Fallicambarus (Fallicambarus) houstonensis, 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 : 1-11

publication ID	https://doi.org/ 10.5281/zenodo.274154
DOI	https://doi.org/10.5281/zenodo.6229689
persistent identifier	https://treatment.plazi.org/id/03C93454-FFBD-FFEC-FF5E-AC41CA4EF8FA
treatment provided by	Plazi
scientific name	Fallicambarus (Fallicambarus) houstonensis
status	sp. nov.

Treatment

Fallicambarus (Fallicambarus) houstonensis View in CoL new species

Houston Burrowing Crayfish

Figs 1–8 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5. F View FIGURE 6. F View FIGURE 7 View FIGURE 8

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, 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 with sufflamen.

Holotypic male, form I.—Body suboval ( Fig 1 View FIGURE 1 ). Abdomen narrower than cephalothorax (12.0mm and 16.8mm respectively). Greatest width of carapace (also 16.8mm) distinctly posterior to caudodorsal extremity of cervical groove. Greatest height of carapace 15.9mm. Areola ( Fig 2 View FIGURE 2 a) obliterated and comprising 39 percent of the entire length of the carapace and 44 percent of the postorbital carapace length. Rostrum ( Fig 4 View FIGURE 4 c) with converging margins. Dorsal surface concave with submarginal row of setiferous punctions and a few 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 2 View FIGURE 2 b) obsolete. Branchiostegal and cervical spines absent. Carapace punctate dorsally and dorsolaterally, weakly granulate ventrolaterally.

Abdomen ( Fig 3 View FIGURE 3 ) slightly shorter than carapace (33.6mm and 35.0mm); pleura very short and broadly rounded ventrally; only that of sixth segment with angular caudoventral margin. Cephalic section of telson ( Fig 4 View FIGURE 4 a) 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 4 View FIGURE 4 d) 2.2 times as long as wide, widest distal to midlength.

Right chela ( Figs 5 View FIGURE 5. F a–d) 2.3 times as long as wide. Mesial margin of palm 0.76 times as long as width of chela and bearing row of 8 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 forming subserrate row extending from proximal extremity to midlength of fixed finger. Ventral surface of palm weakly tuberculate. Ventral surface of fingers punctate. Opposable margin of fixed finger with row of 8 tubercles, fourth from base largest; distal third with single row of minute denticles. Opposable margin of dactyl with proximal concavity and bearing row of 7 tubercles; single row of minute denticles on distal third, interupted by previously mentioned tubercles.

Carpus of cheliped ( Fig 5 View FIGURE 5. F 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 6 tubercles, mesial margin with two spurlike tubercles; ventral surface ( Fig 5 View FIGURE 5. F d) devoid of tubercles except for one on distal margin. Merus weakly serrate dorsally ( Fig 5 View FIGURE 5. F a), distalmost serration in form a spiniform tubercle; mesial and lateral surfaces weakly punctate; ventral surface ( Fig 6 View FIGURE 6. F a) with mesial row of 15 tubercles and lateral one of 9; few additional tubercles adjacent to rows. Mesioventral margin of basioischial podomere ( Fig 6 View FIGURE 6. F b) with row of 3 tubercles distal to fracture suture; compound podomere otherwise weakly punctate. Cheliped with sufflamen. Second pereiopod with rows of setae on mesial and lateral margins of chela, carpus, and merus.

Ischia of third and fourth pereiopods ( Figs 6 View FIGURE 6. F c) with well developed hooks; that of third overreaching basioischial articulation. Coxa of fourth pereiopod with massive boss having arched caudoventral margin.

First pleopods ( Fig 7 View FIGURE 7 ) 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 ( Fig 7 View FIGURE 7 f). Mesial process non-corneous, tapering and directly at 120 degrees to main axis of appendage; distal extremity split (possibly result of damage; no other specimens examined share this characteristic). 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.—Differing from holotype in other than secondary sexual characteristics as follows: Opposable margin of fixed finger of chela with row of 6 tubercles. Mesial margin of carpus with 6 tubercles, distal one spurlike. Ventral surface of merus with mesial row of 14 tubercles and lateral one of 10.

Annulus ventralis ( Fig 4 View FIGURE 4 e) 1.9 times broader than long, immovable, not deeply imbedded in sternum. Cephalomesian area with fossa sinistral to midline. Sinus originates in fossa sinistrally to midline, curves dextrally crossing midline, then sinistrally, then continues along caudal margin to sternum. Postannuluar sclerite about 0.4 width and 0.7 length of annulus.

Morphotypic male, form II.—differing from holotype in other than secondary sexual characteristics as follows: Acumen extending to cephalic margin of penultimate podomere of antennular peduncle. Mesial margin of palm bearing row of 7 tubercles subtended dorsolaterally by a row of 5 smaller ones. Opposable margin of fixed finger with row of 6 tubercles. Mesial margin of carpus with one spurlike tubercle. Ventral surface of merus with mesial row of 13 tubercles and lateral one of 11.

First pleopod ( Figs 7 View FIGURE 7 c, d) with shaft very similar to holotype; terminal elements non-corneous; cephalic process not evident; mesial process similar to holotype; central projection more robust than in holotype, larger than mesial process.

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.

Solid pattern (Based on holotype, see Fig 1 View FIGURE 1 ): Dominant color of carapace and abdomen medium brown, fading to light brown ventrally. Gastric region with tranverse band of darker brown. Areola including anterior and posterior triangular wedges slightly darker than dominant carapace color. Dorsal half of branchiostegites with scattered dark spots. Abdominal segments with paired dark arcuate bars. Pereiopods medium brown dorsally, cream ventrally. Cheliped with dark tubercles on dorsal and mesial surfaces of dactyl, propodus, carpus and merus, larger ones tipped with cream.

Striped pattern ( Fig 8 View FIGURE 8 ): Differing from solid pattern as follows. Dark bordered light stripe extends middorsally from posterior margin of rostrum to telson. Cephalic portion of stripe widest at midlength, narrowing slightly anteriorly and greatly posteriorly. In thoracic region, margins of stripe within branchiostegites and remain constant distance from branchiocardiac groove, except at posterior end where stripe narrows to width of abdominal stripe. Abdominal portion of stripe constant in width.

Type locality.—Powerline right of way near the junction of Rt. 105 and Truman Road, approximately 3 km (1.8 mi) ESE of Cleveland, Liberty County, Texas (30°20.122’ N 95°03.759’ W).

Disposition of types.—The holotype, allotype, and morphotype ( USNM 1111161, 1111162, and 1111163, 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 six Texas counties. For those counties where only juveniles were collected, a single male was retained to raise to form I in captivity for subsequent preservation as a voucher. As of this writing all individuals have either molted to form I or are large enough to be easily identified as belonging to this species. The following are the locality records ( Fig 9 View FIGURE 9 ): Grimes County, Rt. 1774, 4.9 mi (7.9 km) south Rt. 105 (30°16.9’ N 95°50.0’ W), 1 juv female, 13 Apr 2007. Harris County, Boudreaux Rd @ Boudreaux Estates Rd (30°03.2’ N 95°37.2’ W), 2 juv female, 1 juv male, 10 Feb 2007. Liberty County: Type locality, 2 male I, 1 male II, 8 female, 5 May 2007, 4 male I, 1 male II, 8 female, 21 Oct 2007; 2 male II, 2 female, 29 Oct 2006; Rt. 2090, 0.7 mi (1.1 km) east Montgomery County line (30°12.8’ N 95°06.1’ W), 1 female, 25 Mar 2007. Montgomery County, Hwy 105, 0.1 mi (0.2 km) east Whippoorwill Rd (30°19.8’ N 95°22.2’ W), 1 male I, 2 male II, 6 female, 30 Dec 2006. San Jacinto County: Rt 1725, 0.9 mi (1.5 km) north Liberty County line (30°22.6’ N 95°08.5’ W), 2 male II, 4 female, 1 juv female, 3 juv male, 5 Jan 2007. Rt 1725, 4.1 mi (6.6 km) north Liberty County Line (30°24.8’ N 95°11.5’ W), 2 female, 5 Jan 2007. Waller County, Rt. 1488, 3.8 mi (6.1 km) west of Montgomery county line (30°10.7’ N 95°51.4’ W), 2 juv female, 10 Feb 2007.

Size.—Measurement of the holotype, allotype, and morphotype are given in table 1. The largest specimen examined was the holotype with a carapace length of 35 mm. The smallest first form male has a carapace length of 28 mm.

Relationships.—Given the shape of the form I male first pleopod, Fallicambarus (F.) houstonensis is apparently most closely related to F. (F.) kountzeae and F. (F.) macneesei . It differs from kountzeae in possessing chela that bear sufflamen (compare Figs 6 View FIGURE 6. F b and 15b) and from macneesei in that the median spine of the uropod's mesial ramus never projects beyond it's margin (compare Figs. 4 View FIGURE 4 a and 4b).

Va r ia ti o ns.—No noteworthy variations were seen in the small number of form I males collected. Among females, the annulus ventralis is frequently a mirror image of allotype annulus.

Ecological notes.—The species is clearly a primary burrower. 100% of adult and subadult specimens were collected by excavating burrows. Large numbers of approx 30mm juveniles were collected from temporary pools from Oct through Feb using a dip net. The species is abundant in its range and its burrows can be a significant nuisance to homeowners. Burrows typically have multiple entrances and are frequently plugged ( Fig 10 View FIGURE 10. A ). Pairs of adults in a single burrow were twice found in May.

Etymology.— -ensis (Latin) = a suffix denoting place, locality of country. This species is named after the city of Houston which is located just south of its range.