Hyalella, Rogers & Cruz-Rivera, 2021

Rogers, D. Christopher & Cruz-Rivera, Edwin, 2021, A preliminary survey of the inland aquatic macroinvertebrate biodiversity of St. Thomas, US Virgin Islands, Journal of Natural History 55 (13 - 14), pp. 799-850 : 813-814

Hyalella n. sp.

We found an undescribed Hyalella on St. Thomas from Spring Road ghut. The single female specimen was collected from the spring head, in a net placed over the springhead opening. The eyes are present and normal, and dorsal mucronations are lacking. The uropod III ramus is ~0.25x the length of the peduncle, and the first antenna is much shorter than the second. The most interesting character is the telson, which as a marginal row of separated spines, projecting dorsally, like spikes on a crown. We will describe this new species after we collect more material.

Isopoda

Numerous anchialine and groundwater isopoda are known from the Caribbean (Rogers et al. 2020). Although none are reported from the Virgin Islands, we expect that inland aquatic isopods will be found here at some point.

Decapoda

Many freshwater decapods are known from the Caribbean Islands ( Vélez 1967; Beatty 1968; Fransen et al. 1997; Pérez-Reyes et al. 2013). The dendrobranchiate shrimp Acetes americanus (Ortmann, 1893) , Xiphopenaeus kroyeri (Heller, 1862) , Litopenaeus schmitti (Burkenroad, 1936) , and species of Farfantepenaeus sp. could potentially appear in the lowest reaches of coastal streams and estuaries in the Virgin Islands.

Crayfish (Astacida) are native to Cuba and invasive Australian and North American species have been introduced to Puerto Rico ( Hobb 1989; Williams et al. 2001). A single freshwater hippolytid shrimp, Calliasmata rimolii (Chace, 1975) is known from the Dominican Republic, and freshwater Barbouriid shrimp are known from Cuba, the Bahamas, and Cayman Islands.

Atyid shrimp in the genera Micratya, Jonga, Typhlatya , and Potimirim are known through many of the Caribbean islands, including Puerto Rico ( Schmitt 1935; Pérez- Reyes et al. 2013), but only Potimirim americana has been reported from a single site in St. Croix ( Beatty 1968). Two species of Atya have been reported from St. Croix and St. Thomas ( Schmitt 1935; Beatty 1968; Nemeth et al. 2007) and were collected during our surveys. Micratya cooki Karge et al., 2013 is reported from Puerto Rico and the large Atya scabra (Leach, 1816) is common through the Greater Antilles ( Vélez 1967; Karge et al. 2013; Pérez-Reyes et al., 2013). Both species could potentially be found in the US Virgin Islands, but no prior records exist ( Gardner et al. 2008).

Of the Palaemonid shrimp, Macrobrachium acanthurus (Wiegmann, 1836) and Palaemon pandaliformis (Stimpson, 1871) have been reported from Puerto Rico and St. Croix ( Vélez 1967; Beatty 1968; Chase and Hobbs 1969) and Macrobrachium heterochirus (Wiegmann, 1836) has been reported from Puerto Rico ( Vélez 1967; Chase and Hobbs 1969; Pérez-Reyes et al. 2013). There are records that need verification from St. John in Living Ghut and Fish Bay Ghut ( Muchmore 1993). Prior records of two other Macrobrachium species ( Nemeth et al. 2007) are confirmed herein (see below).

Freshwater and semiterrestrial crabs from throughout the region (e.g. Rathbun 1933; Vélez 1967), but without records from the US Virgin Islands, include Leptuca thayeri (Rathbun, 1900) , and Platychirograpsus spectabilis (de Man, 1896) . Minuca vocator (Herbst, 1804) and Sesarma curacaoense (De Man, 1892) have been reported from Puerto Rico, and so may possibly be found in the US Virgin Islands in the future.

Freshwater (including estuaries) and terrestrial crabs with records from the US Virgin Islands, but not found during our surveys include: Minuca rapax (Smith, 1870) , reported from all three main US Virgin Islands ( Rathbun 1933; Beatty 1968; Muchmore 1993); M. mordax (Smith, 1870) , Ucides cordatus (Linnaeus, 1763) , Armases americanum (Saussure, 1858) , and A. angustipes (Dana, 1852) from St. Thomas; Gecarcinus ruricola (Linnaeus, 1758) , and Aratus pisonii (H. Milne Edwards, 1837) from St. Croix, and; Goniopsis cruentata (Latreille, 1802) from both St. Thomas and St. Croix ( Beatty 1968; Chase and Hobbs 1969). Finally, the primary freshwater crab Epilobocera sinuatifrons (A. Milne-Edwards, 1866) is reported from St. Croix and Puerto Rico ( Rathbun 1933; Beatty 1968; Rodríguez 1982). There is no clear information on the specific habitat parameters for this species, but it may be present on St. Thomas or St. John.