REVIEWS

J. FOREST,1995. Crustacea : Révision du genre Trizopagurus Forest, 1952 (), avec l'établissement de deux genres nouveaux. In: A. CROSNIER(ed.), Résultats des Campagnes MUSORSTOM, 13. Mémoires du Muséum national d'Histoire naturelle, Paris, (Zoologie) 163: 9-149. Jacques Forest has produced, once again, an exceptionally detailed revision of a difficult group of hermit crabs. This time it is a study of a group of colorful hermit crabs, some of which exhibit a striking degree of dorsoventral carapace compression that results from living in narrow spaces provided by cone shells. This is a meticulous and abundantly illustrated work that incorporates meristics as well as classical descriptive . It is the culmination of studies that the author began in the early 1950's (Forest, 1952a, b, c), when he proposed the Trizopagurus for a group of hermit crabs variously assigned by earlier carcinologists to three superficially similar genera, Darclanus (as Pagurus sensu Dana), Clibanarius Dana, and Aniculus Dana. This simi- larity had been the source of much confusion, and it is a relief to have it now all sorted out in one publication. It must be mentioned, that a most important step in completing this study was Forest's (1984) important revision of the genus Aniculus which, along with another study (Forest, 1988) redefining the boundaries of the genus Clibanarius, serves as a complement to this revision of Trizopagurus now published in the MUSORSTOM series under the watchful editorial eye of Alain Crosnier. All together, these works are indispensable for those who work with hermit crabs, or for any carcinologist wishing to learn about the Trizopagurus group of the family Diogenidae. This work exemplifies the classical progression of basic systematic research. When Forest pro- posed Trizopagur-usin 1952, he found that it could be divided into three informal groups of species based on the characteristics of the chelipeds and second and third pereopods. At that time only 40 specimens, representing seven species, were available to him from museums around the world. The revision that we are now presented with, is based on examination of 350 specimens accumu- lated with much effort since then, representing 24 species, 14 of which described as new. The fact that Forest's groups have held their validity, after more than tripling the number of species origi- nally assigned to Trizopagurus, is a tribute to the author's knowledge and vision of morphological variations of hermit crabs. The three groups are now elevated to generic status but defined in much greater detail. Three genera are proposed as replacement for his previous informal grouping: Tri- zopagurus, with three species; and two new genera, Ciliopagurus and Str-igopagurus, with 16 and 5 species, respectively. Although the division into three genera is fully justified, it is in the style of this tri-partitioning that I have perhaps the only significant comment to make. One is a bit baffled to find so much detail applied to generic definitions, as it seems unnecessarily restrictive and often repetitious to include a "Diagnosis" and also a lengthy "Definition" section for each genus. Forest's paper includes an introduction, materials and methods, and a detailed chapter devoted to the characters used in the partitioning of Trizopagurus, namely the cephalothoracic shield, thoracic appendages, and organization of pleopods and stridulatory structures. A special section is devoted to the unique stridulatory structures of these hermit crabs, which are used by the author to postulate an evolutionary cline from Trizopagurus via Ciliopagurus to Strigopagurus. Keys are presented for the species of each genus. The treatment of each species includes full synonymies, material exam- ined, diagnosis, description, etc., as well as useful observations on variations and comparisons with related taxa. I found particularly interesting the description and explanation of the development of 509 the second male pleopods in Strigopagurus as this is an aspect of evolutionary significance that has seldom been explored in detail in hermit crabs. The paper is enriched by high quality black and white photographs of cephalic shields and appendages, and SEM micrographs of stridulatory struc- tures. A summary of the geographic and bathymetric distribution of the species is also presented. Worthy of mention is a short but significant paper by the author (Forest, 1995), also in this MUSORSTOM volume, on a Miocene fossil that he has assigned to Ciliopagurus. The title of this study might suggest that it is a revision concerned exclusively with the Tri- zopagurus group of species. Actually it is more than that, as Forest includes an exposition of his vision on the evolution of the Diogenidae, one of the largest, most widespread, and diverse families of hermit crabs. He addresses phylogenetic relationships in general terms, and gives an account of the current status of the family. A useful table comparing the 18 genera known worldwide, and a key for the identification of all genera, are also included. Minimal errors (surely all inadvertent), were detected. Perhaps the most important to note is the illustration that is missing on fig. 21 (p. 85), although a cut-out to be pasted in the blank was mailed with the reprints. In any case, the missing illustration is taken from the literature, i.e., McLaughlin & Bailey-Brock (1975, fig. 2B). There are errors in the Bibliography: the dates and order of Forest's publications (p. 134) are wrong or not in the proper order; the reference cited in the text (p. 54) as "Muroto (1977)", is not listed. This study by Forest may not have any cladograms or other phylogenetic trees, but it is clear that works such as this one are needed before any meaningful phylogenetic analysis or prediction can be made. It proves that the complexity and diversity of hermit crab morphology can be un- raveled, if only one looks closely and carefully. Carcinologists with a penchant to apply modern computer methods to construct phylogenies should take note, as surely they will find many ideas and hypothesis to be tested in this and other of Forest's recent comprehensive works.

LITERATURECITED

FOREST,J., 1952a. Notes préliminaires sur les Paguridae (Crustacés Décapodes) des côtes occi- dentales d'Afrique. I. Définition de Pseudopagurus gen. nov. et de Trizopagurus gen. nov. Bulletin du Muséum national d'Histoire naturelle, Paris, (2) 24 (3): 254-256. - -, 1952b. Sur Trizopagurus caparti gen. et sp. nov., Paguride de la côte occidentale d'Afrique. Bulletin Institut Royal des Sciences naturelles de Belgique, 28 (39): 1-8. - -, 1952c. Contributions la revision des Crustacés Paguridae. I. Le genre Trizopagurus. Mémoires du Muséum national d'Histoire naturelle, Paris, (A, Zoologie) 5 (1): 1-40. - -, 1984. Révision du genre Aniculus (Decapoda, Diogenidae). Crustaceana, (suppl.) 8: 1-91. - -, 1988. Sur le genre Bathynarius gen. nov. (Decapoda, Diogenidae). Bulletin du Muséum national d'Histoire naturelle, Paris, (4) (A) 10 (4): 759-784. - -, 1995. Crustacea Decapoda Anomura: Présence du genre Ciliopagurus Forest, 1995 (Diogenidae) au Badénien (Miocène moyen): C. substriatiformis (Lörenthey, 1929). In: A. CROSNIER(ed.), Résultats des Campagnes MUSORSTOM, 13. Mémoires du Muséum national d'Histoire naturelle, Paris, 163: 151-154. MCLAUGHLIN,P. A. & J. BAILEY-BROCK,1975. A new Hawaiian hermit crab of the genus Tri- zopagurus (Crustacea, Decapoda, Diogenidae), with notes on its behavior. Pacific Science, 29 (3): 259-266.

RAFAELLEMAITRE Department of Invertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, D.C. 20560, U.S.A.