Rostrum broad, margins thickened and parallel, terminating in a 90° angle cephalically to form acumen; acumen consisting of a single upturned spiniform tubercle; median carina absent in floodplain populations; postorbital ridges truncate, cephalic margin with a weak tubercle; cephalothorax slightly flattened dorsoventrally in profile; 2–5 punctations across narrowest region of areola; branchiostegal region moderately punctate, with small tubercles; chelae broad and robust; mesial surface of palm with a single row of 5–7 adpressed tubercles; two prominent subpalmar tubercles present; enlarged 3rd tubercle on mesial surface of fixed finger of propodus; first form gonopods contiguous at base, with 2 terminal elements bent 90° to base; central projection with subapical notch; total length of central projection equal to length of mesial process; mesial process bulbous, truncating distally; second form gonopod non-corneous and blunt; annulus ventralis rhomboid in shape, embedded shallowly in sternum and movable.

Carapace dorsally brown, beige, or pink; rostrum margins red to reddish brown; chelae olivaceous green to brown; dactyl and propodus tubercles cream or yellow; pereiopods white, cream, or yellowish gray, rarely light blue; abdomen terga dorsally brown or beige, bordered in crimson; ventral surfaces cream or white.

Cambarus carinirostris were collected from four counties at eight locations. Localities and demographics are listed below.

BROOKE COUNTY: Cross Creek at entrance to Bruin Drive adjacent to Brooke High School, 40.306442, -80.5997; 4 September 2005 – (WLU 05090401), 2 II♂. RT 2 crossing of nameless tributary 2.27 km (1.41 mi) S of Beech Bottom, 40.23163 N / 80.6523 W; 28 June 2005 – (WLU 05072801), 2 II♂. HANCOCK COUNTY: Hardin Run 0.81 km (0.5 mi) from CR 2-7/RT 2 intersection on CR 2-7, 40.533314, -80.60326; 23 August 2005 – (WLU 0508230), 1 I♂, 2 II♂, 2 ♀. MARSHALL COUNTY: Boggs Run at RT 2 crossing, 40.02481 N / 80.72577 W; 28 July 2005 – (WLU 05072801), 1 II♂, 1♀. Long Run at Long Run/Fish Creek confluence, 39.805878, -80.8052; 20 July 2005 – (WLU 05072002), 3 ♀. Nameless tributary at RT 2 crossing adjacent to Columbia Chemical operations, 39.85933, -80.79305; 28 July 2005 – (WLU 05072803), 6 I♂, 1 ♀. WETZEL COUNTY: Proctor Creek at RT 2 crossing, 39.70037, -80.81791; 9 July 2008 – (WLU 08070901), 5 II♂, 1 ♀. RT 2 crossing of nameless tributary at Marshall/Wetzel County line, 39.720192, -80.82281; 20 July 2005 – (WLU 05072001), 1 II♂.

Cambarus carinirostris ranges from central West Virginia north through the Monongahela River system in West Virginia and Pennsylvania and the Allegheny River system in Pennsylvania and New York (Thoma and Jezerinac 1999).The western extent of Cambarus carinirostris is the Flushing escarpment in eastern Ohio (Thoma and Jezerinac 1999). Cambarus carinirostris were collected only from the northern basins along the floodplain, including Upper Ohio North, Upper Ohio South, and Middle Ohio North (Figure 6). Within the Middle Ohio North basin it was collected in the extreme northern regions of the basin. The southern limit of this species’ range in the floodplain is Proctor Creek, Wetzel County. Cambarus (Cambarus) bartonii cavatus Hay, 1902 replaces this species in Fishing Creek. The distribution of Cambarus carinirostris is the same as reported by Jezerinac et al. (1995).

Figure 6.

Cambarus carinirostris and Cambarus bartonii cavatus distribution along the West Virginia portion of the Ohio River floodplain

Cambarus carinirostris is a moderate sized crayfish. Mean TCL was 29.1 mm (n = 29, SE = 5.61). The largest individual was a form I male with a TCL of 39.4 mm collected from Holbert Run in Hancock County. The largest female was also collected from Holbert Run, and had a TCL of 32.1 mm. Morphometric data for Cambarus carinirostris is presented in Table 2.

Cambarus carinirostris (Figure 7) inhabits lotic water bodies, with a preference for headwater streams (Jezerinac et al. 1995; Thoma and Jezerinac 1999). Most specimens collected along the floodplain were taken in first and second order streams. Within these environments, Cambarus carinirostris frequented spaces beneath slab boulders, large boulders, and various substrate debris. When the substrate permits, Cambarus carinirostris constructs burrow networks in the stream bank (Jezerinac et al. 1995; Loughman et al. 2009); however, no Cambarus carinirostris were collected from burrows in this study. Loughman et al. (2009) found that Cambarus carinirostris likely created the majority of stream bank burrows in northern West Virginia, given the scarcity of other burrowing species in northern portions of the floodplain.

Figure 7.

Cambarus carinirostris, Upper Ohio South basin, Ohio County, West Virginia – WLU 05072002

Cambarus carinirostris also was collected from larger streams, where it inhabits side pools, eddies, and stream margins. The species appears to be limited to marginal habitats in larger ordered streams through competitive exclusion with larger, more aggressive species such as Orconectes obscurus (Hagen, 1870), and Cambarus robustus Girard, 1852, both of which were collected with Cambarus carinirostris. Seasonal data for Cambarus carinirostris are presented in Table 3.

Cambarus carinirostris populations along the floodplain are stable and do not warrant special conservation action.

Rostrum broad; margins reduced, subparallel, terminating cephalically in a gentle angle to form acumen; anterior region of rostrum excavated; acumen consisting of a single upturned spiniform tubercle; postorbital ridges truncated, cephalic margin with weak tubercle; cephalothorax oval shaped and slightly dorsoventrally flattened in profile; 2–3 punctations across narrowest region of areola; branchiostegal region moderately punctate, with small tubercles; chelae broad and robust; mesial surface of palm consisting of two rows of defined tubercles; first row with 5–8 rounded tubercles; second with 3–4 tubercles; two prominent subpalmar tubercles present; first form gonopods contiguous at base, with 2 terminal elements bent 90° to the base; central projection with shallow subapical notch; total length of central projection equal to mesial process length; second form gonopod non-corneous and blunt; mesial process bulbous, truncating distally; annulus ventralis rhomboid in shape, embedded shallowly in sternum and movable.

Carapace dorsally olivaceous brown, beige, or tan; rostrum margins chestnut brown to brown; chelae olivaceous green to brown; dactyl and propodus denticles cream or yellow; pereiopods tan, light green, cream, or gray; abdomen terga dorsally brown or beige, bordered in gray; ventral surfaces cream or white.

Cambarus bartonii cavatus were collected from six counties at 15 locations. Collection locales and demographics are listed below.

JACKSON COUNTY: Flooded field adjacent to RT 33 S, 9.72 air km (6.04 mi) N of Ravenswood, 39.04274, -81.7827; 3 April 2005 – (WLU 05040301), 3♀. Little Sandy Creek, at intersection of RT 68/CR 8, 38.991497, -81.761765; 21 July 2006 – (WLU 06012103), 1 II ♂. Vernal pool complex adjacent to railroad tracks 3.56 km (2.21 mi) N of Ravenswood, 39.09015, -81.79469; 3 April 2005 – (WLU 05040302), 1♀. West Creek, at intersection of CR 12 /CR 10, 38.924362, -81.94200; 20 July 2006 – (WLU 06072001), 1 II ♂, 1♀. MASON COUNTY: Pin oak swamp adjacent to Point Pleasant Moose Lodge in Wagner, 38.833603, -82.12227; 6 June 2005 – (WLU 05060601), 2 ♀. Roadside ditch adjacent to RT 2, 9.17 km (5.7 mi) S of Point Pleasant, 38.80469, -82.18821; 4 March 2005 – (WLU 05030401), 2 I♂, 1 ♀. Roadside ditch adjacent to RT 2 N, 2.91 km (1.81 mi) N of Clover, 38.589428, -82.19548; 4 March 2005 – (WLU 05030402), 1 ♀. Roadside ditch adjacent to RT 2 N, 1.93 km (1.2 mi) N of Glenwood, 38.58816, -82.201004; 3 April 2005 – (WLU 05040305), 1 I♂, 2 ♀. Roadside ditch adjacent to RT 2 N 0.90 air km (0.56 mi.) N of Hogsett, 38.70056, -82.17708; 17 March 2005 – (WLU 05031707), 1 ♀. PLEASANTS COUNTY: Middle Island Creek at RT 2 crossing, 39.40328, -81.197624; 21 July 2006 – (WLU 06072104), 1 ♀. TYLER COUNTY: Nameless tributary at RT 2 crossing in Friendly, 39.513386, -81.06285; 28 July 2005 – (WLU 05072806), 1 I♂, 1 ♀. WETZEL COUNTY: Doolins Run at RT 2 crossing, 39.639576, -80.85607; 28 July 2005 – (WLU 05072805), 1 II♂. WOOD COUNTY: Big Run at CR 21-1 crossing, 39.364048, -81.45656; 21 July 2004 – (WLU 06072101), 1 ♀. Boaz Swamp Wildlife Management Area, 39.462868, -81.10855; 12 April 2004 – (WLU 04042101), 1 ♀. Nameless tributary crossing 3.54 km (2.2 mi) S of Parkersburg, 39.05142, -81.742836; 21 July 2006 – (WLU 06072106) 1 II♂, 1 ♀.

Cambarus bartonii cavatus ranges from northern Georgia and Tennessee through eastern Kentucky, east central Ohio and western Virginia (Taylor and Schuster 2004). In West Virginia Cambarus bartonii cavatus is prevalent throughout basins associated with the lower reaches of the Kanawha system west of Kanawha Falls and basins draining into the Big Sandy River system. Cambarus bartonii cavatus floodplain populations inhabit the Middle Ohio North, Middle Ohio South, and Lower Ohio basins, and are the dominant secondary burrowing species inhabiting the floodplain (Figure 6). It is replaced in the Middle Ohio North basin in Proctor Creek with Cambarus carinirostris. A specimen collected from Doolin Run, Wetzel County, a tributary to Fishing Creek, represents the northernmost collection of this species in West Virginia. The distribution of this species has not changed since Jezerinac et al.’s (1995) survey in the late 1980’s.

Cambarus bartonii cavatus is a medium to large crayfish. The largest individual collected was a female with a 51.6 mm TCL taken from an ephemeral pool complex 3.6 km north of Ravenswood, Jackson County. The largest male collected was a form I collected from a roadside ditch 1.9 km north of Glenwood, Mason County, with a TCL of 45.6 mm. Mean Cambarus bartonii cavatus carapace length was 34.4 mm (n = 25, SE = 12.42) . Morphometric data for Cambarus bartonii cavatus is presented in Table 4.

Cambarus bartonii cavatus (Figure 8) is a secondary burrowing species like Cambarus carinirostris, (Jezerinac et al. 1995). Along the floodplain, it utilized first and second order stream habitats, ephemeral wetlands, and roadside ditches (Figure 9). The species demonstrated a preference for roadside ditches, with 42.1% of individuals taken from this habitat. Ditches with an associated first-order stream produced particularly robust populations.

Figure 8.

Cambarus bartonii cavatus, Lower Ohio basin, Cabell County, West Virginia– WLU 05031707

Figure 9.

Glenwood, Mason County – Roadside Ditch Cambarus bartonii cavatus and Cambarus thomai utilized roadside ditches readily; these habitats proved important for floodplain crayfish populations. Additional species observed utilizing roadside ditches included Fallicambarus fodiens and Procambarus acutus acutus.

Within lotic systems, Cambarus bartonii cavatus prefers first through third order streams to larger streams. It burrows extensively in stream banks, particularly those composed of hardpan and similar regoliths. Burrows are intricate, with central shafts ranging in depth from 0.3 m to 1.0 m. At the terminus of the central shaft, enlarged chambers were always present with several branching auxiliary tunnels. One marked difference between Cambarus bartonii cavatus burrows and those of other burrowing species is the width of the central shaft and the dimensions of the central resting chamber.

The central shaft and central chamber of other floodplain burrowing species (e.g., Cambarus thomai Jezerinac, 1993, Fallicambarus fodiens (Cottle, 1863), were the width of the crayfish’s carapace at the widest point. Cambarus bartonii cavatus burrows did not follow this same pattern and, usually, were wide and oblong. Anecdotally, Cambarus bartonii cavatus burrows were readily identified by the presence of these structural components, but this method of identification was not used to definitively verify Cambarus bartonii cavatus presence at a site.

In late winter females comprised 66% of trap captures. Those captured in late winter/early spring all possessed active glair glands. This condition has been used in previous studies to indicate future egg extrusion and is likely the explanation for this increase in female activity (Hobbs 1981). No ovigerous females were collected during this study. Jezerinac et al. (1995) reported ovigerous specimens in West Virginia in July. A female retained in captivity collected in a roadside ditch 2.91 km north of Clover extruded eggs on 18 May 2005. Males captured in late winter/early spring did not show any trend toward any single demographic group, with an equal number of form I and form II individuals captured. Crayfish associates collected with Cambarus bartonii cavatus included Cambarus robustus, Cambarus thomai, Fallicambarus fodiens, Orconectes obscurus, Orconectes sanbornii (Faxon, 1884), Orconectes virilis and Procambarus acutus. Seasonal data for Cambarus bartonii cavatus are presented in Table 3.

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

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.

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.

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 ♀.

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).

Figure 10.

Cambarus robustus, Orconectes rusticus and Orconectes virilis distribution along the West Virginia portion of the Ohio River floodplain.

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.

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.

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.

Figure 11.

Cambarus robustus, Upper Ohio North basin, Hancock County, West Virginia – WLU 05101701

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

Rostrum slightly broad, margins converging to form acumen terminating in single reduced, upturned tubercle; postorbital ridges reduced, rarely terminating in small tubercle; cephalothorax dorsolaterally compressed in profile and vaulted; areola obliterated; branchiostegal region devoid of tubercles; chelae robust and diamond shaped; mesial surface of palm with disorganized prominent tubercles, mesialmost tubercles serrate; basiodactyl row consisting of 5–9 reduced rounded tubercles; first form male gonopods contiguous, with 2 terminal elements bent 90° to the shaft; central projection truncated distally and lacking sub-apical notch; total length of central projection equal to mesial process length; mesial process short, truncating distally; second form gonopod non-corneous and blunt; annulus ventralis rhomboid in shape with deep “S” shaped sinus, embedded shallowly in sternum, and movable.

Carapace dorsally brown, light green, olive, light blue, or blue grey; rostrum margins orange or red; chelae body light green, light brown, or blue; propodus light blue or light green; dactyl and propodus denticles cream or yellow; pereiopods tan, light green, cream, or gray; abdomen body light green, light blue gray or brown; tubercles covering chelae light yellow, cream, or orange; two light dorsal stripes present on dorsal surface of abdomen; ventral surface cream or white.

Cambarus thomai were collected from eight counties at 26 localities, listed below.

CABELL COUNTY: Green Bottom Swamp at Hoeft Marsh Wildlife Management Area, 38.58616 N / 82.24878 W; 2 April 2009 – (WLU 09040201), 2 I♂. HANCOCK COUNTY: Tomlinson Run backwater at RT 2 crossing, 40.54026, -80.628075; 30 March 2006 – (WLU 06033001), 3 I♂. JACKSON COUNTY: Flooded field adjacent to RT 33 S, 9.72 air km (6.04 mi) N of Ravenswood, 39.04274, -81.7827; 18 March 2005 – (WLU 05031803), 7 I♂, 3 O♀. Vernal pool complex adjacent to railroad tracks 3.56 km (2.21 mi) N of Ravenswood, 39.09015, -81.79469; 3 April 2005 – (WLU 05040302), 3 I♂, 1 II♂. MASON COUNTY: Ditch adjacent to RT 2 N, 1.77 km (1.10 mi) N of Rt 2 railroad crossing in Ashton, 38.63165, -82.16464; 18 March 2005 – (WLU 05031805), 3 I♂, 1 II♂. Krodel Park marsh adjacent to Fort Randolph reproduction, 38.785404, -82.12209; 5 March 2005 – (WLU 05030502), 4 I♂. Maple swamp adjacent to RT 2 railroad crossing in Ashton, 38.622005, -82.16758; 26 March 2004 – (WLU 04032601), 18 I♂, 2 ♀; 30 March 2004 – (WLU 04033001), 6 I♂, 3 O♀, 1 ♀; 28 April 2004 – (WLU 04042801), 4 I♂, 1 O♀, 2 ♀; 18 March 2005 – (WLU 05031805), 2 I♂. Pin oak swamp adjacent to Point Pleasant Moose Lodge in Wagner, 38.833603, -82.12227; 26 March 2004 – (WLU 04032601), 3 I♂; 12 April 2004 – (WLU 04041205), 3 I♂, 2 O♀. Red-Osier Dogwood swamp adjacent to RT 33 S in Hartford, 39.008915, -81.99847; 5 March 2005 – (WLU 05030504), 1 I♂. Roadside ditch adjacent to RT 2 N, 2.91 km (1.81 mi) N of Clover, 38.589428, -82.19548; 4 March 2005 – (WLU 05030402), 3 I♂. Roadside ditch adjacent to RT 2, 9.17 km (5.7 mi) S of Point Pleasant, 38.80469, -82.18821; 12 April 2004 – (WLU 04041206), 6 I♂. Roadside ditch adjacent to RT 2 N, 0.22 air km (0.14 mi) N of Hogsett, 38.694496, -82.1765; 17 March 2005 – (WLU 05031707), 5 I♂. Roadside ditch adjacent to RT 2 N 0.90 air km (0.56 mi.) N of Hogsett, 38.70056, -82.17708; 17 March 2005 – (WLU 05031707), 4 I♂, 1 II♂. Roadside ditch adjacent to RT 2 N 1.93 km (1.2 mi) N of Glenwood, 38.58816, -82.201004; 3 April 2005 – (WLU 05040305), 1 I♂. Roadside ditch adjacent to RT 62 N, 0.34 km (0.21 mi) N of Hallwood, 38.97562, -82.081314; 17 March 2005 – (WLU 05031706), 1 I♂. Roadside ditch adjacent to RT 62 S at Mountaineer Power Plant, 38.974934, -81.94418; 5 March 2009 – (WLU 05030509), 2 I♂. Slough adjacent to RT 33 N in Mason, 39.00983, -82.03899; 5 March 2005 – (WLU 05030505), 1 I♂; 17 March 2005 – (WLU 05031704), 6 I♂, 4 ♀. Vernal pool complex at RT 2/Lighthouse Gospel Church Road intersection, 38.82201, -82.13136; 17 March 2005 – (WLU 05031707), 2 I♂, 2 O♀. PLEASANTS COUNTY: Ohio River embayment 4.03 air km (2.52 mi) S of St. Mary’s, 39.397575, -81.202415; 12 April 2004 – (WLU 05030506), 1 II♂, 1 OF. Vernal pool adjacent to RT 2 N across from Cytec Community Fishing Area, 39.347824, -81.32024; 5 March 2005 – (WLU 04041203), 2 I♂. TYLER COUNTY: Maple swamp adjacent to RT 2 S in Friendly, 39.50822, -81.06736; 20 March 2004 – (WLU 04032001), 2 I♂. WETZEL COUNTY: Maple Swamp adjacent to RT 2 S in New Martinsville, 39.32582, -80.866234; 2 April 2004 – (WLU 04040201), 8 I♂, 2 ♀; 21 March 2006 – (WLU 06032104), 3 I♂, 1 II♂. (23.) Ohio River backwater at Marshall/Wetzel County line, 39.717846, -80.514959; 2 April 2004 – (WLU 04040203), 2 I♂; 21 March 2006 – (WLU 06032101), 3 I♂. WOOD COUNTY: Bellville Wildlife Management Area 4.03 km (2.50 mi) S of Bellville, 39.132915, -81.730865; 5 March 2005 - (WLU 05030507), 6 I♂. Boaz Swamp Wildlife Management Area, 39.462868, -81.10855; 25 March 2004 – (WLU 04032501), 1 I♂; 12 April 2004 – (WLU 04041203), 2 I♂, 1 O♀; 5 March 2005 – (WLU 05030509), 1 I♂. Lee Creek at CR 11 crossing, 39.153275, -81.73507; 2 April 2004 – (WLU 04040203), 2 I♂.

Cambarus thomai is the largest burrowing crayfish occurring in West Virginia, and the most frequently collected species in this study. The largest individual collected was a form I male, 53.6 mm TCL from Bellville, Wood County. The largest female measured 38.6 mm TCL and was collected from a flooded field 1.1 km north of Ravenswood, Jackson County. Mean Cambarus thomai carapace length was 37.0 mm (n = 148, SE = 5.41). Morphometric data for Cambarus thomai are presented in Table 6.

Cambarus thomai distribution includes western Pennsylvania, central and eastern Ohio, central and western West Virginia and eastern Kentucky (Taylor and Schuster 2004). (Ortmann (1905a, 1906) was the first to mention the presence of Cambarus thomai (= Cambarus diogenes Girard, 1852) in Brooke and Hancock counties, stating that populations persisting in both counties were stable. Newcombe (1929) documented the species in Hancock and Brooke counties, and like Ortmann, identified the species as Cambarus diogenes. Jezerinac described Cambarus thomai in 1993 based on material from West Virginia in his description (Jezerinac 1993), but. questioned the validity of Newcombe’s records. Jezerinac (1993) found northern Cambarus thomai populations problematic, specifically those occurring in Brooke County. This study did not collect any specimens from Brooke County, but specimens were collected in Tomlinson Run Backwater, validating previous records for Hancock County. Cambarus thomai was not taken in Brooke County during this study, but has been collected recently from portions of the county not associated with the floodplain.

Cambarus thomai was collected from the Upper Ohio North, Middle Ohio North, Middle Ohio South, and Lower Ohio basins (Figure 12). Specimens from Jackson County, Middle Ohio South basin, represent county records. It is absent from the Upper Ohio South basin and occurs again in the Upper Ohio North basin (Figure 12). Within the Upper Ohio North, Cambarus thomai was collected, but not in large numbers. Cambarus thomai populations enter the Upper Ohio North basin from the Tuscarawas River in Eastern Ohio. Different soil types are found in the Upper Ohio North and South basins, which could explain the species’ distribution. Another possibility controlling Cambarus thomai distribution is the increased agricultural land use practices and declining riparian habitat that has sharply increased in the Upper Ohio South and North basins.

Figure 12.

Cambarus thomai distribution along the West Virginia portion of the Ohio River floodplain

In the Middle Ohio North, Middle Ohio South, and Lower Ohio basins, Cambarus thomai is stable. Mason County contains substantial Cambarus thomai populations, with the species documented at every site (n = 18) sampled in the county. Populations decline north of these basins. The most substantial northern population occurs in New Martinsville, Wetzel County. Ortmann (1906) commented on this population based on surveys in the late 1800’s, noting how numerous burrows were in “bottomlands” adjacent to the Ohio River.

Cambarus thomai (Figure 13) was the most frequently collected burrowing crayfish along the Ohio River floodplain. Marshes, swamps, embayments, wet fields, ephemeral pools, ponds, roadside ditches, and bottomland forests are habitats utilized by Cambarus thomai. Population density appears to be directly correlated with mature forest canopies, with a preference for ephemeral pool systems, bottomland forests, and marsh habitats.

Figure 13.

Cambarus thomai, Middle Ohio South basin, Mason County. Amber – WLU 04032601 (A.) and blue–green - WLU 04032605 (B.) colorphases. This species is the most prevalent crayfish along the Ohio River floodplain and constructs intricate burrows in lentic habitats in the Upper Ohio South, Middle Ohio North and South, and Lower Ohio basins.

Population densities decline in exposed agricultural fields. The species responds negatively to livestock even when adequate habitat is available. These pasture habitats exhibit soil compaction, excess nutrients, and low browse lines. A lack of vegetation possibly expedites drawdown conditions with increased levels of evapotranspiration. Exposed conditions and frequent manipulation of topsoil appear to limit Cambarus thomai density in agricultural settings.

Cambarus thomai uses surface waters during late-winter and early-spring. During all other seasons it was collected from burrows, which are complex, with a 0.3 m to 1.5 m deep central shaft ending in a resting chamber. Central shafts often have multiple ancillary tunnels prior to the resting chamber. Resting chambers also possess additional tunnels, particularly from their floors. Vegetation was frequently found in these auxiliary tunnels. In many instances a short 10–20 cm central shaft bifurcates into two complete central shafts, each ending in its own central chamber. Chimneys often were associated with these burrows (Figure 14).

Figure 14.

Cambarus thomai chimney, Middle Ohio North basin, Wetzel County, West Virginia. Cambarus thomai chimneys were numerous throughout the southern regions of the floodplain. The chimney pictured measured 18 cm in height and 10 cm in diameter.

Cambarus thomai were nocturnal, and displayed stylized behaviors while resting in their burrow portals. They rest with their antennae held laterally and their chelae barely breaching the burrow’s entrance. If pressure pulses are sent through the soil, they orient their antennae toward the pulse without shifting body position. If pulses continued, crayfish either retreated into their burrows or left their burrow’s to investigate the pulse source. The majority of Cambarus thomai observations at burrow portals occurred in June and July. During late winter and early spring, several form I males and ovigerous females were observed nocturnally cruising and feeding on periphyton in ephemeral pools.

As stated previously, February through April, Cambarus thomai uses surface waters extensively. Eighty-six percent of trap captures were form I males. Ovigerous females (n = 12) also used surface waters, with 50% of females captured at this time carrying eggs. Linear regression analysis of ovigerous females indicates there is not a strong relationship between carapace length and the number of pleopodal eggs (Figure 15). Egg counts ranged from 108–304 eggs per female. Pleopodal egg diameter ranged from 1.51–2.47 mm, with a mean diameter of 2.09 mm.

Figure 15.

Relationship between carapace length and pleopodal egg number in Cambarus thomai

Given the high percentage of ovigerous females captured in late winter and early spring, mating likely occurs in the fall. Females carry sperm throughout the winter and extrude eggs in early spring when ephemeral pool hydroperiods are at their most active. Instars are carried by females throughout the spring, and released at the beginning of the summer season. This life history strategy enables neonates to mature throughout the summer and enter their first winter as juveniles. Jezerinac et al. (1995) collected ovigerous females in March, April, May, and June in West Virginia, and Taylor and Schuster (2004) collected a single ovigerous female in Kentucky in March. Our results validated previous seasonal data for Cambarus thomai as presented in Table 3.

Cambarus thomai neonates used surface waters throughout the summer season (May–September) and were the only demographic observed at this time. Dip netting yielded large numbers of young-of-the-year in July and August; however, whether neonates remain in surface waters may depend on water availablility throughout the fall into winter. During drawdown in several sites in Mason County, juveniles were observed burrowing.

Neonate utilization of surface waters may be a dispersal mechanism to enable colonization and equally distribute individuals throughout wetlands or redistribute individuals into areas of high productivity. Nocturnal searches found Cambarus thomai utilizing surface waters rather than relying on burrows. On several occasions individuals would seek cover under substrate debris in surface waters although burrows were readily available.

Cambarus thomai populations are stable within the Middle Ohio North, Middle Ohio South and Lower Ohio basin. Additional survey efforts are needed in the Upper Ohio North and Upper Ohio South basins to determine the status of northern populations.

Rostrum slightly broad and moderately excavated, deflected ventrally; margins converging to form acumen cephalically with reduced upturned tubercle; postorbital ridge reduced, not terminating in tubercle; cephalothorax dorsolaterally compressed in profile and vaulted; areola obliterated; branchiostegal region devoid of tubercles; chelae diamond shaped; mesial surface of palm with 2 distinct rows of tubercles; dorsalmost row consisting of 6–9 serrate tubercles; second row consisting of 3–6 circular tubercles; basiodactyl row consisting of 5–7 punctations; opposable surface of dactyl with distinct basal notch; junction of dactyl and propodus setiferous; first form gonopods basally contiguous, with 2 terminal elements bent 90° to shaft; central projection of populations on the floodplain possessing distinct subapical notch; total length of central projection equal to mesial process length; mesial process bulbous, truncating distally; second form gonopod non-corneous and blunt; subapical notch absent in second form gonopod; annulus ventralis rhomboid in shape with deep S-shaped sinus and C-shaped fossa; embedded shallowly in sternum, and movable.

Carapace dorsally and laterally tan, brown, reddish brown, or gray; cephalic and branchial region mottled with black or deep grey spots; chelae tan, deep gray, or gray brown; tubercles on chelae cream or light gray; distal region of dactyl and propodus increasingly orange; perieopods green or light grey; abdomen grey or olivaceous brown, with 2 distinct dorsal stripes; ventral surfaces cream or white.

Fallicambarus fodiens were collected from two counties at three locations in the current study, as listed below.

CABELL COUNTY: Green Bottom Swamp at Hoeft Marsh Wildlife Management Area, 38.58616, -82.24878; 2 April 2009 – (WLU 09040201), 2 I♂, 2 II♂, 1 O♀, 4♀. MASON COUNTY: Vernal pool complex at RT 2/Lighthouse Gospel Church Road intersection, 38.82201, -82.13136; 17 March 2005 – (WLU 05031707), 1 I♂, 1 ♀; 28 March 2005 – (WLU 05032801), 1 I♂, 3 ♀. Pin oak swamp adjacent to Point Pleasant Moose Lodge in Wagner, 38.833603, -82.12227; 26 February 2004 – (WLU 04022601), 1 II♂, 1 O♀; 26, March 2004 – (WLU 04032601), 3 I♂, 2 ♀; 30 March 2004 – (WLU 04033001), 1 I♂; 12 April 2004 – (WLU 04041202), 1 I♂; 28 April 2004 – (WLU 04042801), 1 II♂, 2 ♀.

Fallicambarus fodiens is a wide-ranging species occurring along the Atlantic Slope in Maryland, Virginia, and North Carolina east to the Ohio and Mississippi river valleys excluding the majority of the Appalachian Mountains. Northern populations occur along the Great Lakes and in southern Ontario (Jezerinac et al. 1995). Fallicambarus fodiens were collected from the Lower Ohio Basin and Middle Ohio South Basin (Figure 16). Within the Middle Ohio South, all populations were within one km of the Middle Ohio South/Lower Kanawha basin border. Two previously unknown populations were discovered in Mason County including one adjacent to the Point Pleasant Moose Lodge in Wagner and another in Krodel Park, Point Pleasant. Increased efforts to find this species along the floodplain throughout the Middle Ohio South, Middle Ohio North and Lower Ohio basins were futile.

Figure 16.

Fallicambarus fodiens and Procambarus acutus distribution along the West Virginia portion of the Ohio River floodplain

Jezerinac and Stocker (1987) theorized that Fallicambarus fodiens populations in West Virginia were Marietta River relicts. Currently, the Marietta River Valley is composed of the Kanawha River Valley. This hypothesis does help explain the scarcity of this species along the floodplain. Future survey efforts for Fallicambarus fodiens should focus on wetlands associated with the Kanawha River floodplain. The Moose Lodge wetland and its associated wetlands include that floodplain, which is 0.8 km from the Kanawha River and Ohio River confluence. The Moose Lodge wetland is composed of diverse bottomland forest with multiple ephemeral pools, which possess stable Fallicambarus fodiens populations. Habitat specialization may explain low Fallicambarus fodiens numbers elsewhere since little mature bottomland forests remain along the Ohio River floodplain. Apparently this habitat is needed for West Virginia’s disjunct population of Fallicambarus fodiens to persist.

Several animals were observed, but not disturbed due to the rarity of this species in West Virginia. The largest individual was a 40.1 mm TCL form I male collected at the Moose Lodge wetland, Mason County. The largest female collected was 37.3 mm TCL from an ephemeral pool complex located inside Krodel Park, Mason County. Mean carapace length for this species was 34.3 mm (n = 26, SE = 8.67). Morphometrics data for Fallicambarus fodiens is presented in Table 7.

Figure 17.

Fallicambarus fodiens, Middle Ohio South basin, Mason County, West Virginia - WLU 05031707

Fallicambarus fodiens (Figure 18) in West Virginia is an ephemeral pool specialist. Within these ecosystems, colonies were associated with either lowland forest environments or open, wet fields. Similar habitat preferences for this species has been observed across its range (Guiasu 2007; Norrocky 1991; Taylor and Schuster, 2004). With the exception of the Greenbottom Swamp population, ephemeral systems are preferred over larger, more permanent water bodies. Fallicambarus fodiens colonies typically consist of 5–10 burrows for every 1 m2 of substrate. Within these colonies, the sex ratio of captured individuals was 1:1 male to female. Fallicambarus fodiens burrow morphology is simple, with the majority of excavated burrows consisting of a central shaft ranging in depth from 0.3 m to 1.0 m. One or two short ancillary tunnels often were present radiating from central shafts. These ancillary tunnels often are full of debris. Resting chambers usually were present at the terminus of these shafts, with either few or no ancillary tunnels radiating from them.

Figure 18.

Ovigerous Fallicambarus fodiens, Middle Ohio South basin, Mason County, West Virginia. Ovigerous females were prevalent in surface waters from late February through early March. Females with pleopodal instars were observed from mid March through early May. The pictured specimen was released after capture.

Several Fallicambarus fodiens females (n = 7) were collected carrying instars and eggs in February and March 2004 and 2005 (Figure 18). Egg extrusion along the floodplain occurred throughout the months of February and March. By early April, females were carrying first stage instars, with 4th stage instars observed by late April. Jezerinac et al. (1995) also observed ovigerous females in February and March in West Virginia. Ovigerous females have been collected February through April in Illinois (Page 1985), Kentucky (Taylor and Schuster 2004), and Michigan (Creaser 1931). All adult males captured during this study were form I. Given that females were ovigerous in early spring and males enter the winter season as form I, mating in this species likely occurs in the fall or winter along the floodplain.

Fallicambarus fodiens females carrying instars were observed nocturnally foraging in open water on 18 March 2004 and 4 April 2009 in Greenbottom Wildlife Management Area. Several individuals (n = 8) were resting or grazing at their burrow entrances on periphyton that had colonized submerged canary grass (Phalaris canariensis L.). Within the colony burrows were flooded by 15–30 cm of standing water. Instars were observed leaving burrow entrances to graze. Upon provocation, disturbed females stopped moving long enough to allow instars to reattach to their abdomens, then retreated to their burrows. Seasonal data for Fallicambarus fodiens is presented in Table 3. Crayfish associates collected with Fallicambarus fodiens include Cambarus bartonii cavatus, Cambarus thomai, Orconectes virilis, and Procambarus acutus acutus.

Fallicambarus fodiens warrants conservation attention and is deserving of S1 status. Surveys are needed along the Kanawha River in wetland habitats to determine if this species persists there. Along the floodplain threats to this species’ survival include land use practices and their associated pollutants, hard surface run off, and destruction of bottomland forests.

Rostrum with slightly converging margins, not thickened, with marginal spines or tubercles; median carina absent; postorbital ridges possessing a sharp spine. Cephalothorax ovoid, slightly, dorsoventrally compressed, without setae. Areola 3.7–6.6 times longer than wide, comprising 27–39% of TCL, with 2–3 rows of punctations across narrowest region; cervical groove interrupted just above cervical spine; lacking hepatic spines; suborbital angle obsolete. Antennal scale about 1.5 times as long as wide; basiopodite spine of antenna well developed. Ischiopodite of antenna without spine. Chelae smooth, broad and robust, length 91% of TCL; mesial surface of palm consisting of two well developed rows of tubercles; mesialmost row consisting of 7–11; dorsolateral row with 5–11; lateral margin of propodus smooth, dorsal surfaces of both dactyl and fixed finger of propodus with weak dorsolateral ridges; some elongate setae at base of fixed finger. First form gonopods short, comprising 33% of TCL, with two terminal elements about equal length; corneous central projection comprising 23% of pleopod length, tapering distally to point; mesial process non-corneous, spatulate, partially surrounding central projection; cephalic base of central projection with right angle shoulder. Form two male gonopod non-corneous, blunt, shoulder not prominent or absent. Female annulus ventralis deeply embedded in sternum, moveable, wider than long, cephalolateral prominences well developed, distinctly separated by a trough; fossa rather deep, sinus sinuate in caudal 67% of annulus.

Carapace, abdomen and dorsal surface of chelae brown; rostral margins, caudal edge of carapace, and anterodorsal surface of terga dark brown; tips of chelae and knob at base of dactyl orange; tubercles on mesial and lateral margins of dactyl, mesial margin of palm, and mesial margin of propodus, and two spines or tubercles on anterodorsal surface of carpus yellow; reddish stripe on lateral margin of chelae; ventral margins beige.

Orconectes obscurus were collected from six counties at 16 locations in the current study, as listed below.

BROOKE COUNTY: Buffalo Creek at RT 2 crossing in Wellsburg, 40.261375, -80.61508; 4 September 2005 – (WLU 05090402), 2 I♂, 3 ♀. Cross Creek at entrance to Bruin Drive adjacent to Brooke High School, 40.306442, -80.5997; 28 June 2005 – (WLU 05062803), 1 ♀; 4 September 2005 – (WLU 05090403), 2 I♂, 1 II♂, 2 ♀. (3.) RT 2 crossing of nameless tributary 2.27 km (1.41 mi) S of Beech Bottom, 40.23163, -80.6523; 28 June 2005 – (WLU 05062801), 4 II♂. RT 2 crossing of nameless tributary in Beech Bottom proper, 40.306442, -80.5997; 28 June 2005 – (WLU 05062801), 1 ♀. HANCOCK COUNTY: Hardin Run 0.81 km (0.5 mi) from CR 2-7/RT 2 intersection on CR 2-7, 40.533314, -80.60326; 23 August 2005 – (WLU 05082302), 2 I♂, 1 ♀. Holbert Run 1.61 km (1.0 mi) from CR 2-8/ RT 2 intersection adjacent to CR 2-8, 40.474045, -80.58584; 23 August 2005 – (WLU 05082303), 1 I♂, 1 II♂, 1 ♀. Kings Creek at RT 2 crossing, 40.435715 N / 80.592514 W; 17 October 2005 – (WLU 05101701); 3 I♂, 4 ♀. Tomlinson Run backwater at RT 2 crossing, 40.54026, -80.628075; 8, March 2005 – (WLU 06030801), 9 I♂; 30 March 2005 – (WLU 06033001), 1 I♂. MARSHALL COUNTY: Big Grave Creek at Ohio River confluence in Moundsville, 39.9046, -80.75731; 20 July 2005 – (WLU 05072003 1 ♀; 4 September 2005 – (WLU 05090401), 2 I♂, 1 II♂. Fish Creek at RT 2 crossing, 39.808643, -80.81616; 30 October 2005 – (WLU 05103002), 7 I♂, 2 ♀; 30 April 2006 – (WLU 06043001), 8 O♀. Little Grave Creek at RT 2 crossing in Moundsville, 39.920944, -80.748566; 28 July 2007 – (WLU 05072807), 1 I♂, 1 II♂, 4 ♀. Nameless tributary at RT 2 crossing adjacent to Columbia Chemical operations, 39.85933, -80.79305; 28 July 2007 – (WLU 05072809), 2 I♂. OHIO COUNTY: Short Creek at RT 2 crossing, 40.18312, -80.676865; 4 September 2005 – (WLU 05090404), 2 I♂, 2 ♀. PLEASANTS COUNTY: Ben’s Run at RT 2 crossing, 39.46337, -81.08457; 28 July 2005 – (WLU 05072802), 1 I♂, 2♀. WETZEL COUNTY: Fishing Creek at RT 2 crossing, 39.63576 N/ -80.85848; 20 July 2005 – (WLU 05072001), 2 II♂, 1 ♀. Proctor Creek at RT 2 crossing, 39.70037 N/ -80.81791 W; 20 July 2005 – (WLU 05072001), 2 II♂, 3 ♀.

Orconectes obscurus occurs in north-west New York south through western Pennsylvania and north-central West Virginia, east to Maryland’s portion of the Youghiogheny River system and west to the Flushing Escarpment of Ohio (Hobbs 1989). Ontario populations are considered introduced (Taylor et al. 2007). Orconectes obscurus distribution in western West Virginia appeared to be limited to the Upper Ohio North and Upper Ohio South drainages (Jezerinac et al. 1995). Jezerinac et al. (1995) reported the southern extent of Orconectes obscurus range adjacent to the Ohio River as Proctor Creek at the Marshall/Wetzel counties line, and documented Orconectes sanbornii replacing Orconectes obscurus inFishing Creek, Wetzel County. Jezerinac et al. (1995) also documented Orconectes sanbornii as the dominant orconectid for the Middle Ohio North, Middle Ohio South, and Lower Ohio basins.

Orconectes obscurus has undergone a southern range expansion since Jezerinac’s surveys in the 1980’s (Figure 19). The southern extent of its range currently is Ben’s Run, Tyler County. Orconectes sanbornii’s northern limit currently is Middle Island Creek, due north of Saint Mary’s, Pleasant County. Orconectes obscurus and Orconectes sanbornii divide the Middle Ohio North basin, with Orconectes obscurus inhabiting northern portions of the basin and Orconectes sanbornii inhabiting southern portions (Figure 19).

Figure 19.

Orconectes obscurus and Orconectes sanbornii distribution along the West Virginia portion of the Ohio River floodplain

The southward expansion of the range of Orconectes obscurus could be natural or an anthropogenic event. Orconectes are used as bait because of their ease of capture and high densities (Distefano et al. 2009b), so bait bucket release may explain the southward range expansion. Orconectes obscurus has a history as an invasive, with such populations present in New York and Ontario, Canada (Crocker and Barr 1968; Taylor et al. 1996). Many of the streams containing Orconectes obscurus populations in the southern region of the Middle Ohio North basin are second or third order streams that do not harbor large game fish populations.

Two alternative hypotheses explaining this expansion may include previous misidentification and natural expansion. Orconectes obscurus may have always been present historically where the species was collected in this survey, and misidentified by previous investigators. It is also possible that the species has expanded under natural conditions southward since the 1980’s, specifically invading the Hannibal Pool of the Ohio River and replacing Orconectes sanbornii in the mainstem. After displacement of Orconectes sanbornii in the Ohio River mainstem, additional streams could be colonized via stream confluences.

The largest individual was a 39.0 mm TCL form I male collected in Tomlinson Run backwater in Hancock County. The largest female was collected from the confluence of Little Grave Creek and the Ohio River in Marshall County and possessed a 37.4 mm TCL . Mean TCL for the species was 29.2 mm (n = 82, SE = 8.77). Sexual dimorphism is displayed in this species, with form I and form II male chelae significantly larger (t(345) = 6.8201, p = 0.0001) than female chelae. Morphometric data for Orconectes obscurus is presented in Table 8.

Orconectes obscurus (Figure 20) occupy stream habitats throughout the central and northern regions of the floodplain. Habitats include first through fifth ordered streams and Ohio River backwaters. Healthy populations of Orconectes obscurus occur in all 3rd through 5th ordered streams from Ben’s Run, Tyler County, north to Tomlinson Run, Hancock County. Orconectes obscurus were frequently collected from streams within two specific macrohabitats. Slab boulders and leaf packs were utilized by all demographics; form I males were associated primarily with slab boulders. Leaf packs in pool thalwegs were utilized with increased frequency by Orconectes obscurus juveniles. Based on captive observations, leaf packs offer both structural protection and periphyton for foraging (Z. Loughman personal obs.).

Figure 20.

Orconectes obscurus, Upper Ohio North basin, Ohio County, West Virginia - WLU 05072807

Orconectes obscurus is also a tertiary burrower, creating minimal burrows under substrate items. Small gravel and cobble piles usually were present along margins of slab boulders harboring Orconectes obscurus. One significant behavioral difference between the genera Orconectes and Cambarus along the floodplain is the difference in expressed territoriality. Orconectes obscurus and other orconectids displayed limited territorality. In one instance in Cross Creek, Brooke County, 11 individuals were collected from a single slab boulder.

Orconectes obscurus were collected from two ephemeral streams. This habitat has not previously been reported for the species, and is rarely reported forany Orconectes species(Distefano et al. 2009a ). In Brooke County, Orconectes obscurus were observed in a first order stream tributary to the Ohio River mainstem, foraging on large mats of Cladophora spp. In another headwater stream in Brooke County, they were collected 1.5 km from the river mainstem and had traversed three 1.0 m waterfalls and their associated plunge pools. It is likely that these crayfish inhabit the mainstem of the river and had migrated into the stream, returning to the river during periods of drawdown.

Jezerinac et al. (1995) described Orconectes obscurus’s and Orconectes sanbornii’s life cycle in West Virginia. Form I males are present from fall into winter and mate in the early spring. After spring mating, males molt into second form in late June and proceed throughout most of the summer in this condition (Table 9). Life history data collected during this study validate Jezerinac et al.’s (1995) findings. Beginning in late April and continuing through mid May, females extruded eggs and carried instars. Ovigerous females were collected on 8, 9, and 12 May 2007. Pleopodal egg counts averaged 113 (n = 8 females, SE = 18.2) with a mean egg diameter of 1.7 mm. There was no correlation between pleopodal egg number and TCL (r2 = 0.88, n = 8). Beginning in late June of both 2005 and 2006, young of the year were frequently captured, indicating their release from female’s pleopods. Males in late July and early August underwent a late summer molt into first form condition (Table 9). After this molt, mating effort increased through late summer and fall until winter hibernation. In addition to the late summer molt, males molted in mass during May at the same time that females became ovigerous. This life history mirrors that of Ohio populations as well (Fielder 1972). Crayfish associates collected with Orconectes obscurus include Cambarus carinirostris, Cambarus bartonii cavatus, Cambarus robustus, and Cambarus thomai.

Orconectes obscurus populations are stable and expanding southward along the floodplain. Determining if this expansion is a natural or anthropogenic event is important for conservation of any crayfish species that Orconectes obscurus may ultimately extirpate.

Rostrum with slghtly converging margins, not thickened, with marginal spines or tubercles; median carina absent. Cephalothorax ovoid, slightly, dorsoventrally compressed, without setae. Areola 3.4–9.3 times longer than wide, comprising 31–37% of TCL, with 2–3 rows of punctations across narrowest region; cervical groove interrupted just above cervical spine; lacking hepatic spines; suborbital angle obsolete. Antennal scale about 1.5 times as long as wide; basiopodite spine of antenna well developed; ischiopodite of antenna without spine. Chelae smooth, broad and robust, length 85% of TCL; mesial surface of palm with two well developed rows of tubercles; mesialmost row consisting of 7–11 tubercles; dorsolateral row with 7–11; lateral margin of propodus smooth, dorsal surfaces of both dactyl and fixed finger of propodus with weak dorsolateral ridges; some elongate setae at base of fixed finger. First form male gonopods short, comprising 30% of TCL, with two terminal elements about subequal length; corneous central projection comprising 16% of pleopod length, tapering distally to point; mesial process non-corneous, spatulate, partially surrounding central projection; cephalic base of central projection sloping, without right angle shoulder. Form two male gonopod non-corneous, blunt, shoulder not prominent or absent. Female annulus ventralis deeply embedded in sternum, moveable, wider than long, cephalolateral prominences flattened; fossa and sulcus shallow; sinus straight.

Carapace, abdomen and dorsal surface of chelae brown; rostral margins, caudal edge of carapace, and central surface of terga dark brown; tips of chelae and tubercles at dactyl base orange; tubercles on mesial and lateral margins of dactyl, mesial margin of palm, and mesial margin of fixed finger of propodus, and two spines or tubercles on anterodorsal surface of carpus, yellow; reddish stripe on lateral margin of chelae; ventral margins beige.

Orconectes sanbornii were collected from four counties at seven locations in the current study, as listed below.

JACKSON COUNTY: Little Mill Creek at crossing of RT 33 N 9.43 air km (5.86 mi) N of Ravenswood, 38.86171, -81.85407; 20 July 2006 – (WLU 06072001), 1 II♂, 2 ♀. Little Sandy Creek at intersection of RT 68/CR 8, 38.991497, -81.761765; 21 July 2006 – (WLU 06072103), 1 I♂, 1 II♂, 11 ♀, 4 Juv. MASON COUNTY: Sliding Creek at intersection of CR 4/RT 33, 38.999382, -81.987686; 20 July 2006 – (WLU 06072002), 2 I♂, 1 ♀. PLEASANTS COUNTY: Middle Island Creek at RT 2 crossing, 39.40328, -81.197624; 21 July 2006 – (WLU 06072104), 1 II♂, 2 ♀. WOOD COUNTY: Big Run at CR 21-1 crossing, 39.364048, -81.45656; 21 July 2006 – (WLU 06072106), 3 II♂, 5 ♀, 1 Juv. Lee Creek at CR 11 crossing, 39.153275, -81.73507; 21 July 2006 – (WLU 06072102), 1 II♂, 2 ♀. Nameless tributary crossing 3.54 km (2.2 mi) S of Parkersburg, 39.05142, -81.742836; 21 July 2006 – (WLU 05072105), 1 II♂, 1 ♀.

Orconectes sanbornii occurs throughout the Middle Ohio river drainage in Ohio, West Virginia and Kentucky (Taylor and Schuster 2004). Sites harboring Orconectes sanbornii are shown in Figure 19. The most northern historic populations of the species on the floodplain occurred in Fishing Creek, Wetzel County were recently replaced by southward expanding Orconectes obscurus populations. Orconectes sanbornii is absent from lower reaches of Fishing Creek associated with the confluence of the Ohio River, and still is present in mid- and headwater sections of Fishing Creek (Loughman, unpublished data). Currently, Orconectes sanbornii inhabits the Middle Ohio North, Middle Ohio South, and Lower Ohio basins (Figure 19). Within these basins, Orconectes sanbornii is the only native orconectid.

The largest individual was a female with a 35.5 mm TCL from West Creek, Jackson County. The largest male was a form I with a TCL of 34.3 from West Creek. The mean TCL for Orconectes sanbornii was 24.15 mm (n = 35, SE = 8.91). Morphometric data for Orconectes sanbornii is presented in Table 9.

Orconectes sanbornii (Figure 21) habitat requirements were similar to those of Orconectes obscurus. Orconectes sanbornii is typical of tertiary burrowing crayfish, and inhabited small-to large-sized streams. Slab boulders, leaf packs, and depositional environments were all habitats used by the species. Based on this study, the life cycle of Orconectes sanbornii mirrors that of Orconectes obscurus (Table 9).

Figure 21.

Orconectes sanbornii, Middle Ohio South, Jackson County, West Virginia – WLU 06072103

Orconectes sanbornii demonstrated the same gregarious behavior observed in Orconectes obscurus. Behavioral differences observed between Orconectes obscurus and Orconectes sanbornii specifically differed in the use of stream cover.In West Creek, Jackson County, Orconectes sanbornii were observed exposed in the stream channel. Orconectes sanbornii used interstitial spaces between boulder margins, and the majority of individuals were collected from exposed areas. Orconectes sanbornii were exposed mid-channel resting on the stream bottom with their antennae held posteriorly over their cephalothorax, and would not seek cover until prodded. Orconectes were noted for using cover less than cambarids in this study, but the extreme level of behavior observed in Orconectes sanbornii warrants special mention. Crayfish associates collected with Orconectes sanbornii include Cambarus bartonii cavatus and Cambarus thomai.

The ramifications of Orconectes obscurus expansion southward into historic ranges of Orconectes sanbornii remains to be seen. This interaction needs to be monitored to determine the true relationship between these sibling species.