The aquatic annelid fauna of the San Marcos River headsprings, Hays County, Texas

Abstract

The San Marcos River in Central Texas has been well studied and has been demonstrated to be remarkably specious. Prior to the present study, research on free-living invertebrates in the San Marcos River only dealt with hard bodied taxa with the exception of the report of one gastrotrich, and one subterranean platyhelminth that only incidentally occurs in the head spring outflows. The remainder of the soft-bodied metazoan fauna that inhabit the San Marcos River had never been studied. Our study surveyed the annelid fauna and some other soft-bodied invertebrates of the San Marcos River headsprings. At least four species of Hirudinida, two species of Aphanoneura, one species of Branchiobdellida, and 11 (possibly 13) species of oligochaetous clitellates were collected. Other vermiform taxa collected included at least three species of Turbellaria and one species of Nemertea. We provide the results of the first survey of the aquatic annelid fauna of the San Marcos Springs, along with a dichotomous key to these annelids that includes photos of some representative specimens, and line drawings to elucidate potentially confusing diagnostic structures.

The life cycle of Huffmanela huffmani Moravec, 1987(Nematoda: Trichosomoididae), an endemic marine-relict parasite of Centrarchidae from a Central Texas spring

“…This conclusion complicated our life-cycle investigations, as there are at least 13 species of amphipods known to occur locally (Holsinger andLongley 1980, Gibson et al 2008) and since the literature on the annelids of the SMR was almost non-existent. Therefore, it became necessary to survey the annelids of SMS, which was found to contain at least 20 benthic species, including at least 16 species of oligochaetes, 2 aphanoneurans and 3 leeches (Worsham et al 2016). Benthic invertebrates were collected from near spring openings using a Ponar grab sampler.…”

Drainage basin checklists and dichotomous keys for inland fishes of Texas

“…Dichotomous keys usually are created for taxa within geopolitical boundaries (e.g., Hubbs et al 2008); however, geopolitical boundaries often are arbitrary to species distributions (Forman 2014). Recent development and use of dichotomous keys along natural boundaries, such as drainage basin (Worsham et al 2016), provide finer resolution on species distributions and reduce probability of identification errors by removing species not occurring within a natural boundary.…”