Tulumella grandis Yager, 1987
Taxonomic Characterization: The largest known thermosbaenacean to date. Eyes absent, small rounded eyestalks present. Carapace covering pereonites 1-7. Pigmentation lacking. Antenna 1 very long, about 3/4 of body length. Antenna 2 with exopod as single scale. Left mandible with 4-cusped incisor process and 3 or 4 cusped lacinia mobilis, right mandible lacking lacinia mobilis. Maxilla 1 endopod with 4 long denticulate spines. Maxilla 2 basal elements with spoon-shaped distal setae bearing cuticular fringe. Dactyl of pereopods 2-7 with serrate apex. Telson with 5-6 pairs of spines (Yager, 1987).
Ecological Classification: Stygobitic
Size: Length from 4.5 to 5.2 mm
Number of Species in Genus: Three, all stygobitic
|Tulumella: genus range|
Species Range: Known from five caves (Lucayan Caverns, Sagittarius Cave, Bahama Cement Cave, Asgard Cave, Lucy's Cave) in Grand Bahama and one cave each in Abaco (Dan's Cave) and South Andros (El Dorado Cave).
Closest Related Species: T. grandis shows a closer relationship to T. unidens than it does to T. bahamensis.
Habitat: Anchialine, inland blue hole, limestone caves
Ecology: Tulumella grandis is a relatively euhaline neritic species that lives near the density interface of the halocline. In Lucayan Caverns, thermosbaenaceans are the most abundant animal in the water column, with as many as 20 individuals per cubic meter. They are typically found in association with a number of other stygobitic taxa including remipedes (Speleonectes, Cryptocorynetes, Godzillius, Pleomothra and Godzilliognomus), amphipods (Bahadzia and Spelaeonicippe), isopods (Bahalana), mysids (Stygiomysis), ostracods (Deeveya and Spelaeocia) and fish (Lucifuga).
Life History: The 23 specimens reported by Yager (1987) were all females. One was overgerous.
Evolutionary Origins: The distribution of thermosbaenaceans with hypogean species in the West Indies, Yucatan, Texas, the Canary Islands, the Mediterranean region, Somalia and Cambodia is taken to indicate a Tethyan origin associated with the breakup of Pangea in post-Jurassic time (Schram, 1986; Cals & Monod, 1988).
Conservation Status: Known from inland blue hole caves on both the Great Bahama and Little Bahama Banks.
Contributor: Jill Yager, Antioch College, Yellow Springs, OH
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