Bulletin 292 BREDIN-ARCHBOLD-SMITHSONIAN BIOLOGICAL SURVEY OF DOMINICA The Freshwater and Terrestrial Decapod Crustaceans of the West Indies with Special Reference to Dominica FENNER A. CHACE, JR, AND HORTON H. HOBBS, JR. SMITHSONIAN INSTITUTION UNITED STATES NATIONAL MUSEUM WASHINGTON, D.C. 1969 SMITHSONIAN INSTITUTION MUSEUM O F NATURAL HISTORY UNITED STATES NATIONAL MUSEUM BULLETIN 292 BREDIN-ARCHBOLD-SMITHSONIAN BIOLOGICAL SURVEY OF DOMINICA The Freshwater and Terrestrial Decapod Crustaceans of the West Indies with Special Reference to Dominica FENNER A. CHACE, JR., AND HORTON H. HOBBS, JR. Senior Zoologists, Department of Invertebrate Zoology SMITHSONIAN INSTITUTION PRESS WASHINGTON, D.C., 1969 Publications of the United States National Museum The scientific publications of the United States National Museum include two series, Proceedings of the United States National Museum and United States National Museum Bulletins. In these series are published original articles and monographs dealing with the collections and work of the Museum and setting forth newly acquired facts in the fields of anthropology, biology, geology, history, and technology. Copies of each publication are distributed to libraries and scientific organizations and to specialists and others interested in the various subjects. The Proceedings, begun in 1878, are intended for the publication, in separate form, of shorter papers. These are gathered in volumes, octavo in size, with the publication date of each paper recorded in the table of contents of the volume. In the Bulletin series, the first of which was issued in 1875, appear longer, separate publications consisting of monographs (occasionally in several parts) and volumes in which are collected works on related subjects. Bulletins are either octavo or quarto in size, depending on the needs of the presentation. Since 1902, papers relating to the botanical collections of the Museum have been published in the Bulletin series under the heading Contributions from the United States National Herbarium. This work forms number 292 of the Bulletin series. FRANK A. TAYLOR Director, United States National Museum U.S. GOVERNMENT PRINTING OFFICE WASHINGTON : 1969 For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C., 20402 Price $1.75 (paper cover) Contents Page Introduction 1 Distribution, Relationships, and Origins 13 Ecological Discussion 32 Local Importance of Dominican Species 45 Explanation of Measurements 48 Key to the Families 50 Family Penaeidae 51 Family Atyidae 56 Family Palaemonidae 87 Family Hippolytidae 116 Family Astacidae 117 Family Porcellanidae 121 Family Coenobitidae 123 Family Portunidae 127 Family Pseudothelphusidae 136 Family Trichodactylidae 152 Family Xanthidae 153 Family Grapsidae 156 Family Gecarcinidae 194 Family Ocypodidae 202 Glossary of Terms 224 Literature Cited 228 Index 244 Plates facing p. 42 Introduction The original objective of this study was to describe the abundant but little-known freshwater and terrestrial decapod crustaceans of Dominica. We gradually came to the realization, however, that even the intensive collecting by those who participated in the Bredin- Archbold-Smithsonian Biological Survey of Dominica hardly could be expected to reveal every species that might occur on that island at any time. In order to lend completeness to the Dominican coverage and to make the study useful to biologists interested in the faunas of other islands, we decided to include the 92 species known from all of the West Indies. We have attempted, therefore, to offer a provisional handbook of the decapods that may occur naturally in reduced salini­ ties or above high-tide line on any of the islands from Bermuda to Trinidad and throughout the Caribbean Sea. Previously published studies on the Dominican decapod fauna alone are limited to the brief accounts by Pocock (1889) and G. E. Verrill (1892). The freshwater and terrestrial decapods of eastern tropical America have been treated heretofore as a group in Young (1900), A. E. Verrill (1908), and Holthuis (1959), but only the first of these authors covers the true West Indian region. Certain of the families or higher groups are dealt with in Rathbun (1933), Schmitt (1935), Chace and Holthuis (1948), Hart (1961b), and Hartnoll (1964, 1965), as well as in monographic works of broader geographic coverage such as Rathbun (1905, 1906, 1918, 1930), Bouvier (1925), and Holthuis (1952). In the present review of the fauna, illustrations showing the color patterns—prepared from notes, sketches, and color photographs made in the field—are given for the 29 species represented by adequate ma­ terial in the collections from Dominica, and at least one species of each of the genera not found there is illustrated by an outline drawing. Our intent to figure the male sexual appendages of all species, those from Dominica in somewhat greater detail than the others, was not fully achieved because of the unavailability of adult males of a few of the species. The attempt has been made, but probably not always fulfilled, to fist all synonyms of each species (with type-localities) from the valid post-Linnaean literature, to indicate all combinations under which a species has been mentioned in publications, and to cite all references to Dominican records and to one or more recent works containing 1 2 U.S. NATIONAL MUSEUM BULLETIN 292 figures or more complete species bibliographies. Misidentifications, except when they have become firmly established in the literature, are not listed, and the validity of the synonyms usually has not been verified by the examination of type-material. We should emphasize that the keys and diagnoses apply only to the species covered by the study and often only to adult males; the identi­ fication of female and immature specimens of some species is frequently impossible by current criteria, except by their association with adult males or by similarities in color patterns. The italicized portions of the diagnoses denote those characters that are unique among the species covered of each family. Most of the Dominican shrimps (Macrobrachium, Atya, and Poti- mirim) occur in two "color phases," one in which yellow, tan, and brown predominate and the other characterized by blue, gray, and black. Usually only one of the two is described in detail in the color notes presented here. The vivid colors that are displayed, almost without exception, by recently molted individuals become somewhat dull or obscured as the surface of the exoskeleton is scarred, collects silt, or serves as a substrate for the growth of bacteria, algae, and protozoans. Our color notes were recorded from animals that had not become encrusted with foreign matter. Because of the variability in the actual colors from one individual to another, color charts were not used. Seldom do two specimens have precisely the same color, and occasionally, as in Uca, there is little similarity in details of color pattern. Although the descriptions and illustrations of the color pat­ terns should facilitate the field identification of the species that occur on Dominica, we trust that collectors will soon learn to recognize the relatively constant aspects of the patterns of each species and to use caution in assigning taxonomic importance to differences that may be due to factors such as immaturity, sex, light adaptation, and extra­ neous growth, as well as to intrinsic variation in a species. The distributions cited indicate overall ranges and, in parentheses, the West Indian records. As mentioned below, the island records, especially of widely ranging species that have marine larvae, may be indicative only of the diversity of collecting activities. Our search for island records has not been exhaustive, but a number of new ones have been added from previously unpublished locality records in the Smithsonian collections. The nine species listed below have been recorded, usually only once, from the West Indies, but the records have proved to be, or are believed to be, based on errors of identification or documentation, and they have therefore been excluded from consideration: Cambarellus montezumae (De Saussure, 1857a). Rhoades (1962, p. 72) mis­ takenly indicated that this crayfish had been found "on both sides of the Yucatan Channel." DECAPOD CRUSTACEANS OF THE WEST INDIES 3 Guinotia (Guinotia) reflexifrons (Ortmann, 1897). This species, which was described from the Upper Amazon, was represented in the Berlin Museum by a doubtfully documented specimen from the "Antilles." Guinotia (Neopseudothelphusa) simoni (Rathbun, 1905). The male specimen of this species from the "Antilles" received by the Smithsonian in exchange from the Kiel Museum is correctly identified, but the documentation seems doubtful, for the species is known otherwise only from Venezuela. Sarmatium curvatum (H. Milne Edwards, 1837). It is questionable whether the unique type-specimen of Metagrapsus pectinatus H. Milne Edwards, 1853, a synonym of this otherwise West African grapsid crab, originated in "Martinique." Sesarma (Chiromantes) huzardi (Desmarest, 1825). As indicated by Monod (1956), the documentation of the single specimen of this species from "Barbados" in the Paris Museum needs verification. Uca maracoani (Latreille, 1802-03). As mentioned by Holthuis (1959), "An old record (by Sloane, 1725) of the species from Jamaica is very doubtful." Uca pugilator (Bosc, 1801-02). The single record of this species from Jeremie, Haiti, in the Museum of Comparative Zoology at Harvard is decidedly