PacificScience(1990), vol. 44, no. 4: 417-448 © 1990 by University of Hawaii Press. All rights reserved Revision of the Genera of Gall Crabs (Crustacea: Cryptochiridae)! Occurring in the Pacific Ocean Roy K. KROPP2 ABSTRACT: The coral gall crabs, Family Cryptochiridae, occurring in the Pacific Ocean are reviewed. Fifteen genera, including four new genera, are recognized: Cryptochirus Heller; Dacryomaia, new genus; Fizesereneia Takeda & Tamura; Fungicola Serene; Hapalocarcinus Stimpson; Hiroia Takeda & Tamura; Lithoscaptus Milne Edwards; Neotroglocarcinus Takeda & Tamura; Opecarcinus Kropp & Manning; Pelycomaia, new genus; Pseudocryptochirus Hiro; Pseudohapalocarcinus Fize & Serene; Sphenomaia, new genus; Utinomiella Kropp & Takeda; and Xynomaia, new genus. Host, depth, and distribution records are given for each genus. A key to the females of all gall crab genera is included. THE CORAL GALL CRABS, Family Crypto­ ramous or biramous) of the second pleopod chiridae, are obligate associates of living of the female and the host coral taxon on scleractinian corals. Not only do they reside which the crab species occurred. McCain and in galls, tunnels, or pits in the coral skeleton, Coles (1979) found the second pleopod to be but they also feed on the host coral mucus and uniramous on one side of the abdomen of an tissues (Kropp 1986). Though the family has individual, biramous on the other, and vari­ been known for 130 yr, its taxonomy has been able among individuals of Utinomiella dimor­ marred by many errors. These errors have pha (Henderson 1906). I have made similar resulted from failures to consider type mate­ observations for this and other species among rial or available literature, use of inappro­ my collections from Micronesia. Crypto­ priate characters to define taxa, or failure to chirids show some degree of host specificity, follow proper taxonomic procedures. which some authors thought could be used to Two problems related to failure to consider define genera (Fize and Serene 1957, McCain type material were resolved by the reestab­ and Coles 1979). Both features subsequently lishment of Lithoscaptus Milne Edwards and were shown to be unreliable (Kropp and Cryptochirus hongkongensis Shen, the latter as Manning 1987). the type species of Neotroglocarcinus Takeda In a monograph ofthe gall crabs from Viet­ & Tamura (Kropp 1988a,b). nam, Fize and Serene (1957) created a new Two characters inappropriate for use in the genus, Neotroglocarcinus, and initiated the definition of genera were the nature (uni- use of subgenera in the genus Troglocarcinus Verrill. The subgenera they established were based on the family of corals on which the 1 Contribution no. 284 from the University of Guam crabs were found. However, they erred in Marine Laboratory. Financialsupport was provided by creating the subgenus Mussicola by including theUniversity of Maryland Department ofZoology and within it T. corallicola Verrill, the type species Graduate School, a grant to G. J. Vermeij by the Bio­ logical Oceanography Section of the National Science of Troglocarcinus. They further erred by not Foundation, and the Lerner-Gray Fund for Marine naming type species for any of their newly Research. This is from a dissertation submitted to the created genus-group taxa. Thus, the new Graduate School, University of Maryland, in partial ful­ genus-group names were unavailable. fillment of the requirements for thePh.D.degree in zoo­ logy. Manuscript accepted 10 February 1990. Serene (1966) made two generic names 2 Presentaddress: Battelle Ocean Sciences, 1431 Spin­ available when he designated Cryptochirus naker Drive, Ventura, California 93001. rugosus Edmondson as the type species of 417 418 PACIFIC SCIENCE, Volume 44, October 1990 Favicola and Troglocarcinus utinomi Fize & and 1986. Specimens from these collections Serene as the type of Fungicola. His actions have been deposited in the National Museum also helped establish the host taxon as a gene­ of Natural History, Smithsonian Institution ric character. (NMNH), Washington, D.C.; the Bernice P. By the beginning of the 1980s the taxono­ Bishop Museum (BPBM), Honolulu, Hawai'i; mic situation of the family was far from and the Natural History Museum of Los serene, but the work of Takeda and Tamura Angeles (LACM), Los Angeles, California. in Japan had begun to unravel some of the Supplementary material was borrowed from confusion. Takeda and Tamura (l981b) re­ the BPBM; the NMNH; the British Museum moved Pseudocryptochirus as a "catch all" of Natural History (BMNH), London, Eng­ taxon by creating two new genera, Hiroia and land ; the Museum National d'Histoire Natu­ Utinomia, for some species previously as­ relle (MNHN), Paris , France; the Naturhis­ signed to Pseudocryptochirus. Utinomia torisches Museum (NMW), Vienna , Austria; Takeda & Tamura, 1981 was later determined and the National Science Museum (NSMT), to be a junior homonym of Utinomia Tom­ Tokyo, Japan. I examined the types of many linson , 1963, a genus of acrothoracican bar­ species; these are marked by an asterisk in the nacle, and was replaced by Utinomiella Kropp lists of species. & Takeda 1988. Most of the figures are based on material Takeda and Tamura (1980b) also erected a from Micronesia and were prepared with the new genus, Fizesereneia, to accommodate use of a camera lucida on a Wild M-5 dissec­ species placed in the erroneously created Mus­ tion microscope or were traced from scanning sicola Fize & Serene, 1957. However, they did electron microscope (SEM) micrographs. The not realize that Mussicola could be used as type species of each genus is figured. Setae on an available name by designating one of the the surfaces of the carapace and pereopods species in it as its type. Kropp and Manning are not shown. Specimens for SEM study were (1987) rectified this by naming T. corallicola prepared as described in Kropp (1986). as the type species of Mussicola, rendering I have restricted the synonymies to the first Mussicola a junior synonym of Troglocar­ usage ofa particular name for a taxon, includ­ cinus. Takeda and Tamura (1980b) further ing erroneous spellings. Abbreviations used in erred by misidentifying the type species of the text or figures are as follows: m, meters; their new genus Fizesereneia. Kropp (l988c) mm, millimeters; MXL, maxilla; MXP, maxil­ petitioned the International Commission on liped; P, pereopod; PLP , pleopod; and TL, Zoological Nomenclature to confirm Troglo­ type locality. carcinus heimi Fize & Serene, 1956 as the type In the diagnoses the male P-1 is described species of Fizesereneia . as robust if the height of the manus is sub­ However, many morphological inconsis­ equal to the length of its dorsal margin, slen­ tencies within the generic structure of the der if the height ofthe manus is much less than family still remained by the mid-1980s. Here, the length of its dorsal margin. Similarly, the I use morphology to reorganize the generic propodus ofleg P-2 of the female is described placement of the species of gall crabs occur­ as thick if its height is subequal to its length; ring in the Pacific, removing totally the con­ slender if the length is 1.5 or more times the cept of host affinity as a generic character. I height. The median indentation of the an­ also pro vide a key to the females ofall known terior margin of the epistome is characterized cryptochirid genera . The species of gall crabs as narrow if its maximum width is less than occurring in the Atlantic were reviewed by half or wide if its maximum width is greater Kropp and Manning (1987). than half the width of the anterior margin. Also, the median indentation is termed shal­ low if its depth is less than half or deep if its depth is greater than half the length of the MATERIALS AND METHODS epistome. In some genera the median inden­ I collected much ofthe material used in this tation is barely noticeable and is termed revision in Micronesia and Hawai'i in 1984 slight. Revision of Pacific Gall Crab Genera-i-Knorr 419 I have listed only those host, depth, and dicates unpublished data from my collections distribution records that I am reasonably cer­ in Micronesia and Hawai'i. tain are accurate. The acronym "RKK" in- KEY TO GENERA OF GALL CRABS , FAMILY CRYPTOCHI RIDAE (Based on Females) I. Carapace deflected anteriorly .. .. .. .. .. ... .... ... ... .. 2 I. Carapace not deflected anteriorly. ... ... .. ... ... .. .. ... ..... .. 10 2. Anterior extension of sternite of P-I smooth. .. .... ... .. ... .. ... ... 3 2. Anterior extension of sternite of P-I with granules or tubercles . .... ... .. ... 6 3. Anterior carapace with two bowl-shaped concavities 4 3. Anterior carapace without bowl-shaped concavities.. ........ ... .. .. ..... 5 4. Distal margin of antennal segment 2 with lateral spine; pterygostomial region not fused to carapace. .... .. .. .... .. .. ... ... .. .. .. Pelycomaia Kropp, new genus 4.Distal margin of antennal segment 2 without lateral spine; pterygostomial region fused to carapace Pelycomaia 5. Pterygostomial region fused to carapace; P-2 merus lacking distomesial expansion . ... · Lithoscaptus 5. Pterygostomial region not fused to carapace; P-2 merus with distomesial expansion . .. · Troglocarcinus (Atlantic) 6. P-2 merus with distomesial expansion 7 6. P-2 merus without distomesial expansion ... .. .. ..... ... .. .... ... .. .. 8 7. Pterygostomial region fused to carapace; P-4 sternite with median suture . ·. .. .. .. ... ... .. .. ... .. ... .. ... .. Opecarcinus 7. Pterygostomial region not fused to carapace; P-4 sternite