Rhithropanopeus Harrisii Class: Multicrustacea, Malacostraca, Eumalacostraca

Home , Panopeidae, Panopeus (genus), Rhithropanopeus harrisii

Phylum: Arthropoda, Crustacea

Rhithropanopeus harrisii Class: Multicrustacea, Malacostraca, Eumalacostraca

Order: Eucarida, Decapoda, Pleocyemata, Brachyura, The ghost shrimp Eubrachyura, Heterotremata Family: Xanthoidea, Panopeidae

Taxonomy: The large and taxonomically trally (Decapoda, Kuris et al. 2007). problematic family, Xanthidae was divided Cephalothorax: into eight smaller families by Guinot (1978). Eyes: Frontal and fill orbits. This included Panopeidae, to which R. har- Antenna: risii belongs, and Pilumnidae (Pilumnus) Mouthparts: The mouth of decapod placing emphasis on more discrete charac- crustaceans comprises six pairs of appendag- ters (e.g. pleopod morphology) than previ- es including one pair of mandibles (on either ously used (e.g. carapace and chelae mor- side of the mouth), two pairs of maxillae and phology) (Martin and Abele 1986; Schubart three pairs of maxillipeds. The maxillae and et al. 2000). Rhithropanopeus was separat- maxillipeds attach posterior to the mouth and ed from Panopeus based on unique pleopod extend to cover the mandibles (Ruppert et al. morphology (Martin and Abele 1986). Thus, 2004). known synonyms previously used for R. har- Carapace: Sub-quadrate, almost trap- risii include Panopeus wurdemannii and ezoidal and wider than long. Carapace sides Pilumnus harrisii (Wicksten 2012). converge slightly. Front truncate and posterior broad with greatest width at fourth lateral Description tooth (Ryan 1956). Prominent horizontal dor- Size: Male carapace generally 16 mm in sal ridges (Rathbun 1930) (Fig. 1) (Ryan length and female carapaces are usually 12 1956). mm in length (Wicksten 2012). Type speci- Frontal Area: Front truncate and less men was 19 mm (Rathbun 1930), and than a third as wide as carapace. Frontal among Coos Bay specimens 36% (both margin straight, double-edged, channeled and sexes) measured at least 6 mm in width thick with a triangular median notch (Figs. 1, (Pisciotto 1977) and males were larger than 2). females (Ryan 1956). Weight rarely over Teeth: Five carapace teeth. The first, four grams (San Francisco Bay, Smith antero-lateral tooth fused with the postorbital 1967). angle and followed by 2–3 anterolateral teeth. Color: Dull green to brown dorsally, pale Last three teeth are dentate, pointing forward white ventrally. Dactyls whitish (Rathbun with the last tooth smallest (Fig. 2) (Wicksten 1930; see Fig. in Wicksten 2012). 2012). General Morphology: The body of decapod Pereopods: Long, slender com- crustaceans can be divided into the cepha- pressed and covered with fine hairs (Fig. 1). lothorax (fused head and thorax) and abdo- Chelipeds: Unequal, heavy, with short men. They have a large plate-like carapace fixed finger and curved dactyl. Minor chelae dorsally, beneath which are five pairs of tho- with longer fixed finger and dactyl. Carpus racic appendages (see chelipeds and pere- with internal tooth (Wicksten 2012). Chelae opods) and three pairs of maxillipeds (see smooth (older individuals), or with lines and mouthparts). The abdomen and associat- granules (young individuals) (Fig. 4). ed appendages are reduced and folded ven-

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. Rhithropanopeus harrisii. 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, Charles- ton, OR.

Abdomen (Pleon): Male abdomen narrow oregonensis in the lower parts of bays where (see Sexual Dimorphism) with five seg- they can co-occur. ments with third segment not contiguous Ecological Information with coxa of the last pair of legs (Fig. 3). Range: Type locality is the Cambridge Marsh- Terminal segment rounded (Fig. 3) (Rathbun es and the Charles River, Massachusetts 1930). (Wicksten 2012). Native to the Gulf of St. Telson & Uropods: Lawrence, Canada to Veracruz, Mexico and Sexual Dimorphism: Male and female introduced to northern Europe (e.g. Holland) brachyuran crabs are generally easy to dif- and the west coast of North America (San ferentiate. The most conspicuous feature, Francisco and Coos Bay) in 1940 (Garth and the abdomen, is narrow and triangular in Abbott 1980; Puls 2001; Wicksten 2012). males while it is wide and flap-like in fe- Local Distribution: Probably introduced to males (Brachyura, Kuris et al. 2007). San Francisco, California with eastern oyster Possible Misidentifications spat (Crassostrea virginica) in 1940 and Two panopeid genera occur locally; expanded northward to Coos Bay, Oregon Rhithropanopeus and Lophopanopeus (Ricketts and Calvin 1971). Oregon distribu- (Kuris et al. 2007). Rhithropanopeus, cur- tion includes Haynes Inlet, Coos River rently monotypic, is characterized by unique (Pisciotto 1977), Netarts Bay (Stout 1976) and pleopod morphology, particularly the lack of Yaquina Bay (Pisciotto 1977). a lateral tooth. Additional characters include Habitat: Sloughs, under rocks and in mud a median process that is rounded and with banks of estuaries, where it burrows (Puls one long central spine and 3–4 long spines 2001; Kuris et al. 2007). Tolerates a diversity laterally (Martin and Abele 1986). Further- of conditions (see Salinity and Tempera- more, R. harrisii has white dactyls (or fin- ture), but prefers some kind of shelter (e.g. gers) while local members of Lophopanope- oyster beds, Chesapeake Bay, Ryan 1956). us have black dactyls and are not found in Salinity: Euryhaline and tolerant of a wide brackish water (Kuris et al. 2007). Addition- range in salinity, usually brackish to freshwa- al characters of the genus Lophopanopeus ter (Rathbun 1930; Garth and Abbott 1980; include tri-lobed pleopods with accessory Pisciotto 1977; Forward 2009). This species processes extending acutely from the main osmoregulates very effectively, increasing ex- shaft, a medial lobe that is deeply furrowed cretion of urine in dilute waters and adjusting and a simple lateral tooth (Martin and Abele the permeability of the body wall (Garth and 1986). The two local species can be differ- Abbott 1980). Adult salinity tolerance is gen- entiated by the distal segments of ambulato- erally between 0–18, but can range to salini- ry legs that are hairy in L. bellus and smooth ties of up to 40 (Forward 2009). Larvae de- in L. leucomanus (Kuris et al. 2007). velop normally (in lab) at salinities of 5–35, Rhithropanopeus can also be mistak- while no larvae survive at salinities less than 1 en for the shore crab, Hemigrapsus ore- (Costlow et al. 1966). Additionally, zoeae gonensis, but Rhithropanopeus has strong were found in salinities of 4–23.5 (greatest dorsal ridges, three side spurs (Ricketts and number at 15, Bousfield 1955). It is thought Calvin 1971) (last three pointed antero- that tolerance of lower salinities is the result of lateral teeth), slightly convergent sides and reproductive refuge from the rhizocephalan long, slender legs. Rhithropanopeus harrisii parasite, Loxothylaxus panopaei, that settles sometimes competes for food with H. onto R. harrisii larvae at salinities above 10

(Forward 2009). This parasite is currently ment of adults, as the tide is not to enable lar- only present in Chesapeake Bay on the east vae to move offshore as is seen in other coast, and the Gulf of Mexico, where brachyurans (Forward 2009). infection rates are affected by salinity and Larva: The larvae and larval biology of R. spatial separation between host populations harrisii are well described (Connolly 1925; (Grosholz and Ruiz 1995). Costlow and Bookhout 1971; Forward 2009; Temperature: Adults and larvae tolerant of Marco-Herrero et al. 2014). Larval develop- a wide temperature range, from 7°to 35° C ment in R. harrisii proceeds via a prezoea, (Costlow et al. 1966; Vernberg and several zoea (four total) and a final megalo- Vernberg 1972; Forward 2009). pae stage, each marked by a molt (Jaffe et al. Temperature range unknown for planktonic 1987; Puls 2001; Forward 2009). The zoea larvae (Costlow et al. 1966), but their are planktotrophic and have large compound retention in the estuary (rather than moving eyes and four spines: one each dorsal and offshore) suggests a wide tolerance rostral and two lateral (see Fig. 54.5, Martin (Forward 2009). Found in Coos Bay at 2014). The rostrum is longer than the dorsal temperatures ranging from 9–16° (October spine (Connolly 1925; Puls 2001) and lateral to December, Pisciotto 1977). spines on the distal ends of the fifth ab- Tidal Level: High intertidal to depths of ap- dominal segments are very long (Connolly proximately 37 m (Wicksten 2012). 1925). Larval size at each of four stages is Associates: Parasitic rhizocephalan, Lox- outlined in Connolly (1925). Megalopae are othylaxus panopaei, infests R. harrisii in re- 1.1 x 1.0 mm (Connolly 1925; Puls 2001; see gions where salinity is higher than 10. The Fig. 54.9, Martin 2014), have a carapace with L. panopaei cyprids settle on R. harrisii meg- uneven surface and rostrum with median tri- alopae (Forward 2009). angular tooth, as seen in adults (see Frontal Abundance: Can be the dominant species Area) (Connolly 1925). Wild-caught megalo- and is found in nearly every arm of Chesa- pae identified using DNA sequence data were peake Bay, but only occurs in widely scat- described by Marco-Herrero et al. in 2014. tered patches (where it is abundant) in Ore- The megalopae of R. harrisii are unique gon estuaries (Ryan 1956; Kuris et al. among panopeids in lacking horns at the ros- 2007). trum base. Other differentiating characters include the number of segments of the anten- Life-History Information nular flagellum (six in R. harrisii) and the ab- Reproduction: Reproductive timing varies sence of a recurved spine on the cheliped is- with latitude. Individuals in northern lati- chium (for typical panopeid spine see Fig. tudes are reproductive from July–August, 54.7, Martin 2014). those in mid-latitude from April–September Juvenile: Can be recognized by their granu- and southern individuals from April– lated chelae. November (Forward 2009). In Chesapeake Longevity: Less than two years (Grosholz Bay, females are ovigerous in summer and and Ruiz 1995). early fall (Ryan 1956). Females do not mi- Growth Rate: Growth occurs in conjunction grate to more saline waters to release larvae with molting. In pre-molting periods the epi- (Costlow et al. 1966). In regions with a diur- dermis separates from the old cuticle and a nal tidal cycle, larvae are released two hours dramatic increase in epidermal cell growth oc- following high tide, presumably to reduce curs. Post-molt individuals will have soft larval exposure to the low salinity environ- shells until a thin membranous layer is depos-

ited and the cuticle gradually hardens. Dur- University Press, New York. ing a molt decapods have the ability to re- 5. FITZGERALD, T. P., R. B. FORWARD, generate limbs that were previously autoto- and R. A. TANKERSLEY. 1998. Metamor- mized (Kuris et al. 2007). Experiments in R. phosis of the estuarine crab Rhithropanop- harrisii showed that eyestalk removal in- eus harrisii: effect of water type and adult creased growth rate up to two times and that odor. Marine Ecology Progress Series. growth resulted from cell proliferation, not 165:217-223. enlargement (Freeman et al. 1983). Sexual 6. FORWARD, R. B. J. 2009. Larval biology maturity in R. harrisii is probably reached of the crab Rhithropanopeus harrisii during the second summer and the total (Gould): a synthesis. Biological Bulletin. number of juvenile in-stars (molts) is not 216:243-256. known (Ryan 1956). 7. FREEMAN, J. A., T. L. WEST, and J. D. Food: Algae and small crabs (sometimes COSTLOW. 1983. Post larval growth in including juvenile conspecifics). Rhithro- juvenile Rhithropanopeus harrissii. Biologi- panopeus harrisii is a nocturnal feeder. cal Bulletin. 165:409-415. Predators: 8. GARTH, J. S., and D. P. ABBOTT. 1980. Behavior: Xanthid and panopeid crabs are Brachyura: the true crabs, p. 594-630. In: generally slow-moving, inactive crabs, Intertidal invertebrates of California. R. H. sometimes playing dead when disturbed Morris, D. P. Abbott, and E. C. Haderlie (Kuris et al. 2007). Rhithropanopeus harrisii (eds.). Stanford University Press, Stan- hides under rocks and is less active than ford, CA. Hemigrapsus oregonensis, with which it co- 9. GROSHOLZ, E. D., and G. M. RUIZ. occurs. 1995. Does spatial heterogeneity and ge- netic variation in populations of the Bibliography Xanthid crab Rhithropanopeus harrissii 1. BOUSFIELD, E. L. 1955. Ecological con- (Gould) influence the prevalence of an in- trol of the occurrence of barnacles in the troduced parasitic castrator? Journal of Miramichi Estuary. Bulletin of the Nation- Experimental Marine Biology and Ecology. al Museum of Canada. 137:1-69. 187:129-145. 2. CONNOLLY, C. J. 1925. The larval stag- 10. GUINOT, D. 1978. Principles of an evolu- es and megalops of Rhithropanopeus tive classificaton of Brachyura-Decapoda- harrisii (Gould). Contributions to Canadi- Crustacea. Bulletin Biologique de la an Biology (NS). 2:327-33. France et de la Belgique. 112:211-292. 3. COSTLOW, J. D., C. G. BOOKHOUT, 11. JAFFE, L. A., C. F. NYBLADE, R. B. FOR- and R. J. MONROE. 1966. Studies of the WARD, and S. SULKIN. 1987. Phylum or larval development of the crab, Rhithro- subphylum Crustacea, class Malacostra- panopeus harrisii: I. The effect of salinity ca, order Decapoda, Brachyura, p. 451- and temperature on larval development. 475. In: Reproduction and development of Physiological Zoology. 39:81-100. marine invertebrates of the northern Pacif- 4. COSTLOW, J. D. J., and C. G. BOOK- ic coast. M. F. Strathmann (ed.). University HOUT. 1971. The Effect of cyclic temper- of Washington Press, Seattle, WA. atures on larval development in the mud 12. KURIS, A. M., P. S. SADEGHIAN, J. T. crab Rhithropanopeus harrisii, p. 211- CARLTON, and E. CAMPOS. 2007. De- 220. In: Fourth European marine biology capoda, p. 632-656. In: The Light and symposium. D. J. Crisp (ed.). Cambridge Smith manual: intertidal invertebrates from

central California to Oregon. J. T. Carlton American Midland Naturalist. 56:138-162. (ed.). University of California Press, 22. SCHUBART, C. D., J. E. NEIGEL, and D. Berkeley, CA. L. FELDER. 2000. Molecular phylogeny of 13. MARCO-HERRERO, E., J. IGNACIO mud crabs (Brachyura: Panopeidae) from GONZALEZ-GORDILLO, and J. A. the northwestern Atlantic and the role of CUESTA. 2014. Morphology of the meg- morphological stasis and convergence. alopa of the mud crab, Rhithropanopeus Marine Biology. 137:11-18. harrisii (Gould, 1841) (Decapoda: Brach- 23. SMITH, R. I. 1967. Osmotic regulation and yura: Panopeidae), identified by DNA adaptive reduction of water permeability in barcode. Helgoland Marine Research. a brackish-water crab, Rhithropaneus har- 68:201-208. risii. Biological Bulletin. 133:643-658. 14. MARTIN, J. W. 2014. Brachyura, p. 295- 24. STOUT, H., and S. V. SHABICA. 1976. 310. In: Atlas of crustacean larvae. J. W. The natural resources and human utiliza- Martin, J. Olesen, and J. T. Høeg (eds.). tion of Netarts Bay, Oregon. Oregon State Johns Hopkins University Press, Balti- Universtiy, Corvallis, Oregon. more, MD. 25. VERNBERG, W. B., and V. F.J. 1972. En- 15. MARTIN, J. W., and L. G. ABELE. 1986. vironmental physiology of marine animals. Notes on male pleopod morphology in Springer-Verlag, New York. the Brachyuran crab family Panopeidae 26. WICKSTEN, M. K. 2011. Decapod crusta- Ortmann, 1893, Sensu Guinot (1978) cea of the Californian and Oregonian Zoo- (Decapoda). Crustaceana. 50:182-198. geographic Provinces. http:// 16. PISCIOTTO, R. J. 1977. The distribution escholarship.org/uc/item/7sk9t2dz. of Rhithropanopeus harrisii in Coos Bay. Scripps Institution of Oceanography, UC Oregon Institute of Marine Biology San Diego, San Diego, CA. (University of Oregon). Updated 2015 17. PULS, A. L. 2001. Arthropoda: Decapo- T.C. Hiebert da, p. 179-250. In: Identification guide to larval marine invertebrates of the Pacific Northwest. A. Shanks (ed.). Oregon State University Press, Corvallis, OR. 18. RATHBUN, M. J. 1930. The Cancroid crabs of America of the families Euryali- dae, Portunidae, Atelecyclidae, Cancri- dae and Xanthidae. U.S. Government Printing Office, Washington, D.C. 19. RICKETTS, E. F., and J. CALVIN. 1971. Between Pacific tides. Stanford Universi- ty Press, Stanford, California. 20. RUPPERT, E. E., R. S. FOX, and R. D. BARNES. 2004. Invertebrate zoology: a functional evolutionary approach. Thom- son Brooks/Cole, Belmont, CA. 21. RYAN, E. P. 1956. Observations on the life histories and distribution of the Xanthid crabs of Chesapeake Bay.