Saturday, September 17, 2016

[Crustacea • 2016] Cambarus (Jugicambarus) adustus • A New Species of Crayfish from northeastern Kentucky delimited from the Cambarus (J.) aff. dubius species complex


Dusky Mudbug | Cambarus (Jugicambarusadustus 
 Thoma, Fetzner, Stocker & Loughman, 2016  

FIGURE 4. Cambarus (Jugicambarus) adustus, new species, from the type locality showing natural coloration.
 locality: roadside ditch serving as a tributary to Big Branch of Salt Lick Creek, NE of Glen Springs, Lewis County, Kentucky.

Abstract

A new species of burrowing crayfish, Cambarus (Jugicambarusadustus, is described from Lewis County in northeastern Kentucky, USA. The new species is most similar morphologically to C. dubiusCambarus adustus coloration differs from C. dubius by lacking red, orange and blue hues, and instead is brown over the entire body surface. Morphological differences between C. dubius and C. adustus exist in the form I male gonopod, with C. adustus possessing a caudal knob, while C. dubius does not. In addition, the lateral carapace of Cadustus is distinctly tuberculate, whereas in C. dubius the carapace lacks extensive tuberculation. Cambarus (J.) adustus appears to have an extremely small geographic range (~19.5 km2), and as such we suggest its consideration for both state and federal levels of protection.

Keywords: Crustacea, Appalachian Mountains, Cambaridae, Cambarus, crayfish, Decapoda, new species




Life history. Collections have been made in May, June, August, September, and October. First form males, second form males, and females have been observed in all months sampled. No ovigerous females or young-of year have been observed.

Crayfish associates. Cambarus thomai and Cambarus ortmanni are found burrowing in adjacent areas. In streams of the area there is a member of the Orconectes subgenus Procericambarus present. It is not clear if these populations represent an undescribed species or are just a geographic variant of Orconectes raymondi Thoma and Stocker 2009.

Relationships. Cambarus adustus is assigned to the subgenus Jugicambarus based on the presence of a cristiform row of tubercles on the mesial margin of the chelae. It appears to be most closely related to C. dubius, C. pauleyi, and other members of the C. aff. dubius complex. It is hypothesized that the species had become established in the preglacial Portsmouth River prior to the onset of the Quaternary. Cambarus adustus displays a caudal knob similar to, but smaller than, Cambarus bouchardi Hobbs 1970. This character state is not thought to reflect a close relationship between the two species.

Etymology. The species epithet (adustus = L. brown) is chosen to recognize the overall coloration of this species. The suggested vernacular name is Dusky Mudbug.

Conservation status. Cambarus (J.) adustus, new species, is narrowly distributed, with a current extent of occurrence of 19.5 km2  in Lewis County, Kentucky. It is best classified as Endangered following Taylor et al. (2007), Endangered (B2ab(iii), ver. 3-1) using IUCN criteria (IUCN 2001), G1 using NatureServe. It should be listed as S1 by the state of Kentucky, and Endangered by the USFWS.

Range and specimens examined. This species has only been found in Lewis County, Kentucky in the Quicks Run, Salt Lick Creek and the eastern edge of Cabin Creek basins. Adjacent areas in Kentucky and Ohio have been searched but no other populations have been found. Taylor and Schuster (2004) did not report C. dubius from Lewis County, KY. Their closest record was a single site reported from Rowan County, KY in the Licking River basin.


Roger F. Thoma, James W. Jr. Fetzner, G. Whitney Stocker and Zachary J. Loughman. 2016. Cambarus (Jugicambarusadustus, A New Species of Crayfish from northeastern Kentucky delimited from the Cambarus (J.) aff. dubius species complex.
 Zootaxa. 4162(1); 173–187. DOI: 10.11646/zootaxa.4162.1.9

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