The Shallow Water Anomuran Crab Fauna Of Southwestern Baja-California Mexico

Abstract

Thirty-five species of anomuran crabs are reported from the 1964 "Mag Bay" Expedition, 19 orv\hich are new records for the outer coast of southern Baja California, Mexico. A checklist and keys are appended for the 52 species of Anomura nov\ known to inhabit this area. RESUMEN.—Durante la Expedicion "'Mag Bay" en 1964, se observaron treinta y cinco especies de cangrejos anomuros, diez y nueve de ellas encontradas por primera vez, en las costas occidentales de la zona meridional de Baja California. Mexico. Se incluye una lista y las claves correspondientes para las 52 especies de Anomuros observados hasta la fecha en aquellas regiones. The purpose of the "Mag Bay" Expedition of 1964 was to study the maritime biota along the coast of Baja California, Mexico, from Punta San Eugenio (Punta Eugenia) to the lower entrance of Bahfa Magadalena (Figs. 1, 2). Dr. Carl L. Hubbs, Scripps Institution of Oceanography, was the originator and leader of the expedition, which was supported by the Office of Naval Research. The scientific party was divided into three teams: Team 1, aboard the R/V HORIZON, was responsible for sampling in deep water; Team 2, in small craft, worked in the mangrove-estuarine environment; Team 3, aboard the Scripps vessel T-441, was responsible for "on site" fish poisonings, invertebrate and algal collecting, and otter trawling along the 20and 40 m depth contours in the area of study. Two of the authors (TSH and TBS) were members of Team 2, where SCUBAwas used in depths of one to 30 meters. A concerted effort was made to collect decapod crustaceans and echinoderms, as well as fish. The specimens were returned to the T-441, where they were kept alive until color notes and tentative identifications could be recorded. At the conclusion of the cruise, the anomuran crabs were forwarded to the Allan Hancock Foundation for study by the senior author (JH). Thirty-five species of Anomura were collected, of which 19 constitute new records for the outer coast of southern Baja California (Punta San Eugenio and southward) within the 40 m contour. A checklist and keys to all species known to fall within these geographical and bathymetrical limits are appended. This report is a Contribution from the Allan Hancock Foundation, no. 339 , supported by NSF Grant GB-2039, and a Contribution from the Scripps Institution of Oceanography, supported by NSFGrant GB2312 (to D. L. Fox). HISTORICAL RESUME The following anomuran crabs are presently known from the region under consideration: Miinida mexicana (Benedict, 1902), Dardaniis sinistripes (Rathbun, 1910), Pleuroncodes planipes, and Emerita analoga (Schmitt, 1921). In addition, Glassell (1936) reported on several porcellanids which he collected at Bahfa Magdalena. These included Petrolisthes hirtipes (Lockington), and the new species Orthochela pumila. Pisosoma erosa { = Megalobrachium erosum), and Porcellana magdalenensis ( = Pisidia magdalenensis). He also treated the porcellanid and hermit crabs from the Templeton Crocker Expedition of SAN DIEGO SOC. NAT. HIST.. TRANS. 16 (2): 13-32, 4 JUNE 1970 14 SAN DIEGO SOCIETY OF NATURALHISTORY VOL. 16 Figure 1. Map of Baja California, Mexico. Area delimited by the box on the western side of the peninsula is shown enlarged in figure 2. 1936 (Glassell, 1937a, 1937b). However, only one species comes within the scope of the present work, Paguristes bakeri Holmes, which was collected otT Isla Cedros (Glassell, 1937b.) Schmitt (1939) listed "Paguristes species'' from Bahfa Magdalena, a form still awaiting description. To the known fauna Haig (1960) added 16 species of Porcellanidae. 1970 HAIG, HOPKINSANDSCANLAND:ANOMURANCRABS Figure 2. Map of Bahia Magdalena region, Baja California, Mexico. The presence of 19 additional species in this fauna, and the larger number of new records, attests to the effectiveness of SCUBAin an area already well surveyed by dredging and intertidal collecting. ANNOTATEDSPECIES LIST Family COENOBITIDAE Coenobita compressus H. Milne Edwards Cenobita compressa H. Milne Edwards, 1837: 241. Coenobita compressus -.Boone, 1931: 145, text-fig. 3; Holthuis, 1954: 16, text-figs. 4a-b. Recorded Range. —Santa Rosalfa, Golfo de California, to Estrecho de Magallanes. Islas Revillagigedo; Isla del Coco; Archipielago de Galapagos. Material. —Punta Belcher; above high tide at night; 2 Feb. 1964; Id', 2 9. Remarks. —Glassell (1937b: 242-243) stated: "For the most part these terrestrial hermit crabs inhabit the land bordering on the sea. They select heavy shells for their abode. They are, in the main, vegetarians, though they do not limit their diet and may at times act as scavengers, or become carnivorous ... In addition they are good tree climbers." 16 SAN DIEGO SOCIETY OF NATURALHISTORY VOL.16 On Punta Belcher we observed that these animals are nocturnal. A search for their homesites was fruitless, although the crabs "appeared" within 17m of the camp just after dark, and could not be found after daybreak. Probably they had remained inactive in their shells along the upper tide marks during the day, and thus went unnoticed. Six to 10 individuals were observed feeding on dead or molted Pleuroncodes planipes which formed windrows on the beach. The range of this species is extended to the outer Baja California coast, and 300 km north along the outer coast. Family DIOGENIDAE Dardanus sinistripes (Stimpson) Pagurus sinistripes Stimpson, 1858: 22i (nom. nud): \S59: S2. Dardanus sinistripes: Glassell, 1937b: 251. Recorded Range. —Bahfa Magdalena (Rathbun, 1910) and Isla Tiburon, Golfo de California, to Bahfa de Sechura, Peru. Material. —Off Boca de Santo Domingo; otter trawl; 40 m; 27 Jan. 1964; 1 ? . Laguna de Santa Maria: 1.2 m; 29 Jan. 1964; Id". Color. —"In alcohol, the carapace is buff with red markings. The chelipeds, purple and red, with the interior margins of the meri white; the teeth of the fingers white, bordered with yellow. The ambulatory legs are purple, their dactyli with dark brown setae, their meri and carpi blotched on a light ground with red" (Glassell, 1937b). There are two narrow, dark bands, one median and the other proximal, on the eyestalk. Calcinus californiensis Bouvier Calcinus californiensis Bouvier, 1898: 380; Glassell, 1937b: 252. Calcinus californiensis: Chace, 1962: 627, text-figs. 5-6. Recorded Range. —Isla San Jose, Golfo de California, to Acapulco, Me'xico. Isla Clipperton. Material. —Punta Cala; 3 m; 31 Jan. 1964; Id, 1 ?. Roca de la Vela;6 m; 1 Feb. 1964; 2$. Inside Punta Tosca, in lagoon; 5 m; 4 Feb. 1964; 5c^, 2 9. Color. —The coloration of this and allied species, in both live and preserved material, was discussed in some detail by Chace (1962: 628). A broad white band at the base of the cornea and the solid dark color of the dactyls of the walking legs unmistakably identify the above specimens as Calcinus californiensis. Remarks. —The range of this species is extended to the outer Baja California coast, and 300 km north. Aniculus elegans Stimpson Aniculus elegans Stimpson, 1858: 234 («om. nud.): 1859: 83; Boone, 1931: 140, text-fig. 1. Recorded Range. —Golfo de California (exact locality not stated) to Cabo de San Francisco, Ecuador. Material. -Outside Bahfa Magdalena; 18 m; 1 Feb. 1964; 1 juv. Inside Punta Tosca, in lagoon; 5 m; 4 Feb. 1964; 1 ?. Off Punta Redonda; 15 m; 5 Feb. 1964; 6d", 5?. Color. —Carapace red, with a pink area on the posterior part of the shield. Eyestalks tan. Chelipeds pink, with red on the fingers and on the distal half of the chelae. Dactyls of walking legs darkred; other segments pink. A broad, submedian red band on the propodus, a submedian red blotch on the anterior margin of the carpus, and a smaller median blotch on the anterior margin of the merus. Remarks. —Off Punta Redonda these hermits occurred under rocks in aggregates of 1970 HAIG, HOPKINSANDSCANLAND:ANOMURANCRABS 17 five or more. Porcellana paguriconviva Glassell were found in the shells of specimens collected at the same locality, an association that has not been recorded previously. The range of this species is extended to the outer Baja California coast, and 300 km north. Trizopagurus magnificus (Bouvier) Clibanarius magnificus Bouvier, 1898: 378. Clibanarius chetyrkini Boone, 1932: 29, text-fig. 8. Trizopagurus magnificus: Forest, 1952: 4, 12, text-figs. 2, 11, 18. Recorded Range. —Golfo de California (exact locality not stated) to Isla de la Plata, Ecuador. Archipielago de Galapagos. Material. —Roca de la Vela; 6 m; 1 Feb. 1964; 1 ?. Off Punta Redonda; 15 m; 5 Feb. 1964; 15. Color. —The species may be readily identified by the large, irregular pale blotches on a dark background which cover the carapace shield, eyestalks, chelipeds, and walking legs. Remarks. —The range of this species is extended to the outer Baja California coast, and 300 km north. Clibanarius panamensis Stimpson Clibanarius panamensis Stimpson, 1858:235 (nom nud.): 1859: 84; Holthuis, 1954: 23, text-figs. 7-8. Recorded Range. —Santa Rosalfa, Golfo de California, to Isla de la Correa, Peru. Material. —Laguna de Santa Marfa; in +1 mand out of water; 29 Jan. 1964; 8c?, 1 ?. Color. —Hermits of this species may be recognized immediately by the color pattern of the walking legs, which consists of longitudinal dark and light stripes, subequal in width, on each segment. Remarks. —The range of this species is extended to the outer Baja California coast, and 300 km north. Isocheles pilosus (Holmes) Hoiopagurus pilosus Holmes, 1900: 154;Schmitt, 1921: 127, pi. 17 fig. 2; Ricketts and Calvin, 1939: 189, pi. 39 fig. 2. Isocheles pilosus: Forest, 1964: 294. Recorded Range. —Off San Francisco Bay, California, to Estero de Punta Banda, outer Baja California. Material. —Punta Abreojos, Bahfa de Ballenas; +.7 m while wading; 29 Jan. 1964; 1 . 2.5 miles west of Boca de Santo Domingo; 16' otter trawl; 14-20 m; 26 Jan. 1964; Id". Outside Punta Hughes; 20 m; 30 Jan. 1964; 1 2 (juv.). Punta Pequena, Bahfa de San Juanico; 3 m; 8 Feb. 1964; Id", 1 juv. Rem