Phylum: Arthropoda L oxorhynchus crispatus Class: Malacostraca Order: Decapoda Masking Crab, Decorator Crab, Moss Crab Family: Epialtidae

A ribbon worm Natalie Thompson

Taxonomy: Both the genus and species were Ecological Information originally described by Stimpson in 1857. The Range: Eastern Pacific; Alaska to Baja name has not changed since. (WoRMS California (temperate zone) (Hendrickx and 2020). Cervantes 2003, McKittrick 2020). Local Distribution: In kelp forests and rocky Description areas or under man-made structures (Hines Size: Average carapace width for females is 1982). 68 mm and for males is 88 mm. Max Habitat: Prefers kelp and cover to hide carapace width is 100 mm. (Chase & (Hendrickx and Cervantes 2003). Knowlton 2007). Temperature: On average, between 5-15⁰C Color: Legs are red/pink with white patches (Levy 2020). and carapace is brown or green (McKittrick Depth: 0-183 m (McKittrick 2020). 2020). Color is obscured by attachments Associates: Algae, bryozoans, and sponges (Figure 1). are attached to and live on the crab (Wicksten General Morphology: 1978). Body: Pear-shaped body, with a narrow Abundance: Exhibits seasonal variation with anterior end. One anterior pair of claws the greatest abundance in spring (Hines (chelae) and four pairs of legs. (Chase & 1982b). Knowlton 2007). Mouthparts: Row of tactile setae above and Life-History Information below the mouth (Garth & Abbott 1980). Reproduction: Loxorhyncus crispatus Eyes: Two forward-facing compound eyes at copulates with throughout the year, with the most anterior position of the body (Chase multiple partners. Females brood for about 2 & Knowlton 2007). months at a time and carry their fertilized Other species-specific parts: A sharp spine eggs on their pleopodal setae until they hatch. above and next to each eye and rows of (Hines 1982a). The brood size of a larger hooked setae all over the carapace (Wicksten congener, L. grandis, is about 125,000- 1978). 500,000 eggs (Chase and Knowlton 2007). Sexual Dimorphism: Males have a longer Larva: Protozoea for 30 days, develops into carapace and larger chelae (Garth & Abbott three free-swimming planktonic zoeae stages 1980). over 18 days, and metamorphoses into a megalopa for several molts (Hines 1986). Possible Misidentifications Juvenile: Starts with a 1.5 mm wide carapace Loxorhynchus crispatus is often confused with and molts until sexual maturity (Hines 1982). L. grandis, Scyra acutifrons and Chorilia Juveniles ccupy the same regions as adults longipes (McKittrick 2020). The legs in L. (Hendrickx & Cervantes 2003). crispatus are much harrier than in S. Longevity: Unknown for this species. acutifrons and shorter and broader than in C. Growth Rate: Unknown for this species. longipes. The congener L. grandis reaches a Food: Generalist scavenger on invertebrates maximum size close to double that of L. and kelp (Hines 1982). crispatus. Predators: Various fish (sculpins, lingcod, rockfish, etc.), sea otters, and octopuses (Hines 1982). Behavior: Generally slow moving. Attaches other organisms to its setae, though this

A publication of the Oregon Institute of Marine Biology at the University of Oregon. https://oimb.uoregon.edu/oregon-shelf-invertebrates Email corrections to: [email protected] behavior decreases with each successional Brachyura). Bulletin of Marine molt (Wicksten 1979). Science, 39: 444-446. 6. LEVY, R. 2020. Sea Surface Temperature. Bibliography https://neo.sci.gsfc.nasa.gov/view.php 1. CHASE, F., and R. KNOWLTON. ?datasetId=MYD28M 2007. Decapoda (Crustacea). 7. MCKITTRICK, E. 2020. Moss Crab AccessScience, 5:286-296. (Loxorhynchus crispatus). 2. GARTH, J., and D. ABBOTT. https://www.inaturalist.org/observation 1980. Intertidal invertebrates of s/41828362 California. Stanford, California: 8. WICKSTEN, M. 1978. Attachment of Stanford University Press. decorating materials in Loxorhynchus 3. HENDRICKX, M., and J. crispatus (Brachyura: CERVANTES. 2003. A new species of Majidae). Transactions of the Loxorhynchus Stimpson (Decapoda, American Microscopical Society, 97: Majoidea, Pisidae) from the Pacific 217-220. Coast of Mexico. Crustaceana, 76: 9. WICKSTEN, M. 1979. Decorating 103-113. behavior in Loxorhynchus crispatus 4. HINES, A. F. 1982. Coexistence in a Stimpson and Loxorhynchus grandis Kelp Forest: Size, Population Stimpson (Brachyura, Dynamics, and Resource Partitioning Majidae). Crustaceana (Supplement), in a Guild of Spider Crabs (Brachyura, 5: 37-46. Majidae). Ecological Monographs. 10. WoRMS. 2020. Loxorhynchus 52:179-198. crispatus Stimpson, 1857. 5. HINES, A. 1986. Larval patterns in the http://www.marinespecies.org/aphia.p life histories of Brachyuran crabs hp?p=taxdetails&id=441601 (Crustacea, Decapoda,

Figure 1. Loxorhynchus crispatus with light algal cover. A brown algae cluster is highlighted as one of the many decorations on this crab. Photo taken by MacKenna Hainey. Individual collected from 120 m depth near Stonewall Bank off the Oregon coast in September, 2019.

Thompson, N. 2021. Loxorhynchus crispatus. In: Oregon Shelf Invertebrates. C.Q. Plowman and C.M. Young (eds.). Oregon Institute of Marine Biology, Charleston, OR.