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Bijdragen tot de Dierkunde, 54 (2): 220-230—1984 Decapod crustaceans inhabiting live and dead colonies of three species of Acropora in the Roques Archipelago, Venezuela by P. Alejandro Grajal & G. Roger Laughlin Fundación Cientifica Los Roques, Apartado No. 1, Carmelitas, Caracas 1010 A, Venezuela Summary INTRODUCTION A systematic account is given of the decapod crustaceans In recent the of crusta- found in live and dead colonies of three species of the years study decapod associated coral received scleractinian coral Acropora (A. cervicornis, A. palmata, A. ceans to species has collected 9 month in shallow prolifera) , during a period a much attention from marine biogeographers reef flat in the southwestern portion of the Archipelago Los and ecologists. However, because most of the Roques, Venezuela. research has been conducted in the Indo-Paciflc of A total 1900 individuals belonging to 30 species were 1966; Knudsen, 1967; Garth, 1974; found. Some qualitative observations on the ecology, (Patton, feeding, and reproduction of some decapod species are Abele, 1976; Castro, 1976; Glynn, 1980; Abele given. & Patton, 1967; Prahl et al., 1978; Bak & Most of the collected found in the dead species were por- Edwards Robertson, 1980; & Emberton, 1980; tions of the colonies. The crab Domecia acanthophora seems Austin et al., 1980) and in the subtropical to be the only true commensal that depends on the live Atlantic Reed coral tissue. (McCloskey, 1970; et al., 1982), The carideans Latreutes and the there is little information the fucorum Alpheus simus, on occurrence, anomuran the Portunus Pagurus brevidactylus , brachyurans distribution and geographic range of Caribbean vocans and Tetraxanthus bidentatus are reported for the first coral-inhabiting decapods. Patton's (1967) time in Venezuela. work Puerto Rico conducted in was exclusively coral Domecia Resumen on a single associated species, acanthophora, whereas Garth's (1978) and En sistemáticos este trabajo se presentan aspectos y Velez's research involved extensive reef de las de crustáceos (1977) biológicos especies decápodos encon- collections without intensive tradas vivas de colonias de sampling on en partes y muertas tres del coral A. A. coral especies Acropora (A. cervicornis, palmatay pro- specific species. lifera). Estas colonias se colectaron durante de 9 un período The first of series the present paper, a a on meses en un arrecife coralino somero ubicado al extremo ecology of decapod crustaceans inhabiting sur-oeste del Archipiélago de Los Roques, Venezuela. corals in the Los Ro- Se total de 1900 individuos acroporid Archipelago capturaron un pertene- ques, Venezuela, a account cientes a 30 especies. Se dan observaciones sobre la provides systematic alimentación de de ellas. and other relevant information the ecología, y reproducción algunas on decapod Una de las encontró gran parte especies registradas se species found in three species of the coral en la parte muerta de las colonias. Solamente el cangrejo Acropora. Domecia verdadero comensal acanthophora parece ser un que depende del tejido vivo del coral. Los carideos simus el Latreutes fucorum y Alpheus anomurido los Portunus GEOGRAPHIC SETTING AND STUDY Pagurus brevidactylus y branquiuros los vocans y Tetraxanthus bidentatus son primeros registros AREA Venezuela. para The Los is reef Archipelago Roques an insular * located at about 150 km north of the Scientific contribution No. 12 of the Fundación complex Cientîfica Los Roques. north central coast of Venezuela (fig. 1). Downloaded from Brill.com09/25/2021 01:08:50AM via free access BIJDRAGEN TOT DE DIERKUNDE, 54 (2) - 1984 221 The los Fig. 1. Archipiélago de Roques (top) with location of general study area and sampling site (bottom). it forms oval of 36.6 km Roughly, an irregular around a shallow lagoon (depth 1-5 m) in its km X 24.6 on the east-west and north-south centro-meridionalportion. axis, It is formed and The respectively. by 42 islands Archipelago, or more precisely the than 200 sandbanks and reefs distributed submarine more semiatoll, rests on a igneous plateau Downloaded from Brill.com09/25/2021 01:08:50AM via free access 222 - A. GRAJAL P. & R. LAUGHLIN G. DECAPODS IN ACROPORA from 900 1800 measurements were made with a that rises sharply depths of to m. Morphometric calibrated vernier and an ocular micrometer mounted in a The winds and oceanic currents are Wild M8 stereomicroscope. predominantly from the east-northeast. The In Anomura and width Brachyura, carapace (C.W.) climate in the islands could be classified arid- as measured in that and length (C.L.) were and presented humid with annual of while in Natantia an average precipitation order, only carapace length was measured. 300 mm. The symbol 9 ov. refers to ovigerous females, and 9 to The study was conducted on a reef flat at the refers non-ovigerous ones. The abbreviation "juv." to leeward side of a horseshoe-shaped barrier reef juveniles. that connects Dos Mosquises Norte and Dos Mosquises Sur, two nearby keys located at the extreme southwestern corner of the archipelago RESULTS (fig. 1). The reef flat, with a depth of 0.7 to 1.2 m, has an extensive coral cover of Acropora, viz. Before presenting the systematic account of the A. palmata (Lamarck, 1816), A. prolifera (La- decapod crustaceans found in coral colonies of marck, and A. cervicornis 1816), (Lamarck, it is Acropora spp. , important to mentionthat the the corals Porites 1816), although spp., Agaricia plastic bag-enclosing method did not provide and Montastrea annularis spp., (Ellis & Solander, accurate information of the location on the col- 1786), the octocorals Plexaura and Gorgonia spp. of the collected. ony specimens and the spp., hydrozoan Millepora complanata However, the vast majority of them were Lamarck, are also common. Water 1816, observed the on dead portions of the colonies. measured at the dock of the temperatures In fact, a statistical correlation made between Marine Station at Dos less than 1 Mosquises, live coral and the the percent (%) weight of km away from the study site, varied from 25°C number of individuals of the four most in winter (November-February) to 31°C in numerous species found (Domecia acanthophora, from 38.4 summer. Salinity ranged to 39.3°/oo. Mythrax sculptus, Microphris bicornutus, and Thor manningi), showed significant negative relation- for 3 of the A MATERIAL AND METHODS ships species (table I). positive correlation was found only for D. acanthophora. Sampling was conducted from January to November, 1981, and involved the in situ removal of 30 colonies of A of 1900 30 is each The cumulative of number of list individuals from species Acropora species. curve in the decapod species versus number of removed colonies for reported following systematic account: each coral species indicated that 30 colonies was more than enough to collect most decapod species; the in asymptote Suborder NATANTIA the curve was reached at 14 colonies in A. palmata, 26 in A. Section CARIDEA prolifera, and 19 in.A. cervicornis. The selected colonies were Family PALAEMONIDAE of a size which permitted handling and transportation. Genus Periclimenes Costa, 1844 Each colony was covered by a highly resistent polyethylene the of the broken off its bag to prevent escape fauna, at base with hammer and and a a chisel, immediately Periclimenes americanus (Kingsley, 1878) transported to the Marine Laboratory where the colony Refs.: 1951: 19 1965 broken the fauna. Holthuis, 60, pl. figs, a-e; Williams, wascompletely up to remove crustacean 43, fig. 36; Rodriguez, 1980: 90 fig. 27. The live portion of the coral was weighed separately from the dead portion, thus permitting the estimation of Material: 4 19,29 ov., 1 juv. in A. prolifera; 3o\ 59 live coral weight for each colony. Field observations on O", 9 in A. cervicornis. location, feeding and reproduction of conspicuous crusta- ov., juv. ceans were recorded on a submersible note board. Specimens were preserved in a 7% formalin-seawater 2.1 5.9 Size: mm juv. to mm O" C.L. solution with few drops of glycerin, identified,catalogued, Range: Bahamas, North Carolina to Florida, transferred to an alcohol solution and stored in the West Indies. Museum of the Fundación Cientîfica Los Roques at found Caracas, Venezuela. Remarks: This tiny shrimp can be com- Downloaded from Brill.com09/25/2021 01:08:50AM via free access BIJDRAGEN TOT DE DIERKUNDE, 54 (2) - 1984 223 TABLE I Pearson correlation coefficients between percent (%) weight of the live coral colony and number of individuals for the four most numerous species found in colonies of collected from 1981. Acropora spp., January through November, CORAL SPECIES A. cervicornis A. prolifera A. palmata DECAPOD SPECIES Mythrax sculptus r= -0.33 r= -0.42 (*) (n = 443) (1) (« =96) (2) Microphris bicornutus r= -0.37 C) C) (" = 80) (1) Thor manningi O r= -0.48 (*) (« = 153) (2) Domecia acanthophora r= 0.79 r= 0.56 (*) ("=159) (3) (n = 487) (3) (1) =/><0.09 (2) = p<0.01 (3) =/>< 0.005 (*) = The number of individuals was too low for statistical analysis. in shallow in monly waters coral, algae, and Refs.: Holthuis, 1951: 107, pl. 32 figs, d-g, pi. 33; 1980: rocks. Seen on dead portions of the coral. Rodriguez, 93, fig. 28. Material: Ice in A. prolifera. Periclimenes iridescens Lebour, 1949 Size: 1.6 mm C.L. Ref.: Holthuis, 1951: 43, pl. 12, pl. 20 figs, i-j Range: Dry Tortugas, Bermuda, Bahamas, Material: in 2 O* ; 3 9 ov. A. cervicornis. Los Roques; found inside Callyspongia and other in shallow sponges water. 1.7 Size: mm o* to 2.6 mm 9 ov. C.L. Range: Bermuda, Cubagua island, Venezuela; Genus Brachycarpus Bate, 1888 in sand and 100 algae to m. Periclimenes rathbunae Schmitt, 1924 Brachycarpus biunguiculatus (Lucas, 1846) Ref.: Holthuis, 1951: 58, pl. 17 Refs.: Holthuis, 1951: 3, pl. 1; Rodriguez, 1980: 96, fig 30.