Phylum: Arthropoda, Crustacea

Hemigrapsus oregonensis Class: Multicrustacea, , Eumalacostraca

A hairy shore Order: Eucarida, , , Brachyura, Eubrachyura, Family: , , Varuninae

Taxonomy: The brachyuran family Grapsi- men. They have a large plate-like carapace dae, the shore , was a very large fami- dorsally, beneath which are five pairs of tho- ly with several subfamilies and little taxo- racic appendages (see chelipeds and pereo- nomic scrutiny, until recently. Based on mo- pods) and three pairs of maxillipeds (see lecular and morphological evidence, authors mouthparts). The abdomen and associated (von Sternberg and Cumberlidge 2000; appendages are reduced and folded ventrally Schubart et al. 2000; de Grave et al. 2009; (Decapoda, Kuris et al. 2007). Schubart 2011) elevated all grapsid subfam- Cephalothorax: ilies to family level, reducing the number of Eyes: Eyestalks and orbits moderately species formally within the . Re- sized (Rathbun 1918) and eyes at antero- cent molecular evidence has placed Hemi- lateral angle (Fig. 2). species within the Varunidae, but Antenna: this is currently debated where some au- Mouthparts: The mouth of decapod thors still refer to them as members of the comprises six pairs of appendag- Grapsidae sensu lato (Ng et al. 2008; Wick- es including one pair of mandibles (on either sten 2012) and others have adopted the side of the mouth), two pairs of maxillae and new familial designation (e.g. Kuris et al. three pairs of maxillipeds. The maxillae and 2007). Besides the higher taxonomic classi- maxillipeds attach posterior to the mouth and fications, the known specific synonym for H. extend to cover the mandibles (Ruppert et al. oregonensis is Pseudograpsus oregonensis 2004). (Wicksten 2012), which is not currently Carapace: Rectangular or square in used. shape and wider than long with rounded ante- ro-lateral margins. Carapace surface is Description smooth and bears three teeth (two lateral that Size: Carapace 34.7 mm in width and 28.4 are posterior to postorbital) (Wicksten 2012) mm in length (Rathbun 1918; Wicksten on antero-lateral margin, no transverse lines 2012) (Fig. 1). The carapace of reproduc- (Fig. 1). tive individuals measures approximately 50 Frontal Area: Less than half the width mm (Puls 2001). of the carapace with two prominent frontal Color: Dull brownish green, gray to uniform lobes and deep median sinus (Wicksten light gray or muddy yellow with no red spots 2012). Frontal margin without teeth on chelipeds (compare H. nudus, Plate 21, (, Kuris et al. 2007). Kozloff 1993; Kuris et al. 2007). Nearly Teeth: Two lateral carapace teeth, with white or yellow forms of both Hemigrapsus deep sinuses, below outer orbital tooth (Fig. species have been reported (Ricketts and 2). Calvin 1971; Wicksten 2012). Pereopods: More or less hairy General Morphology: The body of decapod (compare to H. nudus) (Fig. 1). crustaceans can be divided into the cepha- Chelipeds: Stout and equal or almost lothorax (fused head and thorax) and abdo-

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. . 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.

equal in size. Dactyls hollowed in shallow sion, 2) the lateral spines of H. oregonensis groove and male with mat of fine hair on are sharp and distinctly separated from the propodus. side but H. nudus spines are not, 3) The dac- Abdomen (Pleon): Females with wide ab- tyls of walking legs 1–3 are long in H. ore- domen and male H. oregonensis have nar- gonensis and short in H. nudus and 4) the row abdomens that exposes the sternum at dactyl of the fourth walking leg is round in H. the base (see Sexual Dimorphism, Fig. 3). oregonensis and flat in H. nudus (Kuris et al. Telson & Uropods: 2007). The final varunid crab that occurs lo- Sexual Dimorphism: Male and female cally is the introduced , brachyuran crabs are easily differentiable. sinensis, but this species is very The most conspicuous feature, the abdo- large and easily differentiable from either men, is narrow and triangular in males while Hemigrapsus species. it is wide and flap-like in females (Brachyura, crassipes, a member of Kuris et al. 2007). Male H. oregonensis the Grapsidae, is a dark green crab with many have a narrow abdomen that exposes the transverse dark red striations on its legs and sternum (Fig. 3) and hairy chelipeds. Fe- carapace (H. oregonensis is smooth), its males have a wide abdomen and ho hairy frontal margin is straight and it has one lateral patch on palm (only a few bristles). tooth, not two (Symons 1964). The only other locally occurring grapsid crab, cya- Possible Misidentifications neus, is a pelagic species that is only found Hemigrapsus species were formally washed ashore on drift logs with gooseneck members of the Grapsidae, a family charac- barnacles (Kuris et al. 2007). Rhithropanope- terized by the carpus of the third maxilliped us harrisii, an introduced xanthid not articulating near the anterior merus an- (Panopeidae) mud crab, is sometimes found gle and by lateral mouth margins that are with H. oregonensis. It has a slightly conver- parallel or convergent (Wicksten 2012). The gent sides, strong dorsal ridges on its cara- Hemigrapsus may now be a member pace and three sharp carapace teeth. of the family Varunidae (see ) characterized by chelae morphology, gaping Ecological Information third maxillipeds and setose walking legs Range: Type locality is Puget Sound, Wash- (Ng et al. 2008). Two Hemigrapsus species ington. Known range includes Alaska to Baja occur locally, H. oregonensis and H. nudus. California, Mexico (Wicksten 2012). Hemigrapsus nudus, the , Local Distribution: Common in many Ore- is larger than H. oregonensis, is “naked” (i.e. gon bays including Yaquina, Siletz, Tillamook, not hairy) on its walking legs and has cheli- Netarts, Coos and Coquille (Ricketts and Cal- peds with conspicuous red spots. Hemi- vin 1971). grapsus nudus lives mostly on the rocky Habitat: Quiet water, rocky habitats within es- open coast, but is also found in salt marshes tuaries, gravel shores but prefers muddy habi- (Knudsen 1964). Hemigrapsus oregonensis tats (Ricketts and Calvin 1971) and salt has been called a small, bleached edition of marshes. On muddy bottoms of estuaries H. nudus (Ricketts and Calvin 1971). The and on eelgrass and amongst Enteromorpha. following features are particularly useful in Also in muddy spots on the open rocky coast. differentiating the two Hemigrapsus species: The two Hemigrapsus species can co-occur, 1) H. oregonensis has a marked frontal but one usually finds one or the other and H. notch where H. nudus has a shallow depres- oregonensis prefers quieter water than does

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]

H. nudus (Kozloff 1993). May, while in Puget Sound, Washington, they Salinity: Hemigrapsus oregonensis toler- are ovigerous earlier (in Feb–April) and hatch ates salinity ranging from 17.5–31.6 (San between May and July. Broods include 800– Francisco, California), likes freshwater 11,000 embryos and 70% of females produce seeps (Garth and Abbott 1980) and cannot a second brood that will hatch in September. tolerate much desiccation. Embryos change color as they mature from Temperature: Small most tolerant white to purple to brown before they hatch at to temperature extremes (Todd and Dehnel which time they are approximately 300–400 1960). µm in diameter (Jaffe et al. 1987). In the lab, Tidal Level: Found at very high and very hatching occurs after 44 days (10–12˚C, Jaffe low tide levels, but usually lower intertidal et al. 1987). The reproduction and life-cycle than H. nudus (Todd and Dehnel 1960). In- of C. epialti is dependent on and corresponds dividuals can be found at higher tidal reach- to that of its host species. However, this ne- es of the mudflats (Ricketts and Calvin mertean is not host specific (unlike Carci- 1971) and mid to low intertidal of bays as nonemertes errans on Cancer magister) and well as sublittorally (Kuris et al. 2007). occurs amongst egg masses of other species Associates: Hemigrapsus oregonensis has including H. nudus, many associates. In gravel, isopods Idotea (Roe et al. 2007). Interestingly, it may be and Gnorimosphaeroma, and occasionally more common on H. oregonensis than P. H. nudus (Kozloff 1993). Alga Ulva producta, for which it was described (Kuris (sublittorally), and pickleweed, Salicornia (in 1993; Kuris et al. 2007). marshes) (Kuris et al. 2007; Wicksten 2012). Larva: Larval development in H. oregonensis The parasitic castrating isopod, Portunion proceeds via a series of zoea (five total) and conformis, is sometimes within the pe- megalopae stages, each marked by a molt. rivisceral cavity of H. oregonensis (Garth The zoea are planktotrophic and have large and Abbott 1980) with infection rates up to compound eyes and four spines: one each 40% (Jaffe et al. 1987; Kuris et al. 2007). dorsal and rostral and two lateral (see Fig. 32, Hemigrapsus oregonensis, H. nudus and P. Puls 2001; Fig. 54.5, Martin 2014). The ros- crassipes can all be host to the nemertean trum and dorsal spines are of equal length egg predator, Carcinonemertes epialti, and the two lateral spines are shorter (Puls which can negatively impact brood mortality 2001). The first zoea has exospines on the in these species (Shields and Kuris 1988). telson, is approximately 1.1 mm (measured These three species can also serve as inter- from tip of rostrum to tip of telson) and has mediate hosts for a variety of parasites in- lateral knobs on the second segment only, cluding trematode metacercariae, larval tryp- where H. nudus has lateral knobs on the sec- anorhynch tapeworms, as well as Poly- ond and third segments (Puls 2001). The lar- morphus acanthocephalan and nematode vae of H. oregonensis are also a bit smaller (Ascarophis) larvae (Kuris et al. 2007). and more slender than that of the closely re- Abundance: In great numbers, benthically, lated H. nudus (Jaffe et al. 1987). The zoea in estuaries and usually common on gravelly of Hemigrapsus species and P. crassipes can substrates (Wicksten 2012). be differentiated by body and eye size (Schlotterbeck 1976). Hemigrapsus ore- Life-History Information gonensis megalopae are rectangular and can Reproduction: In Vancouver, Canada, fe- be recognized by a posterior telson without males are ovigerous in March and hatch in setae (other than uropod setae) and a cara-

Hiebert, T.C. 2015. Hemigrapsus oregonensis. 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.

pace that is 1.4–1.7 mm in length and 1.1– R. H. Morris, D. P. Abbott, and E. C. 1.3 mm in width. The first in-star stage is Haderlie (eds.). Stanford University Press, reached after approximately 4–5 weeks Stanford, CA. (Puls 2001). 3. KNUDSEN, J. W. 1964. Observations of Juvenile: Very small animals have a the reproductive cycles and ecology of the marked frontal notch and sharp lateral common Brachyura and crablike Anomura spines and long dactyls on walking legs (1– of Puget Sound, Washington. Pacific Sci- 3) (Smith and Carlton 1975). Juveniles in ence. 18:3-33. both sexes have narrow abdomens. 4. KOZLOFF, E. N. 1993. Seashore life of Longevity: the northern Pacific coast: an illustrated Growth Rate: Growth occurs in conjunction Guide to northern California, Oregon, with molting. In pre-molting periods the epi- Washington, and British Columbia. Univer- dermis separates from the old cuticle and a sity of Washington Press, Seattle, WA. dramatic increase in epidermal cell growth 5. KURIS, A. M. 1993. Life cycles of nemer- occurs. Post-molt individuals will have soft teans that are symbiotic egg predators of shells until a thin membranous layer is de- decapod crustacea: adaptations to host posited and the cuticle gradually hard- life histories. Hydrobiologia. 266:1-14. ens. During a molt decapods have the abil- 6. KURIS, A. M., P. S. SADEGHIAN, J. T. ity to regenerate limbs that were previously CARLTON, and E. CAMPOS. 2007. De- autonomized (Kuris et al. 2007). capoda, p. 632-656. In: The Light and Food: Primarily an herbivore, scraping Ulva Smith manual: intertidal invertebrates from or Enteromorpha off rocks, H. oregonensis central California to Oregon. J. T. Carlton uses tactile, visual and chemical sense to (ed.). University of California Press, Berke- find food (Knudsen 1964; Kozloff 1993). ley, CA. Predators: Birds (e.g. willet, Rathbun 1918). 7. MARTIN, J. W. 2014. Brachyura, p. 295- Behavior: A moderately active species that 310. In: Atlas of larvae. J. W. is a good digger and probably nocturnal Martin, J. Olesen, and J. T. Høeg (eds.). (Knudsen 1964; Garth and Abbott 1980; Ku- Johns Hopkins University Press, Balti- ris et al. 2007). more, MD. 8. NG, P. K. L., D. GUINOT, and P. J. F. DA- Bibliography VIE. 2008. Systema brachyurorum: Part I. 1. DE GRAVE, S., N. D. PENTCHEFF, S. Annotated checklist of the extant Brachy- T. AHYONG, T. CHAN, K. A. CRAN- uran crabs of the world. Raffles Bulletin of DALL, P. C. DWORSCHAK, D. L. FELD- Zoology Supplement. 17:1-286. ER, R. M. FELDMANN, C. FRANSEN, L. 9. NYBLADE, C. F. 1987. Phylum or Subphy- Y. D. GOULDING, R. LEMAITRE, M. E. lum Crustacea, Class Malacostraca, Order Y. LOW, J. W. MARTIN, P. K. L. NG, C. Decapoda, Anomura, p. 441-450. In: Re- E. SCHWEITZER, S. H. TAN, D. production and development of marine in- TSHUDY, and R. WETZER. 2009. A vertebrates of the northern Pacific coast. classification of living and fossil genera of M. F. Strathmann (ed.). University of decapod crustaceans. Raffles Bulletin of Washington Press, Seattle, WA. Zoology:1-109. 10. PULS, A. L. 2001. Arthropoda: Decapoda, 2. GARTH, J. S., and D. P. ABBOTT. 1980. p. 179-250. In: Identification guide to larval Brachyura: The true crabs, p. 594-630. marine invertebrates of the Pacific North- In: Intertidal invertebrates of California. west. A. Shanks (ed.). Oregon State Uni-

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]

versity Press, Corvallis, OR. the central California coast. University of 11. RATHBUN, M. J. 1918. The grapsoid California Press, Berkeley. crabs of America. Bulletin of the United 20. SYMONS, P. E. K. 1964. Behavioral re- States Natural Museum. 97:128-145. sponses of the crab Hemigrapsus ore- 12. RICKETTS, E. F., and J. CALVIN. 1971. gonensis to temperature, diurnal light vari- Between Pacific tides. Stanford Universi- ation, and food stimuli. Ecology. 45:580- ty Press, Stanford, California. 591. 13. ROE, P., J. L. NORENBURG, and S. 21. TODD, M., and P. A. DEHNEL. 1960. Ef- MASLAKOVA. 2007. Nemertea, p. 221- fect of temperature and salinity on heat 233. In: Light and Smith manual: intertid- tolerance in two grapsoid crabs, Hemi- al invertebrates from central California to grapsus nudus and Hemigrapsus ore- Oregon. J. T. Carlton (ed.). University of gonensis. Biological Bulletin. 118:150-172. California Press, Berkeley, CA. 22. VON STERNBERG, R., and N. CUMBER- 14. RUPPERT, E. E., R. S. FOX, and R. D. LIDGE. 1998. Taxic relationships within BARNES. 2004. Invertebrate zoology: a the Grapsidae (MacLeay, 1838) functional evolutionary approach. Thom- (Crustacea: Decapoda: Eubrachyura). son Brooks/Cole, Belmont, CA. Journal of Comparative Biology. 3:115- 15. SCHLOTTERBECK, R. E. 1976. Larval 136. development of the lined shore crab, 23. WICKSTEN, M. K. 2011. Decapod crusta- Pachygrapsus crassipes Randall, 1840. cea of the Californian and Oregonian Zoo- (Decapod: Brachyura: Grapsidae) reared geographic Provinces. http:// in the laboratory. Crustaceana. 30:184- escholarship.org/uc/item/7sk9t2dz. 200. Scripps Institution of Oceanography, UC 16. SCHUBART, C. D. 2011. Reconstruction San Diego, San Diego, CA. of phylogenetic relationships within Grap- Updated 2015 sidae (Crustacea: Brachyura) and com- T.C. Hiebert parison of trans-isthmian versus amphi- atlantic gene flow based on mtDNA. Zo- ologischer Anzeiger. 250:472-478. 17. SCHUBART, C. D., J. A. CUESTA, R. DIESEL, and D. L. FELDER. 2000. Mo- lecular phylogeny, taxonomy, and evolu- tion of non-marine lineages within the American grapsoid crabs (Crustacea: Brachyura). Molecular Phylogenetics and Evolution. 15:179-190. 18. SHIELDS, J. D., and A. M. KURIS. 1988. Temporal variation in abundance of the egg predator Carcinonemertes epialti (Nemertea) and its effect on egg mortali- ty of its host, the shore crab, Hemigrap- sus oregonensis. Hydrobiologia. 156:31- 38. 19. SMITH, R. I., and J. T. CARLTON. 1975. Light's manual: intertidal invertebrates of

Hiebert, T.C. 2015. Hemigrapsus oregonensis. 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.