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The phylogenetic structure of 23 populations of Crangonyx hobbsi, a stygobitic amphipod species endemic to the Floridan aquifer, is detailed. Molecular genetic analyses (based on three genes the nuclear 18S rDNA, 28S rDNA, and mitochondrial 16S rDNA) point to the presence of at least two phylogenetic clades within the aquifer. These clades align into two major zoogeographic regions, the Northern Suwannee River Basin and the Coastal and Central Lowlands in the Florida peninsula. Three species delimitation models indicate that the Northern Suwannee River Basin Clade represents a species level differentiation from C. hobbsi sensu stricto. Morphological analyses support the molecular analyses, revealing the presence of several taxonomically significant differences between the two species, including presence/absence of calceoli on the second antennae of males and differences in telson shape in both sexes. Additionally, the molecular diversity of C. hobbsi sensu stricto was shown to be surprisingly variable, suggesting the potential presence of additional diversity within the taxon.

Stygobromus doughertyensis n. sp. is described from groundwater habitats in Jackson County, Florida and Dougherty County, Georgia, USA using both morphological and molecular methods. This species occurs syntopically with the morphologically similar S. floridanus, which is newly recorded in Jackson County. The occurrence of S. floridanus in Jackson County marks a range extension for this species, which was described from two caves in Washington County, Florida. The description of S. doughertyensis n. sp. brings the number of described species in the genus Stygobromus to 142 and marks the second species of Stygobromus to be described from the Floridan aquifer.

Crangonyx manubrium, a new stygobitic species, is described from hypogean localities in Jackson County, Florida. This analysis is based on detailed morphometric and genetic comparisons of J...

The superfamily Bogidielloidea is one of the most wide-ranging hypogean amphipod taxa currently known, comprising over 130 species in 43 genera occurring on every continent except Antarctica. This large distribution among such cryptic organisms is curious, especially when combined with weak morphological characters uniting the superfamily. A unique new genus and species of bogidielloid amphipod, Simplexia longicrus, gen. et sp. nov., described from Terrell County, Texas, sheds light on the evolutionary relationships within this grouping. Molecular phylogenetic analyses of the order Amphipoda using two nuclear genes and one mitochondrial gene reveal that this species and the sympatric Parabogidiella americana form a clade removed from other sequenced members of Bogidiellidae sensu stricto, and, as such, the two species are placed in the newly erected Parabogidiellidae, fam. nov. Additional phylogenetic analyses of the cosmopolitan Bogidiellidae are recommended to further resolve its systematics.

Crangonyx ephemerus n. sp. and Crangonyx pseudoephemerus n. sp. are described from the headwaters of the St. Marks River in Leon County, Florida, based on detailed morphological and molecular comparisons with the closely related species Crangonyx floridanus Bousfield, 1963. The morphological and molecular data, including three species delimitation models, lend support to the hypothesis that the taxon C. floridanus sensu lato represents a species complex. Diagnostic morphological characteristics are highlighted and discussed within this group to assist in future morphological analyses.

A new stygobitic amphipod, Idunella verrilli, is described from the subterranean marine waters of Green Bay Cave, Bermuda. Specimens were collected during SCUBA exploration of the cave system in 1997. This species is readily distinguished from the only other liljeborgiid amphipod found in Bermuda, Idunella sketi Karaman, 1980.

— Crangonyx hobbsi Shoemaker, 1941, a variable stygobitic amphipod endemic to the Floridan aquifer, is redescribed from topotype material and populations adjacent to the type locality. In ...

Mexistenasellus floridensis sp. n. is described from Hole in Wall Cave, Jackson County, Florida. The discovery of this unique isopod nearly doubles the range of the Family Stenasellidae in North America, which was previously known from Oaxaca, Mexico to southern Texas, USA. This is the first stenasellid reported swimming in the water column of a cave, a curious finding for an isopod that belongs to a group that is generally more adapted to inhabiting interstitial spaces. Mexistenasellus floridensis occurs syntopically with the subterranean asellid Caecidotea putea. Both species have been observed swimming in the water column, although neither has apparent anatomical adaptations for swimming as compared to the natatory pereopods of Remasellus parvus, an asellid that occurs in caves in Alachua, Madison and Wakulla counties, Florida.

Two new genera, Paraholsingerius and Tamaweckelia, and two new species, P. mexicanus and T. apalpa are described from caves in eastern Coahuila and southern Tamaulipas, Mexico, respectively. Holsingerius smaragdinus, previously known from a single cave in Val Verde County, Texas, is placed in the new genus Paraholsingerius, and a second population of P. smaragdinus is recorded from northern Coahuila, Mexico. A new record for Paramexiweckelia in north-central Coahuila is documented.

Three new species of Tegano are described, two from caves on Panglao Island, Bohol, Philippines, and one from a cave on Peleliu Island, Palau. Sriha vagabunda from Sri Lanka is reassigned to the genus Tegano based primarily on the high degree of similarity between Sriha vagabunda and species of Tegano and the fact that these species exhibit a great deal of variation in the reduction of the mandibular palp. A new species of Melita with characters intermediate between those defining the genera Abludomelita, Melita, and Paraniphargus is described from a spring on Guam. The characters of the new species and studies by previous authors suggest that Abludomelita may not be as distinct from Melita as previously believed. The troglomorphic genus Paraniphargus from the Andaman Islands and Java is re-evaluated and synonymized with Melita.

Bahadzia caymanensis, a new stygobitic species is described from a shallow, weakly brackish-water pool in a small cave on Grand Cayman Island in the Cayman Islands. Further exploration and collecting from the type-locality of Bahadzia yagerae in Cuba has provided more data, allowing for a thorough redescription of this species. With the description of Bahadzia caymanensis, there are now 11 species within the genus. Revised phylogenetic and biogeographic analyses of Bahadzia offer further support for a close phylogenetic relationship between Bahadzia and the predominately freshwater genera Mayaweckelia and Tuluweckelia on the Yucatan Peninsula.

A relatively large, distinct new species of the subterranean amphipod crustacean genus St ygobromus (Amphipoda: Crangonyctidae) measuring 13 mm in length is described from Skipper Spring, a cave spring in the northwestern “panhandle” of Florida, USA. This is the first species of the genus described from the state of Florida where it is described from only 3 females. A fourth much smaller specimen of this species was collected from nearby Miller’s Crossing Spring on Holmes Creek. All other stygomorphic amphipod species recorded from the state of Florida have been in the genus Crangonyx.

Bactrurus speleopolis, a large stygobitic amphipod crustacean in the family Crangonyctidae is described from specimens collected from a lake in Cave City Cave, Sharp County, Arkansas, and is the second species of Bactrurus Hay, 1902 recorded to date from the state. This species may also occur in Marble Falls Cave in Marion County, but sexually mature specimens are needed to verify that occurrence. The description of B. speleopolis raises the total number of species in Bactrurus to eight. The genus is widespread in subterranean groundwaters of the east-central United States and is also recorded from a few localities farther east in the southern Appalachians.