SYSTEMATICS Redescription of the Male of Coenaletes caribaeus (Collembola: Coenaletidae) Associated with Hermit Crabs (Decapoda: Coenobitidae) JOSE ´ G. PALACIOS-VARGAS, LEOPOLDO Q. CUTZ, AND CARMEN MALDONADO Laboratorio de Ecologõ ´a y Sistema ´ tica de Microartro ´ podos, Departamento de Biologõ ´a, Facultad de Ciencias, UNAM 04510 Mexico, DF Ann. Entomol. Soc. Am. 93(2): 194Ð197 (2000) ABSTRACT The male of Coenaletes caribaeus is described and illustrated. It is recorded for the Þrst time from Mexico, with specimens from hermit crabs Coenobita clypeatus, from beaches in Quintana Roo. Drawings and scanning electron microscope pictures are included. KEY WORDS Coenaletes, Collembola, hermit crabs COLLEMBOLA ARE WELL known as soil and litter inhab- itants, where they can be very abundant and diverse. Very few species live on the sea shores, because the families Actaletidae and Isotogastruridae, and some members of the families Isotomidae (e.g., Archiso- toma), Neanuridae, Entomobryidae, and Hypogastru- ridae are localized in marine littoral environments (Christiansen and Bellinger 1988, Palacios-Vargas and Va ´ zquez 1988). It was only in 1980 that 1 species was found to be commensal with hermit crabs (Jacque- mart 1980), for which Bellinger (1985) created the new family Coenaletidae. Only 2 members of this monogeneric family of Col- lembola are known, Coenaletes vangoethemi Jacque- mart, 1980 from New Guinea, and C. caribaeus Bell- inger, 1985 from Guadeloupe. They have been found only associated with hermit crabs of the genus Coeno- bita (Crustacea: Decapoda). C. caribaeus was also found in Dominican Republic by Mari Mutt (1994). Coenaletes Bellinger, 1985 Collembola Arthropleona, Entomobryoidea; no pig- ment, no eyes, and no postantennal organ; mandible with molar plate but without apical teeth; maxilla with 6 subequal lamellae; pronotum reduced, 3rd and 4th abdominal segments fused and elongated, other trunk segments distinct; plurichaetotic, ordinary setae con- ical and acuminate, varying in length; differentiated Þne setae only on 2nd, 3rd, and 4th abdominal tergites, trochanters and apices of tibiotarsi; differentiated blunt setae only on antennal segments, abdominal tergites and (in males) lateral margins of trunk tergi- tes; dorsal apex of tibiotarsus excavate at base of un- guis; pretarsal setae on papillae; unguis with greatly enlarged lateral teeth and capable of folding dorsally into recess as at end of tibiotarsus, furcula well de- veloped, reaching beyond ventral tube with dens smooth, bearing few setae; mucro falcate, fused to dens. Coenaletes caribaeus Bellinger, 1985 Redescription. Fourth antennal segment in male with 2 subapical organs in separate minute pegs and 8th thin, uniform blunt setae in apical half. Third antennal segment with 8 blunt setae of various sizes on outer apical face and 2 similar spines with rounded apex and 1 spiniform setae at the base of the segment, and 4 bothriotricha ventrally (Figs. 1 and 8). Second antennal segment with 1 blunt setae on outer apical face, 2 different spines with rounded apex, and 6 bothriotricha (Figs. 1 and 8). First antennal segment with 9 setae in distal ring and 5Ð 6 more basal setae, 2 setulae and 1 thick spine on outer apical face. Head somewhat wider than long (Figs. 1 and 7), with oral region barely projecting beyond anterior curve of front; interantennal distance subequal to head length. Mandible with well-developed molar plate; without apical teeth (Figs. 3 and 4). Maxillary capitulum compact, with 6 curved lamellae, the inner 4 Þnely fringed internally; maxillary outer lobe not recognized (Fig. 5). Labrum with 7 setae. Labium with 3 distal papillae, each bearing 1 apical and 2 subapical setae (Fig. 6). Thorax with short blunt sensory setae: 1 1 1 laterally on 2nd and 3rd segments, and 2 1 2 in Þles behind inner bothriotricha of fused 3rd and 4th abdominal segments. Thorax III with a group of 4 differentiated spines at each side (Figs. 1 and 9). Abdominal seg- ments from I to III with 1 spine on each side, the last one upward and sharp (Figs. 2 and 9). Macrochaetae: 1 1 1 dorsally and 3 1 3 laterally on fused 3rd and 4 abdominal segments; 1 1 1 laterally on 5th abdominal segment; 5 1 5 very large setae on 6th abdominal segment (Fig. 2). 0013-8746/00/0194Ð0197$02.00/0 q 2000 Entomological Society of America