Fallicambarus (F.) kountzeae, Johnson, Daniel P., 2008

Johnson, Daniel P., 2008, Descriptions of two new crayfishes of the genus Fallicambarus from southeast Texas with notes on the distribution of F. (F.) macneesei, Zootaxa 1717, pp. 1-23 : 13-22

Fallicambarus (F.) kountzeae new species

Big Thicket Burrowing Crayfish Figs 11–17

Diagnosis.—Rostrum devoid of marginal spines. Areola obliterated. Ischia of third and fourth pereiopods of form I males with hooks. Coxa of fourth pereiopod with massive boss. First pleopod with proximomesial spur, and terminating in three elements (central projection, mesial process and cephalic process). Central projection scythelike; disposed proximocaudally, never overlapping that of corresponding pleopod; lacking a subterminal notch; and strongly curved caudally with distal end directed approx 180 degrees to main shaft of appendage. Mesial ramus of uropod with distolateral and distomedian spines; distomedian spine never projecting beyond margin of ramus. Cheliped without sufflamen.

Holotypic male, form I.—Body suboval ( Fig 11 ). Abdomen narrower than thorax (9.1mm and 12.1mm respectively). Greatest width of carapace (also 12.1mm) distinctly posterior to caudodorsal extremity of cervical groove. Greatest height of carapace 12.9mm. Areola ( Fig 12 a) obliterated and comprising 35 percent of the entire length of the carapace and 41 percent of the postorbital carapace length. Rostrum ( Fig 11 d) with converging margins. Dorsal surface concave with submarginal row of setiferous punctions and many scattered punctations in between. Postorbital ridges well defined; posterior swelling slight. Acumen triangular with upturned apex and extending to midlength of penultimate podomere of antennular peduncle. Suborbital angle ( Fig 12 b) obsolete. Branchiostegal and cervical spines absent. Carapace punctate dorsally and dorsolaterally, granulate ventrolaterally.

Abdomen ( Fig 13 ) slightly shorter than carapace (26.7mm and 27.4mm); pleura very short and broadly rounded ventrally; only that of sixth segment with angular caudoventral margin. Cephalic section of telson ( Figs 16 e) with pair of well defined spines on caudolateral margin. Entire dorsal surface of telson covered by setiferous punctations. Mesial ramus of uropod with distolateral and distomedian spines; distomedian spine not projecting beyond margin of ramus. Proximal podomere of lateral ramus bearing numerous spines along diarthrosis.

Ventral surface of proximal podomere of antennule with median spine slightly distal to midlength. Antennal peduncle without spines. Flagellum reaching caudal margin of 2nd abdominal segment. Antennal scale ( Fig 11 c) 2.7 times as long as wide, widest distal to midlength.

Right chela ( Fig 14 ) 2.2 times as long as wide. Mesial margin of palm 0.63 times as long as width of chela and bearing row of 9 tubercles subtended dorsalaterally by row of 6 smaller ones. Dorsal surface of palm and basal half of fingers covered with weak tubercles; tubercles on lateral margin of chela ( Fig 14 c) forming subserrate row extending from proximal extremity to midlength of fixed finger. Ventral surface of palm ( Fig 14 d) weakly tuberculate. Ventral surface of fingers punctate. Opposable margin of fixed finger with row of 9 tubercles, fourth from base largest; distal half with single row of minute denticles. Opposable margin of dactyl with proximal concavity and bearing row of 10 tubercles; single row of minute denticles on distal half, interupted by previously mentioned tubercles.

Carpus of cheliped ( Fig 14 a) bearing poorly delimited, submedian, longitudinal furrow dorsally, flanked mesially by punctations and tubercles and laterally by punctations; mesial surface tuberculate; dorsomesial angle bearing row of 7 tubercles, mesial margin with three spurlike tubercles; ventral surface devoid of tubercles except for one on distal margin. Merus weakly serrate dorsally, distalmost serration in form of spiniform tubercle; mesial and lateral surfaces weakly punctate; ventral surface ( Fig 15 a) with mesial row of 15 tubercles and lateral one of 11; few additional tubercles adjacent to rows. Mesioventral margin of basioischial podomere with row of 4 tubercles distal to fracture suture; compound podomere otherwise weakly punctate. Cheliped without sufflamen ( Fig 15 b). Second pereiopod with rows of plumose setae on mesial and lateral margins of chela, carpus, and merus.

Ischia of third and fourth pereiopods ( Figs 15 c) with well developed hooks; neither overreaching basioischial articulation. Coxa of fourth pereiopod with massive boss having almost straight caudoventral margin.

First pleopods ( Figs 16 a–d) reaching coxae of third pereiopods when abdomen flexed, carried deeply in sternum and largely concealed by setae extending from ventral margin of sternum and from coxae of third and fourth pereiopods. Proximomesial spur well defined. Mesial process non-corneous, tapering and directly at 120 degrees to main axis of appendage; cephalic process short, corneous, and directly 45 degrees to main axis of appendage. Central projection strongly arched, scythelike, corneous, distal end directed 180 degrees to main axis of appendage. Caudal margin with pronounced row of plumose setae along most of length.

Allotypic female.— ( Fig 17 ) Differing from holotype in other than secondary sexual characteristics as follows: Rostrum extending to distal margin of penultimate podomere of antennular peduncle. Opposable margin of fixed finger of chela with row of 7 tubercles. Ventral surface of merus with mesial row of 13 tubercles and lateral one of 9.

Annulus ventralis ( Figs 17 c) 2.3 times broader than long, immovable, not deeply imbedded in sternum. Cephalomedian area with fossa dextral to midline. Sinus originates in fossa dextrally to midline, curves sinistrally crossing midline, then dextrally before terminating just sinistral to midline. Cephalic portion of sinus open; caudal part closed. Postannular sclerite in the form of a half ellipse, about 0.5 width and 0.7 length of annulus.

Color notes.— The species exhibits two color patterns, solid and striped. Both are seen in mature individuals; however, it's uncertain whether they are distinct color phases or merely result from differences in degree of retention of juvenile color pattern.

Striped pattern (Based on holotype, Fig 11 ): Dominant color of carapace and abdomen medium brown. Light brown stripe bordered by dark brown extending from gastric region to cephalic margin of telson. Cephalic portion of stripe widest cephalically, gradually narrowing caudally to cervical groove. Thoracic portion of stripe widest cephalically, then narrowing, widening and again narrowing towards the caudal margin. Abdominal portion of stripe uniformly narrow. Tubercles on dactyl, propodus, carpus, and merus of cheliped dark brown. Hint of green dorsally at juncture of propodus and dactyl, and at distal margins of carpus and merus. Abdomen with numerous environment-related discolorations in form of dark marks.

Solid pattern (Based on allotype, Fig 17 ): Differs from striped pattern simply in the lack of the aforementioned stripe. Body fairly uniform medium brown to tan.

Type locality.—Grassy highway right of way in loblolly pine forest, Hwy. 69, 2.2 km (1.3 mi) north Rt. 1003, Hardin County, Texas (30°26.6’ N 94° 23.1 W).

Disposition of types.—The holotype and allotype ( USNM 1111164 and 1111165, respectively) are deposited in the National Museum of Natural History, Smithsonian Institution. Other paratypes remain temporarily in the author's collection, but will ultimately be deposited in the Texas Cooperative Wildlife Collection at Texas A&M University upon completion of an ongoing study of Texas crayfish.

Range and specimens examined.—Specimens have been collected from ten locations in two Texas counties ( Fig. 9 ) as follows: Hardin County, Hwy. 69, 1.3 mi (2.2 km) north Rt. 1003 (30°26.6’ N 94°23.1’ W), 1 male I, 2 female, 2 June 2007. Hwy. 69, 3.1 mi (5.2 km) south Rt. 1003 (30°23.7’ N 94°20.2’ W), 1 male I, 1 female, 2 June 2007. Rt. 326, 13.9 mi (22.4 km) north Rt. 105 (30°19.9’ N 94°21.0’ W), 1 juv female, 1 juv male, 2 Feb 2007. Rt. 1003, 1.6 mi (2.6 km) northeast Rt. 1293 (30°24.6’ N 94°24.7’ W), 1 female, 1 juv male, 5 May 2007. Rt. 421 @ Hwy. 96 (30°14.6’ N 94°11.8’ W). 1 male I, 1 female, 2 June 2007. Rt. 421 12.2 mi (20.3 km) west Hwy 69, 1 male I (30°11.9’ N 94°22.6’ W), 2 female, 2 June 2007. Rt. 418 6.9 mi (11.5 km) east Hwy 69 (30°23.1’ N 94°13.1’ W), 1 female, 2 June 2007. Tyler County, Rt. 1943 @ Rt. 3290 (30°37.0’ N 94°23.8’ W), 1 female, 1 juv male, 5 juv females, 3 Feb 2007. Hwy. 69, 0.2 mi (0.3 km) north Hardin County line (30°31.9’ N 94°24.1’ W), 2 male I, 2 females, 5 May 2007. Rt. 2827, 4.7 mi (7.8 km) west Hwy. 69 (30°33.5’ N 94°28.1’ W). 1 male I, 1 female, 2 June 2007.

Size.—Measurements of the holotype and allotype are given in table 2. The largest specimen examined was the allotype with a carapace length of 31 mm. The smallest first form male has a carapace length of 27 mm.

Relationships.— Fallicambarus (F.) kountzeae is apparently most closely related to F. (F.) houstonensis and F. (F.) m a c n e e s e i. F. houstonensis differs in having sufflamen on the cheliped (compare Figs 6 b and 15b). F. macneesei differs in having sufflamen on the cheliped and the median spine of the mesial ramus of the uropod projects beyond the margin (compare Figs 4 b and 16e). F. (F.) devastator , its nearest neighbor to the north, appears to be more distantly related. It differs in that the mesial ramus of the uropod is more acute distally and lacks a lateral spine; the chela are more tuberculate ventrally with the ventrolateral margin more angled and the coloration is strikingly different. F. (F.) petilicarpus of Arkansas differs in that the central projection of the gonopod is disposed proximomesially and the length of carpus of the cheliped is distinctly greater than the width of the palm of the chela

Va r ia ti o ns.—In some males, the cephalic process of the gonopod is reduced compared to the holoype. In approximately 50% of females, the annulus ventralis is a mirror image of the allotype annulus.

Table 2. Measurements (mm) of Fallicambarus (F.) kountzeae n. sp.

Ecological notes.—A primary burrower, 100% of adults and subadults collected (body length greater than 2.5 cm) were taken from burrows. Small juveniles are, however, common in open water during the cool season. Burrows of adults usually have multiple entrances and are often plugged. A common configuration of a given burrow segment is as follows: At the entrance the burrow extends vertically about 6 inches (19cm), then horizontally about 1 foot (38 cm), then vertically again to about 1.5 feet (57 cm) where a chamber containing the occupant(s) can be found. Other burrows were found that spiralled to depth. Most of the burrows were in areas of loose loam and are among the most easily excavated crayfish burrows. In May and June, 100% of males found were form I and the majority of those were found sharing burrows with females. Colonies are typically dense and a prominent part of the landscape. The species is apparently a nuisance in the towns of Kountze, Silsbee, and Lumberton.

Etymology.—The name is derived from the town of Kountze which is located near the center of the range of the species.

Figures

FIGURE 4. Fallicambarus (F.) houstonensis n. sp. (a) Mesial ramus of uropod (c) rostrum and (d) antennal scale of holotype. (b) Mesial ramus of F. (F.) macneesei for comparison to (a). (e) Annulus ventralis of allotype.

FIGURE 9. Texas collection locations of the subgenus Fallicambarus, including houstonensis (red triangles), kountzeae (green circles), macneesei (yellow plus signs) and devastator (purple squares).

FIGURE 11. Fallicambarus (F.) kountzeae n. sp. (a) Lateral view, (b) dorsal view, and (d) rostrum of holotype. (c) Antennal scale of paratype.

FIGURE 12. F. (F.) kountzeae n. sp. holotype. Dorsal (a) and lateral (b) views of cephalothorax.

FIGURE 13. F. (F.) kountzeae n. sp. holotype. Dorsal (a) and lateral (b) views of abdomen.

FIGURE 14. F. (F.) kountzeae n. sp. holotype. Views of Chela.

FIGURE 15. F. (F.) kountzeae holotype n. sp. (a) Ventral view of merus, (b) basal podomeres of cheliped showing lack of sufflamen and (c) basal podomeres of pereiopods.

FIGURE 16. F. (F.) kountzeae holotype n. sp. (a) Ventral view of gonopods; and (b) mesial, (c) caudal and (d) lateral views of left gonopod; (e) uropod

FIGURE 17. Fallicambarus (F.) kountzeae n. sp. allotype. (a) Lateral and (b) dorsal views. (c) Annulus ventralis

FIGURE 6. F. (F.) houstonensis n. sp. holotype. (a) Ventral view of meris, (b) basal podomeres of cheliped showing sufflamen and (c) basal podomeres of left pereiopods.