Anne C. Cohen

IT'S ALL ABOUT SEX: BIOLUMINESCENT COURTSHIP DISPLAYS, MORPHOLOGICAL VARIATION AND SEXUAL SELECTION IN TWO NEW GENERA OF CARIBBEAN OSTRACODES

Abstract A large clade of cypridinid ostracodes, found only in the Caribbean, uses species specific courtship displays of secreted luminescence, produced by males, to attract photically silent females to mate. We recently described two new genera, Photeros and Enewton, which are part of this clade (Cohen and Morin, 2010). Within the various subclades of these signaling ostracodes in the Caribbean, only Photeros has been shown to have species-specific differences in both their luminescent displays and the morphology of the large male copulatory (eighth) limb (Cohen and Morin, 2010). The apparent ancestral display pattern, which occurs among at least some species in all the signaling clades of Caribbean ostracodes, is produced as a series of pulses of light secreted into the water column mostly in a vertical pattern, either upward or downward, above species-specific habitats. The pulses are of fairly long duration and become shorter and closer together. A derived pattern of very rapid pulses, which also shows within train interpulse distance shortening, is found only in the genus Photeros. It is likely that the high diversity found in this clade and other signaling clades has been driven by their life history patterns in conjunction with sexual selection acting via the courtship displays and their reproductive structures.

VARGULA MORINI, A NEW SPECIES OF BIOLUMINESCENT OSTRACODE (MYODOCOPIDA: CYPRIDINIDAE) FROM BELIZE AND AN ASSOCIATED COPEPOD (COPEPODA: SIPHONOSTOMATOIDA: NICOTHOIDAE)

Abstract A new species of bioluminescent ostracode, Vargula morini from Carrie Bow Cay, Belize, is described on the basis of morphology and mating displays. Every night, males of V. morini produce an elaborate species-specific bioluminescent courtship display in order to attract females. These displays occur over coral or coral rubble, beginning near the sea surface and continuing as a series of rapid flashes produced in a downward direction. A nicothoid copepod was found living within the posterodorsal area of the valves of some V. morini. Scanning electron micrographs of these minute ostracode parasites are presented here for the first time.

Two New Bioluminescent Ostracode Genera, Enewton And Photeros (Myodocopida: Cypridinidae), with Three New Species from Jamaica

Abstract Two new genera (Photeros and Enewton) and three new species of bioluminescent signaling ostracodes (Myodocopida: Cypridinidae) from Jamaica are described. They belong to a large cypridinid clade with male mating displays that we have found only in the Caribbean Sea. The species-specific displays and habitats in which each occurs are an integral part of each species definition. We postulate that the signaling clade has undergone rapid evolution driven by sexual selection particularly in Photeros Cohen and Morin, the only ostracode with both species-specific mating displays and clear species-specific morphological characters in the large male copulatory (eighth) limbs for each species (see also Morin and Cohen, 2010). Photeros comprises at least 19 species that are superficially somewhat similar in morphology (including 3 new species, all with authorship attributed to Morin and Cohen, 5 reassigned herein and 11 undescribed). The new Jamaican species are P. jamescasei, P. johnbucki, and P. mcelroyi. Species reassigned herein to Photeros are Vargula parasitica (with additional description based upon types and new Jamaican material), V. morini and V. annecohenae (from Belize), and V. graminicola and V. shulmanae (from Panama, with new information on lips and copulatory limbs). Photeros parasitica is a carrion feeder, not a parasite. We reassign Vargula harveyi to a new genus Enewton Cohen and Morin, with a more complete species description, including that of the previously unknown males and their bioluminescent mating displays. Morphological and display characters of genera and species are compared in tables. Homologies of morphological characters (some new), particularly in the upper lip, first antenna, seventh limb, and male eighth (copulatory) limb are described and discussed. Because signaling species are highly endemic, shallow signaling species are threatened by an increase in artificial lighting at night where their mating displays now occur. Videos of the displays from the three new species of Photeros are provided in the electronic accessory materials (Appendix 5).