Eohaustorius Estuarius Class: Multicrustacea, Malacostraca, Eumalacostraca

Phylum: Arthropoda, Crustacea

Eohaustorius estuarius Class: Multicrustacea, Malacostraca, Eumalacostraca

Order: Peracarida, Amphipoda, Amphilochidea, A sand-burrowing amphipod Lysianassida, Haustoriidira Family: Haustorioidea, Haustoriidae

Description Antenna 2: Peduncle articles large Size: Holotype is a female from Yaquina and flat, very setose and with multiarticuate Bay, Oregon that is 4 mm in length. Para- accessory flagellum (Fig. 3). types are 2.0–4.5 mm in length (measured Mouthparts: Mandible with palp and from the distal anterior end to the posterior always consisting of three articles telson) (Bosworth 1973). The illustrated spe- (Haustoriidae, Barnard 1969). Palp with cimens, collected from the lower Columbia smooth molar (Fig. 4). River, were up to 6 mm long (Fig. 1). Pereon: Color: White, in life and in preservation Coxae: Coxal plates one and two small (Bosworth 1973). and hidden beneath three and four (Fig. 1). General Morphology: The body of amphi- Coxal margins rounded and not pointed. pod crustaceans can be divided into three Gnathopod 1: Small, feeble and sim- major regions. The cephalon (head) or ple with article five longer than six (Kozloff cephalothorax includes antennules, anten- 1987) (Fig. 1). nae, mandibles, maxillae and maxillipeds Gnathopod 2: Feeble, small and mi- (collectively the mouthparts). Posterior to nutely chelate (Barnard 1969) (Fig. 5). the cephalon is the pereon (thorax) with Pereopods 3 through 7: Pereopods seven pairs of pereopods attached to pere- lack dactyls (i.e. have only six articles), are onites followed by the pleon (abdomen) with furry and fringed with long bristles six pairs of pleopods. The first three sets of (Eohaustorius, Kozloff 1987). Pereopod four pleopods are generally used for swimming, is smaller than pereopod three and is while the last three are simpler and surround reversed and positioned like pereopods 5–7, the telson at the animal posterior. The am- not like 1–3 (Barnard 1969; 1975) (Fig. 1). phipod family Haustoriidae are abundant in Pereopod five with only one fascicle (bundle) clean, fine sand in estuaries or marine habi- of spines on posterior edge of article six and tats were they swim and burrow upside- with articles five and six relatively equal in down (Chapman 2007). length (Bosworth 1973) (Fig. 1). Pereopod six Cephalon: like pereopod seven in length and general Rostrum: Short, visor-like and point- shape (i.e. not excessively long, Barnard ed (Fig. 2). 1975). Pereopod seven with posterior dorsal Eyes: Visible in live specimens (not corner of article two smoothly rounded, once preserved). Bright white in anterior without a cusp (arrow, Fig. 1) and with article distal corners of head (Bosworth 1973). five having two fascicles of spines on its Ovoid in shape, with irregular indentations, anterior edge (Fig. 1). not protruding above the surface. Eyes Pleon: probably not compound (Fig. 2). Pleonites: Third pleonites with a fine Antenna 1: Massive, setose and not posterior fringe (Fig. 1). geniculate (i.e. bent like a knee) (Fig. 2). Urosomites: Segments two and three

A publication of the University of Oregon Libraries and the Oregon Institute of Marine Biology Individual species: https://oimb.uoregon.edu/oregon-estuarine-invertebrates and full 3rd edition: http://hdl.handle.net/1794/18839 Email corrections to: [email protected]

Hiebert, T.C. 2015. Eohaustorius estuaris. 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.

not fused, but freely articulated (Kozloff was described from Lost Creek Beach, south 1987). Urosomites small and hidden be- of Newport, Oregon (Bosworth 1973). It has a neath pleonites (Figs. 1, 6). Third uropods small cusp on the dorsal posterior margin of each with two rami of equal length (Barnard article two of pereopod seven and it has only 1969) (Fig. 7). two fascicles of spines on the posterior edge Epimera: of article six or pereopod seven. This species Telson: Thin, flattened, setose lobes that is found high in the intertidal, from +0.6 to 3.6 are widely separated at bases by urosomites meters MLLW, and never in brackish water (Haustoriidae, Barnard 1975) (Fig. 6). (Bosworth 1973). Eohaustorius sawyeri, often Sexual Dimorphism: No obvious differ- found with E. brevicuspis, lacks the cusp on ences between males and females the seventh pereopod and has instead a (Bosworth 1973). bulge on the posterior edge of the second article (of the seventh pereopod). The Possible Misidentifications posterior edge of the sixth article of pereopod The Phoxocephalidae and Hausto- seven has four fascicles of spines. This riidae are morphologically similar gammarid species is subtidal, marine and found from amphipod families. Unlike the latter, Phoxo- MLLW down to -0.76 meters. It has not been cephalidae have very dissimilar pereopods found in estuarine conditions (Bosworth six and seven: six is long and seven has a 1973). The species most likely to be broad second article (see Eobrolgus spino- confused with E. estuarius, and which is also sus). In the phoxocephalids, the fourth pe- found occasionally in the more marine reopod is not reversed as in the Haustorii- portions of estuaries, is E. washingtonianus. dae, and although the rostrum is visor-like, it Described from Puget Sound, it has also been is much longer. found in Coos Bay, Yaquina Bay, and in the The Haustoriidae have feeble gnatho- lower Columbia River. This species can be pods, a mandible with a 3-articled palp, and larger than E. estuarius, to 8 mm long (Kozloff spinose and setose pereopods. There are 1993). It has a prominent crescent-shaped many genera in the family, but Eohaustorius cusp on the dorsal posterior edge of article is the only genus in which all the pereopods two of pereopod seven and there are three (3–7) lack dactyls (Barnard 1969). It is also fascicles of spines on the posterior edge of the only genus of the family found in (and article six, pereopod five. In the Newport area restricted to) the northern Pacific (Barnard (e.g. Yaquina Bay), it overlaps with E. 1969), where there are six species brevicuspis intertidally, and with E. sawyeri (Chapman 2007). subtidally, being found from -0.76 to +1.22 Eohaustorius is the only genus in the meters (Bosworth 1973). Eohaustorius senci- family Haustoriidae that occurs exclusively llus has a first gnathopod with a sixth article on Pacific coasts (from Russia to Mexico, that is swollen and has an apical spine. The Slattery 1985; Bousfield and Hoover 1995). seventh article on gnathopod one is quite Six species in the genus have been found in long. This species lacks the cusp on article Oregon and four were described by Bos- two of pereopod seven (as does E. estuarius). worth in 1973 (Eohaustorius brevicuspis, E. Eohaustorius sencillus is found commonly sawyeri, E. washingtonianus and E. estua- from Monterey Bay, California (Barnard 1962) rius). Eohaustorius brevicuspis and E. to southern California. Eohaustorius barnardi sawyeri inhabit only the open coast is a subtidal species that occurs in fine sand, (Bosworth 1973). Eohaustorius brevicuspis and is 5 mm in length (Chapman 2007).

Ecological Information and E. washingtonianus and E. sawyeri are Range: Type locality is Yaquina Bay, OR found in the lower intertidal (Bosworth 1973). (Bosworth 1973) and known range includes Abundance: Densest at intertidal heights the entire northeastern Pacific (Chapman (Bosworth 1973). 2007). Life-History Information Local Distribution: Local distribution at Reproduction: Most amphipods have sepa- several Coos Bay sites, including the North rate sexes with some sex determination corre- Bend Airport extension site. Additional sites lated with environmental conditions (Straude in Oregon include Yaquina Bay (near the 1987). Females brood embryos in an external Hatfield Marine Science Center) and lower thoracic chamber and create a water flow by Columbia River. moving their pleopods to irrigate embryos. Habitat: Burrows in relatively clean, medium Development within this brood chamber is di- sized sand with a fairly high proportion of rect and individuals hatch as juveniles that organic material. An estuarine species, it is resemble small adults, with no larval stage. found on open coast only where there is Little is known about the reproduction and de- freshwater runoff (Bosworth 1973). velopment in E. estuarius, however Slattery Eohaustorius estuarius is a common species (1985) followed the reproduction of the conge- used in toxicity testing (e.g. Kohn et al. ner E. sencillus from Monterey Bay, Califor- 1994; Kravitz et al. 1999; Hecht and Boese nia, where mating occurs in the fall and ovig- 2002; Kuo et al. 2010; Greenstein et al. erous females can be found year round, with 2013; Ernst et al. 2014). It is the primary peaks in winter months. Brood sizes range species used in the San Francisco Bay from 3–6 eggs and egg sizes within the brood Estuary Regional Monitoring Program where are 430 µm and, upon hatching, are 800–900 it has been tested for sensitivity to a wide µm (Slattery 1985). variety of toxins including copper, Larva: Since most amphipods are direct de- fluoranthene, chlorpyrifos, permethrin, veloping, they lack a definite larval stage. In- bifenthrin and cypermethrin, the latter four stead this young developmental stage resem- toxins eliciting the most sensitive response bles small adults (e.g. Fig. 39.1, Wolff 2014). (Anderson et al. 2008). Eohaustorius Juvenile: Sexual maturity is reached after 2– estuarius also exhibited a dramatic, short- 3 molts in local species of the families Haus- term population decline following exposure toriidae (e.g. E. sencillus) and Phoxocepha- to carbaryl, an oyster farming pesticide lidae (e.g. Rhepoxynius fatigans, R. abronius) (Dumbauld et al. 2001). (Slattery 1985). Salinity: Brackish water (e.g. salinity at type Longevity: The longevity of E. estuarius is locality ranges from 1–25). not directly known, but local species in the Temperature: families Haustoriidae (e.g. E. sencillus) and Tidal Level: Intertidal and subtidal (up to 7 Phoxocephalidae (e.g. Rhepoxynius fatigans, meters deep, Bosworth 1973; Chapman R. abronius) are on an annual cycle (Slattery 2007). Some small permanent populations 1985). occur in high intertidal if freshwater stream Growth Rate: Amphipod growth occurs in runoff occurs (Bosworth 1973). conjunction with molting where the exoskele- Associates: Does not overlap with habitats ton is shed and replaced. Post-molt individu- Eohaustorius of other Oregon species, als will have soft shells as the cuticle gradual- E. estuarius where is found in brackish ly hardens (Ruppert et al. 2004). water, E. brevicuspis occurs mid-intertidally Hiebert, T.C. 2015. Eohaustorius estuaris. 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.

Food: Gammaridea, p. 545-611. In: The Light Predators: Fish, shorebirds. and Smith manual: intertidal invertebrates Behavior: Phoxocephalid and haustoriid from central California to Oregon. J. T. species tend to be very mobile and efficient Carlton (ed.). University of California burrowers (Slattery 1985) and E. estuarius is Press, Berkeley, CA. a strong digger, with an impressive 8. DUMBAULD, B. R., K. M. BROOKS, and armament of spines and setae used for M. H. POSEY. 2001. Response of an estu- digging. arine benthic community to application of the pesticide carbaryl and cultivation of Bibliography pacific oysters (Crassostrea gigas) in 1. ANDERSON, B. S., S. LOWE, B. M. Willapa Bay, Washington. Marine Pollution PHILLIPS, J. W. HUNT, J. VORHEES, S. Bulletin. 42:826-844. CLARK, and R. S. TJEERDEMA. 2008. 9. ERNST, W., K. DOE, A. COOK, L. BUR- Relative sensitivities of toxicity test proto- RIDGE, B. LALONDE, P. JACKMAN, J. G. cols with the amphipods Eohaustorius AUBE, and F. PAGE. 2014. Dispersion estuarius and Ampelisca abdita. Ecotoxi- and toxicity to non-target crustaceans of cology and Environmental Safety. 69:24- azamethiphos and deltamethrin after sea 31. lice treatments on farmed salmon, Salmo 2. BARNARD, J. L. 1962. A new species of solar. Aquaculture. 424:104-112. sand-burrowing Amphipoda from Califor- 10. GREENSTEIN, D., S. BAY, M. JACOBE, nia. Bulletin of the Southern California C. BARTON, K. SAKAMOTO, D. YOUNG, Academy of Sciences. 61:249-252. K. RITTER, and K. SCHIFF. 2013. Re- 3. —. 1969. The Families and genera of gional assessment of marine and estua- marine Gammaridean Amphipoda, p. rine sediment toxicity in Southern Califor- 535. In: United States National Museum nia, USA. Environmental Monitoring and Bulletin, Washington, DC. Assessment. 185:2055-2065. 4. —. 1975. Phylum Anthropoda: Crusta- 11. HECHT, S., and B. L. BOESE. 2002. Sen- cea, Amphipoda: Gammaridea, p. 313- sitivity of an infaunal amphipod, Eohausto- 366. In: Light's manual: intertidal inverte- rius estuarius, to acute waterborne expo- brates of the central California coast. S. sures of 4-nonylphenol: evidence of a toxic F. Light, R. I. Smith, and J. T. Carlton hangover. Environmental Toxicology and (eds.). University of California Press, Chemistry. 21:816-819. Berkeley. 12. KOHN, N. P., J. Q. WORD, D. K. NIYOGI, 5. BOSWORTH, W. S. J. 1973. Three new L. T. ROSS, T. DILLON, and D. W. species of Eohaustorius (Amphipoda: MOORE. 1994. Acute toxicity of ammonia Haustoriidae) from the Oregon coast. to four species of marine amphipod. Ma- Crustaceana. 25:253-260. rine Environmental Research. 38:1-15. 6. BOUSFIELD, E. L., and P. HOOVER. 13. KOZLOFF, E. N. 1987. Marine inverte- 1995. The amphipod superfamily Ponto- brates of the Pacific Northwest. University poreioidea on the Pacific coast of North of Washington Press, Seattle. America. 1. Family Haustoriidae. Genus 14. —. 1993. Seashore life of the northern Pa- Eohaustorius (J.L. Barnard): systematics cific coast: an illustrated guide to northern and distributional ecology. Amphipacifi- California, Oregon, Washington, and Brit- ca. 2:35-63. ish Columbia. University of Washington 7. CHAPMAN, J. W. 2007. Amphipoda: Press, Seattle, WA.

15. KRAVITZ, M. J., J. O. LAMBERSON, S. P. FERRARO, R. C. SWARTZ, B. L. BO- ESE, and D. T. SPECHT. 1999. Avoid- ance response of the estuarine amphipod Eohaustorius estuarius to polycyclic aromatic hydrocarbon-contaminated, field-collected sediments. Environmental Toxicology and Chemistry. 18:1232- 1235. 16. KUO, J., C. BUDAY, G. VAN AGGELEN, M. G. IKONOMOU, and J. PASTERNAK. 2010. Acute toxicity of emamectin benzo- ate and its desmethyl metabolite to Eo- haustorius estuarius. Environmental Tox- icology and Chemistry. 29:1816-1820. 17. RUPPERT, E.E., R.S. FOX, and R.D BARNES. 2004. Invertebrate zoology: a functional evolutionary approach, 7th Edi- tion. Thomson Brooks/Cole, Belmont, CA. 18. SLATTERY, P. N. 1985. Life histories of infaunal amphipods from subtidal sands of Monterey Bay, California. Journal of Crustacean Biology. 5:635-649. 19. STRAUD, C. P. 1987. Phylum or Sub- phylum Crustacea, Class Malacostraca, Order Amphipoda, p. 424-431. In: Repro- duction and development of marine invertebrates of the northern Pacific coast. M. F. Strathman (ed.). University of Washington Press, Seattle, WA. 20. WOLFF, C. 2014. Amphipoda, p. 206- 209. In: Atlas of crustacean larvae. J.W. Martin, J. Olesen, and J. T. Høeg (eds.). Johns Hopkins University Press, Balti- more. Updated 2015 T.C. Hiebert