Faxonella clypeata (Hay, 1899)

Morehouse, Reid L. & Tobler, Michael, 2013, Crayfishes (Decapoda: Cambaridae) of Oklahoma: identification, distributions, and natural history, Zootaxa 3717 (2), pp. 101-157 : 126

Faxonella clypeata (Hay, 1899) : Ditch Fencing Crayfish

General charateristics. A small bodied crayfish with a bullet shaped carapace tapering towards the head that rarely exceeds 50 mm in total length. The rostrum is broad and without lateral spines or tubercles and the areola is open. Chelae are narrow and cylindrical with short abruptly tapering fingers that are shorter than the palm’s length. In form I males, gonopods end in two terminal processes and the central projection is long and conspicuous, but does not reach the base of the first pereiopods. The mesial process is short and thick. In ventral view, the gonopods cross each other. In females, the annulus ventralis is freely movable, not fused to sternum, and has two prominent knobs on its anterior margin (Hay, 1899).

Life coloration. The background color is reddish-tan to olive-tan with, two black lines or dashes extending longitudinally along the dorsal surface of carapace and abdomen ( Figure 43 ). The ventral side is tan to white.

Similar species. In Oklahoma, F. clypeata closely resembles F. blairi (see F. blairi section for differences).

Distribution and habitat. Faxonella clypeata is a tertiary burrower and occurs along the lower Mississippi Valley west of the Mississippi River proper from southeastern Missouri, the Gulf Coastal Plains of southeastern Oklahoma, eastern Texas, and Louisiana, eastward to Florida, and northward into Georgia and South Carolina. In Oklahoma, F. clypeata has been collected from three locations, one each in Choctaw, LeFlore, and McCurtain Counties. Hence, it appears that F. clypeata has a broader distribution in Oklahoma than F. blairi . Faxonella clypeata was found to inhabit swamps and standing pools of water in roadside ditches. Our ecological niche model indicates that other potential areas with suitable environmental conditions exist in southeastern Oklahoma and west along major river systems ( Figure 44 ).

Life history. The main study that has examined the life history of F. clypeata was conducted in southern Louisiana (Smith, 1953). In that study, form I males were found in September. Ovigerous females were collected in late September and October, while females with young were collected in December. Pflieger (1996) collected juveniles in March and April in Missouri. Hence, it is likely that populations in southeastern Oklahoma reproduce in the fall as found in Missouri and Louisiana. Life span of F. clypeata ranges between 18 and 24 months (Pflieger, 1996).

Syntopic species. In Oklahoma, no syntopic crayfish species are currently known.

Conservation status. AFS: Currently Stable; Heritage Rank: Widespread (G5); IUCN: Least Concern; ODWC: Not Listed.

Additional resources. Hobbs (1989); Mobberly & Owens (1966); Mobberly & Pfrimmer (1967).

Figures

FIGURES 37 – 44. 37. Cambarus tartarus 38. Potential distribution of Cambarus tartarus (distribution map was not made for this species due to it subterranean lifestyle; climatic variables outside the cave systems do not accurately represent the climate within the cave) 39. Fallicambarus fodiens 40. Potential distribution of Fallicambarus fodiens 41. Faxonella blairi 42. Potential distribution of Faxonella blairi 43. Faxonella clypeata 44. Potential distribution of Faxonella clypeata.