Cambarus (Puncticambarus) robustus Girard, 1852

Loughman, Zachary J. & Simon, Thomas P., 2011, Zoogeography, taxonomy, and conservation of West Virginia's Ohio River floodplain crayfishes (Decapoda, Cambaridae), ZooKeys 74, pp. 1-78 : 15-18

Cambarus (Puncticambarus) robustus Girard, 1852

Cambarus robustus Girard 1852:90. Hagen 1870:80, fig. 167. Crocker and Barr 1968:118, figs. 30, 39, 48, 55, 65, 67, 81. Page 1985:439-440, figs 171-173. Taylor et al. 1996:29. Taylor et al. 2007:383.

Cambarus Bartonii robustus Faxon 1885:9.

Cambarus bartonii robustus Faxon 1890:622.

Cambarus (Bartonius) bartoni robustus Ortmann 1905b:122.

Cambarus (Cambarus) bartonii robustus Fowler 1912:341.

Cambarus (Cambarus) bartonii robustus Ortmann 1931:126.

Cambarus (Bartonius) robustus Creaser 1931:260.

Cambarus (Puncticambarus) robustus Hobbs 1969: 101, figs. 1c, 13a, 17o; 1974:21, fig. 77; 1989:27, fig. 104. Jezerinac et al. 1995:155-171, fig. 75 a– 75H. Taylor and Schuster 2004:103-106, figs. 74A, 74B, 75 A– 75H.

Diagnosis.

Rostrum narrow to slightly broad, margins reduced and parallel, terminating in gentle angle cephalically to form acumen terminating in a single upturned spiniform tubercle; postorbital ridges prominent, cephalic margin with tubercle; cephalothorax dorsoventrally flattened in profile, anterior portion weakly vaulted; 2-5 punctations across narrowest region of areola; branchiostegal region moderately punctate, with small tubercles; chelae robust; mesial surface of palm consisting of two rows of defined tubercles; first row with 7-9 rounded tubercles; second with 5-7 smaller tubercles; additional tubercles scattered over dorsal region of palm; three prominent subpalmar tubercles present; first form gonopods contiguous at base, with 2 terminal elements bent 90° to base; central projection with distinct subapical notch; total length of central projection equal to mesial process length; mesial process bulbous, truncating distally; second form gonopod non-corneous and and blunt; annulus ventralis rhomboid in shape, embedded shallowly in sternum and movable.

Color in life.

Carapace dorsally brown; cephalic region reddish brown, branchial region pinkish brown to light brown; cervical groove black; rostrum margins orange or red; chelae olivaceous green to green; tubercles on chelae yellow or orange; dactyl and fixed finger denticles cream or yellow; perieopods green or light blue; abdomen terga bodies dorsally brown or olivaceous brown; bordered in red, ventral surfaces cream or white.

Specimens examined.

Cambarus robustus were collected from five counties at seven localities, as listed below.

HANCOCK COUNTY: Kings Creek at RT 2 crossing, 40.435715 -80.592514; 17 October 2005 - (WLU 05101701), 4 I♂, 2 II♂, 1 ♀. MARSHALL COUNTY: Long Run at Long Run/Fish Creek confluence, 39.805878 -80.8052; 30 October 2005 - (WLU 05103002), 2 ♀. Fish Creek at RT 2 crossing, 39.808643 -80.81616; 30 October 2005 - (WLU 05103002), 1 I♂, 2 ♀. PLEASANTS COUNTY: Ben’s Run at RT 2 crossing, 39.46337 -81.08457; 28 July 2005 - (WLU 05072802), 3 ♀. TYLER COUNTY: Cow House Run at RT 2 crossing, 39.551327 -81.01001; 28 July 2005 - (WLU 05072804), 1 II♂. WETZEL COUNTY: Fishing Creek at RT 2 crossing, 39.63576 N/ -80.85848 W; 20 July 2005 - (WLU 05072001), 1 I♂, 1 ♀. Proctor Creek at RT 2 crossing, 39.70037 N/ -80.81791 W; 9 July 2008 - (WLU 08070901), 2 II♂, 1 ♀.

Distribution.

Cambarus robustus has an extensive distribution, ranging from southern Ontario and central New York south to North Carolina and Virginia, and west to Illinois ( Taylor and Schuster 2004).Given thisextensive range, Cambarus robustus likely represents a species complex.Floodplain Cambarus robustus were collected from the Upper Ohio North and Middle Ohio North basins (Figure 10), but has also been collected in the Middle Ohio South and Lower Ohio drainages outside the floodplain (Z. J. Loughman, unpublished data). Jezerinac et al. (1995) collected Cambarus robustus from Harman Creek, Brooke County, in the northern panhandle. The only other northern panhandle location where the species was collected in was the Fish Creek system in Marshall County. Loughman et al. (2009) commented on this disjunct distribution and hypothesized that it could be the result of separate postglacial invasions. Most Cambarus robustus populations present along the floodplain occur in the Middle Ohio North basin (60% of streams).

Cambarus robustus was likely under surveyed during this effort. This species prefers free-flowing streams more similar to mainstem rivers rather than habitats associated with big river confluences like those sampled in this survey.

Morphometrics.

The largest individual collected was a 46.6 mm TCL form II male collected in Kings Creek, Hancock County. The largest female was also taken there and was 36.0 mm TCL. Mean Cambarus robustus TCL was 33.0 mm (n = 20, SE = 5.5). Morphometric data are presented in Table 5.

Habitat and natural history.

Cambarus robustus (Figure 11) inhabits 3rd through 5th ordered streams that dissect the floodplain. Preferred microhabitats included leaf packs, boulder fields, and spaces beneath large slab boulders. Cambarus robustus observed in Ben’s Run burrowed into hardpan substrates of pools, and readily used available leaf packs. Many individuals eluded capture in this stream, but were observed resting at the entrances to these burrows. No Cambarus robustus were collected from headwater streams in this effort. Crayfish associates included Cambarus carinirostris , Cambarus bartonii cavatus , and Orconectes obscurus . Seasonal data for Cambarus robustus are presented in Table 3.

Conservation status within study area.

Cambarus robustus populations along the floodplain are stable and do not warrant special attention.