterized by a single California (Barnard 1954; Koch 1989b). branched third uropod (Figs. 1, 4 Local Distribution: Locally present at Megalorchestia pugettensis) and a mandible several locations in Coos Bay, at North Bay without a palp (Fig. 2). Nine local talitrid and Cape Arago (Barnard 1954). species are currently reported (Bousfield Habitat: Rocky and/or sandy beaches with 2007) including six Megalorchestia, two algae, salt marshes (under debris and Traskorchestia and one Transorchestia boards) (Barnard 1975). Also occurs under species. Some authors differentiate driftwood on high protected beaches and Megalorchestia species as sand hoppers inner Salicornia marshes (e.g. Metcalf (intertidal on sandy beaches), while Preserve) (Kozloff 1993). Beach fleas Traskorchestia species as beach fleas (Traskorchestia species) are differentiated (intertidal in coastal leaf-litter) (Bousfield from sand hoppers (Megalorchestia species) 1982; Pelletier et al. 2011). in that the former group tend not to modify The genus Megalorchestia are found their habitat substrate (Bousfield 1982). on exposed beaches and are usually larger Salinity: Euryhaline. Salinity tolerance than Traskorchestia. Species in the latter ranges from brackish slough (Ricketts and genus have subchelate first gnathopods, not Calvin 1971) to high beaches of salty bays simple ones, and slender first gnathopod (Kozloff 1993) and the outer coast (Barnard dactyls, not heavy ones. The seventh 1954). The majority of individuals tested pereopods are also longer than the sixth, (95%) survived for 24 hours in salinities while the reverse is true in Megalorchestia. ranging from 2.5 to 50 (Koch 1991). The third uropods narrows and branches in Temperature: Up to 30–38˚C (Morritt and Traskorchestia, but is not broad. Spicer 1998). Traskorchestia species are larger Tidal Level: Usually along the wrack line, but than Megalorchestia and found on exposed also found more than 20 meters above beaches. Traskorchestia georgiana is up to tidewater (Ricketts and Calvin 1971). A 13.5 mm in length and is found with T. supralittoral species that can withstand traskiana in the drift line on rocky beaches desiccation of up to 25% of body water loss and amongst seagrass and algal debris. (Morritt and Spicer 1998), although Traskorchestia georgiana has weak desiccation resistance decreases in smaller pleopods with 4–6 segments on the rami and individuals (Koch 1989b). Individuals prefer its first gnathopod lacks the process on the not to be inundated with water and will fourth article (male) that is found on T. migrate upshore with an incoming tide (Koch traskiana (Bousfield 1982). 1989a). Transorchestia enigmatica is another Associates: In Metcalf Preserve, associates local talitrid amphipod species that is up to include other amphipods, sphaeromid isopods 15 mm in length. It was introduced in solid and the gastropod, Ovatella. Talitrid ballast from the southern hemisphere and is amphipods are known to host rhabditid now found in Lake Merritt near San nematodes under their dorsal pereonites (e.g. Francisco Bay, California (Bousfield and Megalorchestia californiana and M. Carlton 1967). It is a member of the T. corniculata, Rigby 1996) as well as within the chiliensis species group, an introduced intersegmental spaces in T. traskiana species found under debris on sandy (Adamson and Rigby 1996). Talitrid beaches. Transorchestia chiliensis has a amphipods also host and transport mites of long, inflated second antenna and the Uropodina, Dermanyssina and Acaridida Hiebert, T.C. 2015. Traskorchestia traskiana. In: Oregon Estuarine Invertebrates: Rudys' Illustrated Guide to Common Species, 3rd ed. T.C. Hiebert, B.A. Butler and A.L. Shanks (eds.). University of Oregon Libraries and Oregon Institute of Marine Biology, Charleston, OR. (Pugh et al. 1997) and an additional 12 mite Growth Rate: Amphipod growth occurs in species in the genus Traskorchestianoetus conjunction with molting where the were reported from Traskorchestia traskiana exoskeleton is shed and replaced. Post-molt in Vancouver Island, Canada (Fain and individuals will have soft shells as the cuticle Colloff 1990). Black gill syndrome (BGS) is gradually hardens. During a molt, arthrorpods found in many decapod crustaceans and has have the ability to regenerate limbs that were been reported for Traskorchestia traskiana. It previously autotomized (Kuris et al. 2007). can be caused by a variety of things including Growth in T. traskiana proceeds as one bacterial, fungal or protozoan infections. BGS podomere (leg bearing segment) per molt for causes darkening and, ultimately, loss of gills up to 13 and 16 podomeres in females and which results in a reduction of oxygen uptake males, respectively. Growth of antennal (Spicer 2013). Spicer (2013) found that the segments is positively correlated with overall osmoregulatory ability of high-shore body size (Page 1979). individuals was most negatively affected by Food: Scavenges in debris for detritus and BGS, suggesting this syndrome could reduce tends to prefer aged and decomposing

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