Cancer Oregonensis Class: Multicrustacea, Malacostraca, Eumalacostraca

Phylum: Arthropoda, Crustacea

Cancer oregonensis Class: Multicrustacea, Malacostraca, Eumalacostraca

Order: Eucarida, Decapoda, Pleocyemata, Brachyura, The Oregon Cancer crab Eubrachyura, Heterotremata Family: Cancroidea, Cancridae

Taxonomy: Several synonyms are listed for appendages are reduced and folded ventrally the species Cancer oregonensis (e.g. (Decapoda, Kuris et al. 2007). Platycarcinus recurvidens, Trichocarcinus Cephalothorax: walkeri, Trichocera oregonensis), but the Eyes: Eye stocks short. most recent taxonomic debate involves the Antenna: Antennules folded length- placement of this species in the recently ele- wise (Fig. 3) bear short, hairy flagella. vated genus, Glebocarcinus (Schweitzer and Mouthparts: The mouth of decapod Feldmann 2000). Molecular work does not crustaceans is comprised of six pairs of ap- always support the monophyly of cancrid pendages including one pair of mandibles (on genera (Harrison and Crespi 1999) and either side of the mouth), two pairs of maxillae although many researchers have switched to and three pairs of maxillipeds. The maxillae the name Glebocarcinus oregonensis (e.g. and maxillipeds attach posterior to the mouth Wicksten 2011), we follow the most current and extend to cover it and the mandibles local intertidal guide that retains the name (Ruppert et al. 2004). The outer maxillipeds Cancer oregonensis (Kuris et al. 2007). in C. oregonensis have with merus at antero- external angle (Fig. 2). Description Carapace: Broadly oval, subelliptical Size: Individuals are usually not over 40 mm (Rathbun 1930), widest at teeth 7–8 and aer- wide (Kozloff 1993). Large females are 47.1 olated. Anterior-lateral and posterior-lateral mm wide and 36.5 mm long (Rathbun 1930). margins do not form a distinct angle (C. ore- The illustrated (Fig. 1) specimen is 15 mm gonensis, Rathbun 1930; Garth and Abbott wide and 11 mm long. 1980). Postero-lateral margin unbroken, Color: Carapace reddish dorsally, some- entire and without teeth. Antero-lateral and times red, orange or yellow pigment spots or postero-lateral margins meet without strong bands, and flesh-colored ventrally. Walking angle (Fig. 1). A characteristic that separates legs (perepods) with dark red to black the (proposed) genus Gleobcarcinus from cheliped tips and can have bands of light other cancrid genera is a rounded carapace color or red spots. There is considerable with length ¾ maximum width, as seen in C. variation in color from yellow to orange with oregonensis (Schweitzer and Feldmann 2000; carapaces that are sometimes gray (Jensen Schram and Ng 2012). 1995; Wicksten 2011). Frontal Area: Wide frontal area (about General Morphology: The body of decapod 1/2 width of carapace). Five truncate frontal crustaceans can be divided into the cepha- teeth extend slightly beyond outer orbital an- lothorax (fused head and thorax) and abdo- gles. Three central teeth lobed (C. oregonen- men. They have a large plate-like carapace sis, Rathbun 1930). Outer pair of teeth form dorsally, beneath which are five pairs of tho- inner orbital angles (Fig. 3). racic appendages (see chelipeds and pere- Teeth: 12–13 antero-lateral teeth, of opods) and three pairs of maxillipeds (see which the first nine are prominent, equal, mouthparts). The abdomen and associated

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. and A. Burgess. 2015. Cancer 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 Biolo- gy, Charleston, OR.

large and forward curving. Teeth 3–9 have oregonensis is the only member of the genus spines, teeth 10–13 are small, obscure or with a distinctly elliptical carapace, without absent. distinct angle at the posterior-anterior margin. Pereopods: Walking legs hairy, light It is smaller than most of the other adult colored and with darkly pigmented dactyls. Cancer species, but can be confused with Chelipeds: Dark nearly to tips (Fig. their juveniles, which occur only seasonally, 4), carpus (wrist) tuberculate above, short not all year, as will C. oregonensis. The key spine at inner angle with tooth below. Hand characteristic is the rounded, not angled (propodus) thick and high, with two rows of carapace shape. Cancer oregonensis tubercules above and five granulate lines on occupies a very particular niche: in the under- outer surface (Fig. 4). Chelae rougher in rock habitat, often found nestled in a well- females than in males (Rathbun 1930). fitting discarded mollusk or barnacle shell Abdomen (Pleon): Abdomen narrow in (Garth and Abbott 1980; Kozloff 1993). male, broad in female (e.g. see Cancer There are eight Cancer species known magister, Fig. 3). locally (Kuris et al. 2007) and three of those Telson & Uropods: are larger than C. oregonensis in their adult Sexual Dimorphism: Male and female form including, C. magister (adults at least 30 brachyuran crabs are easily differentiable. mm in width), C. productus (adults over 20 The most conspicuous feature, the abdo- mm in width) and C. antennarius (adults typi- men, is narrow and triangular in males while cally 100 mm in width). Cancer productus it is wide and flap-like in females. Addition- and C. magister have 10 antero-lateral teeth ally, males have one large chelae and two and five subequal frontal teeth (Kuris et al. pleopod pairs specialized for copulation, 2007). The carapace of C. magister is widest however, the third and fourth pleopods are at the tenth tooth, is more subtly pigmented absent. Females, on the other hand, have and does not have black tipped dactyls seen all four pleopod pairs, each with long setae in C. productus (Wicksten 2011). The two for egg attachment (Brachyura, Kuris et al. species are often collected together in crab 2007). Female C. oregonensis often have a pots. Cancer antennarius, like C. productus, more uneven and lumpy textured carapace is dark red with spots ventrally and with black (sometimes with high, flattened elevations) tipped chelae. However, the carapace width and rougher chelae than males. in C. antennarius is widest at the eighth tooth and there are a total of 11 antero-lateral teeth Possible Misidentifications (Schmitt 1921; Kuris et al. 2007; Wicksten According to some authors, the ge- 2011). nus Cancer comprises 23 species (Harrison The remaining four species tend to be and Crespi 1999 but see Schweitzer and smaller and have nine antero-lateral teeth Feldmann 2000). This genus is (sometimes ten in older specimens, Wicksten differentiated from other brachyuran genera 2011). Cancer branneri is a small species (35 by the broadly oval carapace, presence of mm) that is rare intertidally and recognizable five frontal teeth and antennules that fold by cheliped dactyls that are long, straight, back over carapace. Characters unique to black and spiny. Cancer gracilis (27 mm) has Cancer oregonensis include 12–13 antero- white-tipped cheliped dactyls and C. jordani lateral teeth, carapace widest at 7–8 tooth, (25 mm) has a hairy carapace and sharp cur- red color, black-tipped cheliped dactyls and ving teeth. Cancer anthonyi, the yellow rock small size (Kuris et al. 2007). Cancer crab, is larger than the previous three at 52

mm and has black-tipped cheliped dactyls molt, male C. oregonensis clasp females sev- (Kuris et al. 2007; Wicksten 2011). Popula- eral days prior to molting and copulation takes tions of C. productus, C. anthonyi (southern place after molting occurs. Fertilization is in- California) and C. magister support commer- ternal and occurs after molting and egg cial fisheries (Kuris et al. 2007). deposition occurs months later, November– March (December, Coos Bay) (Garth and Ecological Information Abbott 1980; Jaffe et al. 1987). Eggs are Range: Type locality is Puget Sound, Wash- bright orange and approximately 400 µm in ington. Known range includes Aleutian diameter and each brood contains Islands in Alaska to Lower California approximately 20,500 eggs (Knudsen 1964). (Schmitt 1921; Ricketts and Calvin 1971; A second brood is sometimes produced after Wicksten 2011). Rare south of Oregon the first hatches (Jaffe et al. 1987). Eyespots (Kuris et al. 2007). and chromatophores are easily visible in Local Distribution: Coos Bay distribution at advanced embryos (Jaffe et al. 1987; Kuris et Fossil and Pigeon points. al. 2007). Habitat: Rocky intertidal and subtidal areas Larva: Larval development proceeds via a of quiet bays, tidepools and well embedded series of zoea (five total, telson with single rock and mud. Likes closely fitting shells, lateral spine at each fork, Lough 1975) and crannies. megalopae stages, each marked by a molt. Salinity: Found at lower (saltier) end of Cancer oregonensis zoea are planktotrophic bays. and have large compound eyes and four Temperature: A cold and temperate water spines: one each dorsal and rostral and two dweller (by geographical range). lateral (Lough 1975; see Cancer spp., Fig. 31, Tidal Level: Low intertidal to 435 m Puls 2001; Martin 2014). Larval size (Rathbun 1930; Wicksten 2011). (measured from tip of rostrum to tip of telson) Associates: In the under-rock low intertidal proceeds from 1.6 mm (Zoea I) to 2.3 mm of bays associates include burrowing clams (Zoea V) (Puls 2001). Megalopae are of simi- (Pholadidae), terebellid polychaete Thelepus lar size to C. productus, at 3.4 mm (from ros- and its associate Halosydna. Subtidally, the trum tip to posterior carapace) and total larval large barnacle Balanus nubilis, whose dis- duration is unknown (Puls 2001). The zoea carded shell is often home to C. and megalopae of cancrid species are difficult oregonensis. A parasitic barnacle to distinguish. The megalopae of C. (Rhizocephalan) becomes prevalent in oregonensis and C. productus were described Alaskan animals (Ricketts and Calvin 1971). by DeBrosse et al. 1990 (see Fig. 1-2, 3-4, Abundance: Occurs commonly within its DeBrosse et al. 1990). habitat. Juvenile: Very much like adults (Schmitt Life-History Information 1921). Reproduction: All decapod crustacean fe- Longevity: males attach recently laid gelatinous egg Growth Rate: Growth occurs in conjunction masses to their pleopods. The outer em- with molting. In pre-molting periods the epi- bryo membrane thickens and a strand devel- dermis separates from the old cuticle and a ops that attaches each embryo to pleopod dramatic increase in epidermal cell growth oc- setae (Decapoda, Kuris et al. 2007). Mating curs. Post-molt individuals will have soft occurs from April–June (Puget Sound, shells until a thin membranous layer is depos- Washington), when the female is about to ited and the cuticle gradually hardens. During

a molt decapods have the ability to regener- 7. KOZLOFF, E. N. 1993. Seashore life of ate limbs that were previously autotomized the northern Pacific coast: an illustrated (Kuris et al. 2007). guide to northern California, Oregon, Food: Predator and scavenger on other Washington, and British Columbia. Univer- small invertebrates, especially barnacles sity of Washington Press, Seattle, WA. (Jaffe et al. 1987). 8. KURIS, A. M., P. S. SADEGHIAN, J. T. Predators: CARLTON, and E. CAMPOS. 2007. De- Behavior: Reclusive. capoda, p. 632-656. In: The Light and Smith manual: intertidal invertebrates from Bibliography central California to Oregon. J. T. Carlton 1. DEBROSSE, G. A., A. J. BALDINGER, (ed.). University of California Press, Berke- and P. A. MCLAUGHLIN. 1990. A Com- ley, CA. parative study of the megalopal stages of 9. LOUGH, R. G. 1975. Dynamics of crab Cancer oregonensis Dana and Cancer larvae (Anomura: Brachyura) off the cen- productus Randall (Decapoda: Brachy- tral Oregon coast, 1969-1971. Ph.D. Ore- ura: Cancridae) for the northeastern Pa- gon State University, Corvallis, OR. cific. Fishery Bulletin. 88:39-49. 10. MARTIN, J. W. 2014. Brachyura, p. 295- 2. GARTH, J. S., and D. P. ABBOTT. 1980. 310. In: Atlas of crustacean larvae. J. W. Brachyura: the true crabs, p. 594-630. In: Martin, J. Olesen, and J. T. Høeg (eds.). Intertidal invertebrates of California. R. H. Johns Hopkins University Press, Balti- Morris, D. P. Abbott, and E. C. Haderlie more, MD. (eds.). Stanford University Press, Stan- 11. PULS, A. L. 2001. Arthropoda: Decapoda, ford, CA. p. 179-250. In: Identification guide to larval 3. HARRISON, M. K., and B. J. CRESPI. marine invertebrates of the Pacific North- 1999. Phylogenetics of Cancer crabs west. A. Shanks (ed.). Oregon State Uni- (Crustacea : Decapoda : Brachyura). Mo- versity Press, Corvallis, OR. lecular Phylogenetics and Evolution. 12. RATHBUN, M. J. 1930. The Cancroid 12:186-199. crabs of America of the families Euryali- 4. JAFFE, L. A., C. F. NYBLADE, R. B. dae, Portunidae, Atelecyclidae, Cancridae FORWARD, and S. SULKIN. 1987. Phy- and Xanthidae. U.S. Government Printing lum or subphylum Crustacea, class Mala- Office, Washington, D.C. costraca, order Decapoda, Brachyura, p. 13. RICKETTS, E. F., and J. CALVIN. 1971. 451-475. In: Reproduction and develop- Between Pacific tides. Stanford University ment of marine invertebrates of the Press, Stanford, California. northern Pacific coast. M. F. Strathmann 14. RUPPERT, E. E., R. S. FOX, and R. D. (ed.). University of Washington Press, BARNES. 2004. Invertebrate zoology: a Seattle, WA. functional evolutionary approach. Thom- 5. JENSEN, G. C. 1995. Pacific coast crabs son Brooks/Cole, Belmont, CA. and shrimps. Sea Challengers, Monte- 15. SCHMITT, W. L. 1921. The marine deca- rey, CA. pod crustacea of California. University of 6. KNUDSEN, J. W. 1964. Observations of California Publications in Zoology. 23:1- the reproductive cycles and ecology of 470. the common Brachyura and crablike 16. SCHRAM, F. R., and P. K. L. NG. 2012. Anomura of Puget Sound, Washington. What is Cancer? Journal of Crustacean Pacific Science. 18:3-33. Biology. 32:665-672.

17. SCHWEITZER, C. E., and R. M. FELD- MANN. 2000. Re-evaluation of the Can- cridae Latreille, 1802 (Decapoda: Brach- yura) including three new genera and three new species. Contributions to Zool- ogy. 69:223-250. 18. WICKSTEN, M. K. 2011. Decapod crustacea of the Californian and Oregonian Zoogeographic Provinces. http:// escholarship.org/uc/item/7sk9t2dz. Scripps Institution of Oceanography, UC San Diego, San Diego, CA. Updated 2015 T.C. Hiebert and A. Burgess