Three new microcerberids (Isopoda: Microcerberidae) from subterranean freshwater habitats in Texas, USA

ABSTRACT

The stygobiontic genus Texicerberus gen. nov. and the three species T. amistad sp. nov., T. schotteae sp. nov., and T. castilloi sp. nov. are described from freshwater aquifer or hyporheic sites across central and western Texas, USA. The status of the new genus and species is based on morphological characters that distinguish them from all other described Microcerberidae from both marine and freshwater environments. Cephalon without rostral projection, coxae II–IV rounded, medial margin of antenna article 3 angulate but not produced as spine, male pleopod II endopod uniramous, and male pleopod IV biramous are among the characters that distinguish Texicerberus gen. nov. from other genera in the family. Collected from deep karst aquifer wells, karst springs, and the hyporheic zone along the Rio Grande (Rio Bravo del Norte), these three new species represent the first documented occurrences of Microcerberidae in Texas and substantially increase the described diversity in the family in North America and from freshwater environments globally. Additional sampling, especially in the hyporheic zone, is expected to reveal additional diversity in Texas. Future collection and analysis of molecular data will be required to understand the evolutionary relationships among these and other species.

KEYWORDS:

• Edwards Aquifer
• stygobiont
• groundwater biodiversity
• hyporheic zone
• karst
• Texicerberus gen. nov

Acknowledgements

Support was provided, in part, by the US Fish and Wildlife Service (USFWS), Grant title TX T-79-R-3, F16AF00688, under the authority of the State Wildlife Grant Program (CFDA#15.634) issued to Texas Parks and Wildlife Department, and through a grant from the Cave Conservancy Foundation. The City of Austin, Big Bend National Park, and Bill Fawcett provided access to sites. Thanks are due to Aaron P. Swink for helping with sampling and sorting samples from the San Marcos Artesian Well. The Texas State University Analysis Research Service Center facilitated the use of a confocal laser scanning microscope for morphological examination.

Disclosure statement

No potential conflict of interest was reported by the authors.

Geolocation information

Rio Grande hyporheic zone at upstream mouth of Boquillas Canyon: 29.19941°N, 102.91727°W; Rio Grande hyporheic zone at mouth of Tornillo Creek: 29.17760°N, 102.99745°W; Snake Spring: 29.89588°N, 100.98188°W; San Marcos Artesian Well: 29.88958°N, 97.93647°W; Eliza Springs: 30.26428°N, 97.77014°W; Target Well: 30.23242°N, 97.79314°W.

Additional information

Funding

This work was supported by the Cave Conservancy Foundation [no grant number provided]; US Fish and Wildlife Service [TX T-79-R-3, F16AF00688].