Fallicambarus (F.) wallsi Johnson, 2011, new species
Creators: name: Johnson, Daniel P.
Publisher: name: Zenodo
Year: 2011
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Cambaridae
Fallicambarus
Fallicambarus wallsi

description: Fallicambarus (F.) wallsi, new species
SABINE BURROWING CRAYFISH Figs 1–6, Tables 1–2
Diagnosis. Body pigmented, eyes well developed. Rostrum of adults devoid of marginal spines. Antennal scale approximately 2.1 times as long as broad. Areola width 2.1 to 5.2 (mean 3.9±1.0) percent of length. Branchiostegal spine present. Cheliped without sufflamen; ventral surface of merus with mesial and lateral rows of tubercles; length of carpus less than width of palm of chela. Chela ungaping, lateral margin subserrate, ventrolateral surface lacking arched row of prominent setiferous punctations; opposable margin of dactyl lacking distinct excision in basal half, mesial margin with tubercles along proximal half; “dactyl/palm mesial margin” length ratio ranges from 1.45 to 1.57, mean 1.51±0.04; proximal margin of palm oriented distomesially mesial to condyle. Mesial surface of palm of chela of second pereiopod lacking conspicuous tufts of plumose setae. First pleopod with proximomesial spur, without cephalic process or with vestigial one; central projection strongly arched, inclined laterally at base, its tip directed proximally and never crossing that of corresponding pleopod when in situ. Hooks on ischia of third and fourth pereiopods. Boss on coxa of fourth pereiopod moderately strong and compressed. Mesial ramus of uropod with distolateral and premarginal distomedian spines and with obtuse distal margin. Telson divided with two spines on anterolateral flank of suture.
Holotypic male, form I. Body (Fig. 1)1 suboval, weakly compressed dorsoventrally. Abdomen distinctly narrower than cephalothorax (11.8 and 14.5 mm, respectively). Greatest width of carapace distinctly posterior to caudodorsal extremity of cervical groove and slightly greater than height (14.5 and 13.6 mm, respectively). Areola width 4.5 percent of length, latter constituting 36.5 percent entire length of carapace and 40.9 percent postorbital carapace length.
Rostrum with convergent, thickened margins contracting anteriorly, forming short, poorly delimited, triangular acumen, apex of which corneous, distinctly upturned, and extending to proximal margin of ultimate podomere of antennular peduncle. Dorsal surface of rostrum concave, especially in cephalic half, with marginal punctations and scattered ones in between. Subrostral ridge weak, but evident in dorsal aspect to base of acumen. Postorbital ridge weak and slightly swollen caudally. Cervical spine or tubercle absent. Branchiostegal spine present. Suborbital angle absent. Carapace punctate dorsally and very weakly and sparsely granulate laterally; extreme anteroventral
1. If viewing in electronic form, figures may be zoomed in for more detail, as the images are high resolution.
branchiostegal region inflated, with row of 7 closely-set tubercles on ventral flank of cervical groove, and 3 nearly indiscernible ones on dorsal flank.
Abdomen slightly shorter than carapace (29.0 and 30.1 mm, respectively); pleura moderately deep and broadly rounded ventrally with fifth and sixth weakly angled on caudoventral margin; pleuron of first abdominal segment clearly overlapped by that of second. Telson distinctly divided, left caudolateral angle of cephalic section with two spines (one on right due to damage). Proximal podomere of uropod with both lobes bearing distal spines, spine on mesial lobe much stronger than that of lateral lobe. Mesial ramus with distolateral and premarginal distomedian spines.
Cephalomedian lobe of epistome (Fig. 2 g) broadly triangular with elevated margins; central area subplanar with sparse minute punctations; main body of epistome with broad depression, but lacking distinct fovea. Ventral surface of proximal podomere of antennule with spine slightly distal to midlength. Antennal peduncle with spine on lateral surface of basis at proximal base of antennal scale, flagellum reaching first abdominal tergum. Antennal scale (Fig. 2 h) 2.1 times as long as broad with blade distinctly wider than thickened lateral part, widest distal to midlength and distomesial margin broadly rounded. Ventral surface of ischium of third maxilliped with fine, short setal tufts on lateral margin and two irregular bands of long stiff setae on mesial half.
Right chela (Figs 2 a–d) 2.3 times as long as broad, not strongly depressed; length of dactyl 1.51 times length of palm mesial margin; proximal margin of palm mesial to condyle oriented distomesially; width of palm 1.2 times length of mesial margin, latter bearing row of 7 tubercles subtended dorsolaterally by row of six smaller ones; dorsal surface of palm and basal part of fingers studded with squamous tubercles; those along lateral margin forming subserrate row extending from near proximal extremity to midlength of fixed finger; ventral surface of palm weakly tuberculate; ventral surface of fingers punctate laterally and mesially; tubercle present on distoventral ridge opposite dactyl. Opposable margin of fixed finger with dorsally situated row of five tubercles (4th from base largest) in proximal half and another more ventrally positioned row of two (one on left) in distal third; minute denticles present between tubercles along entire length. Opposable margin of dactyl with row of 6 tubercles in proximal twothirds (basal three larger than others, third from base marking end of prominent excision present in most other congeners); mesial margin of dactyl with tubercles forming subserrate row along proximal three-fifths. Dorsal surface of both fingers with moderately defined longitudinal ridges.
Carpus of cheliped 1.6 times as long as broad and longer than palm mesial margin, but slightly shorter than width of palm. Dorsal surface punctate and with prominent, oblique, longitudinal furrow; dorsomesial angle with row of 5 tubercles (9 on left); mesial surface with longitudinal row of 3 prominent subspiniform tubercles, two subspiniform tubercles on ventrodistal margin and additional scattered smaller ones; ventral and lateral surfaces punctate. Merus (Fig. 2 e) with single dorsal row of 8 tubercles, increasing in size distally; lateral surface punctate on distal third and along proximal, dorsal and ventral margins; mesial surface with few scattered, small punctations distally; ventral surface with mesial row of 11 (13 on left) tubercles; lateral row of 10 (7 on left); and distal marginal row of 4 (3 on left). Basioischial podomere with row of 4 (3 on left) tubercles along ventral margin. Second pereiopod with row of long stiff setae extending along dorsal margin from distal extremity of merus to tip of dactyl and along ventral margin from midlength of merus to tip of fixed finger (that of carpus and merus sparse); mesial surface of carpus and merus lacking tufts of plumose setae.
Ischia of third and fourth pereiopods (Fig. 2 f) with simple hooks, neither of which overreaches basioischial articulation and neither opposed by tubercle on corresponding basis. Coxa of fourth pereiopod with prominent compressed caudomesial boss approximately disposed along longitudinal axis of body, mesial surface with dense setae and lateral surface with sparse setae. Coxa of fifth pereiopod with small, lamellate, laterally disposed boss; ventral membrane nearly without setae.
First pleopods (Figs. 3 a–c) almost reaching coxae of third pereiopod when abdomen flexed and concealed by setae extending from ventral margin of sternum and from coxae of third and fourth pereiopods. Proximomesial spur well developed. Distal half of shaft only slightly bent caudally. Distomesial shaft with setae along proximal half not obscuring two terminal elements: mesial process noncorneous, strongly tapered from broad base, distal two-fifths lamellate, disposed proximocaudally; central projection corneous, tapering, bladelike structure with tip disposed proximally.
Allotypic female. Differing from holotype in other than secondary sexual characteristics as follows: Both caudolateral angles of cephalic section of telson with two spines. Flagellum of antenna reaching midlength of areola. Right chela of similar shape, but proportionately slightly shorter. Mesial margin of palm with row of 5 tubercles subtending main row. Opposable margin of fixed finger with dorsally situated row of 6 tubercles (7 on left) with 3rd from base largest in proximal three-fourths and single more ventrally positioned tubercle at base of distal third. Opposable margin of left dactyl with 7 tubercles. Carpus of cheliped slightly longer than width of palm; dorsomesial angle with row of 6 tubercles (8 on left); mesial surface with one subspiniform tubercle on ventrodistal margin. Merus with dorsal row of 12 tubercles (10 on left); mesial surface with few scattered, small tubercles distally; ventral surface with mesial row of 9 (11 on left) tubercles and lateral row of 8 (7 on left).
Annulus ventralis (Figs. 3 g–h) distinctly raised, firmly fused to sternum cephalically, 1.8 times as broad as long, lateral margins obtusely angled. Cephalosinistral sector excavate. C-shaped sinus originating at midline of caudal margin and terminating in caudomesial margin of excavation, where it forms a small fossa evident in cephaloventral aspect. Postannular sclerite 1.9 times as broad as long, subrectangular, 0.5 times as wide as annulus; ventral extremity excavate in caudal view.
Morphotypic male, form II. Differing from holotype as follows: Areola width 5.2 percent of length. Both caudolateral angles of cephalic section of telson with two spines. Right chela similar in shape, but proportionately slightly shorter. Opposable margin of fixed finger with dorsally situated row of 6 tubercles in proximal threefourths and a single more ventrally positioned tubercle at base of distal third. Opposable margin of left dactyl with row of 7 tubercles (basal four larger than others). Carpus of cheliped slightly longer than width of palm, dorsomesial angle with row of 8 tubercles. Ventral surface of merus with mesial row of 13 (11 on left) tubercles, lateral row of 7 (8 on left), and distal marginal row of 2. Basioischial podomere with row of 3 (2 on left) tubercles along ventral margin. Hooks on ischia of third and fourth pereiopods and bosses on coxae of fourth and fifth pereiopods evident, but reduced compared to holotype.
First pleopod (Figs. 3 d–e) reaching coxa of third pereiopod when abdomen flexed, lacking proximomesial spur; both processes noncorneous; central projection much more robust, less distinctly separated from mesial process and less recurved (tip directed proximocaudally) compared to holotype.
Color notes. Color patterns in F. (F.) w a l l s i, F. (F.) macneesei (Black, 1967), F. (F.) kountzeae and F. (F.) houstonensis are apparently indistinguishable and all exhibit the same polymorphism with striped and unstriped phases. Of 41 specimens of F. (F.) w a l l s i where color notes were made, 38 (93%) were striped phase, with the remaining 3 solid phase. This ratio is much more skewed than that noted for the other aforementioned species.
Holotype (striped phase, Fig. 1): Basic coloration tan-brown. Cephalic section of carapace anterior to caudal gastric region indistinctly mottled with dark brown and orange-tan, middorsal orange-tan triangle (which anterior section of discontinuous dorsal light stripe) with base at midlength and apex at cephalic margin of caudal gastric region; lateral margins of triangle darkened. Obscure laterally oriented dark band cephalic to triangle connecting dull burgundy spots situated caudal to the caudal extremities of the postorbital ridges. Caudal gastric region dark brown with numerous very fine and distinct tan maculations. Ventral hepatic region burgundy with light flecks; mandibular and antennal regions cream; rostral margins and postorbital ridges olive, latter bordered ventrally by orange-tan; eye stalks burgundy with light distal margins. Antennal scale cream mesially and gray laterally. Flagellum of antenna brown. Mesial flagellum of antennule burgundy basally grading to gray distally; lateral flagellum gray-burgundy. Cervical groove gray ordered by olive. Areola brown grading to orange-brown caudally and cephalically, branchiocardiac grooves light. Light orange-brown band laterally borders branchiocardiac grooves and extends ventrally along caudal margin of cervical groove half way to ventral margin. Aforementioned band in turn bordered laterally by broad dark brown band heavily flecked in the interior with lighter brown. This in turn bordered ventrally by a mid-branchiostegal region of complex mottling of dark gray, cream and burgundy. Ventral third of branchiostegite dull cream and simple. Abdomen with narrow orange middorsal stripe, which expanded on 1st tergum; bordered by broad darker stripe with obscure lighter maculations, which in turn bordered by obscure orange brown stripe which abuts junction of terga and pleura. Pleura dark brown dorsally and caudally, grayish cephaloventrally, with dull burgundy caudally margins and scattered light flecks. Tail fan translucent gray, with olive ridges and orange-brown caudal margins of telson and uropods. Cheliped with merus cream proximally and tan to brown distally with bluish or greenish tubercles; carpus tan with white spines along mesial margin; propodus dull burgundy on mesial half grading to tan on lateral half, tubercles on mesial margin and dorsal surface dull bluegreen to dark gray. Dactyl tan with dull blue-green tubercles on mesial margin. Pereiopods 2-5 cream with small amounts of blue and red at articulations. Ventor cream.
Size. The largest specimen examined is a first form male from San Augustine county, with a carapace length of 32.7 (postorbital carapace length 28.1) mm. The smallest first form male has a carapace length of 29.0 (postorbital carapace length 25.0) mm. The largest female examined is the allotype, with a carapace length of 30.6 (postorbital carapace length 27.0) mm. Sizes of ovigerous females or ones carrying young are unavailable, as none have been found.
Type locality. Roadside ditch and culvert pool, Rt. 1 3.5 km (2.2 miles) south intersection with Rt. 184, Sabine County, Texas (31.32498, -93.97711). Surrounding area is gently rolling young pine woods. Holotype, allotype, morphotype and two paratypes were collected from burrows situated relatively high in relation to ditch and with simple subvertical shafts from 0.75 to 1.0 m depth; upper 0.3 meters soft loam with deeper levels very hard.
Disposition of types. The holotype, allotype and morphotype (Nos. 1154633, 1154634 and 1154635, respectively) are deposited in the National Museum of Natural History, Smithsonian Institution. The paratypes remain in the author's collection, but will ultimately be deposited at this same location.
County Latitude/Longitude Collection date County Latitude/Longitude Collection date Range and specimens examined. One hundred specimens, including 9 3 I, 8 3 II, 6 Ƥ and 77 juveniles were examined. All were collected by the author from 16 sites in Sabine and San Augustine counties, Texas (Fig. 6, Table 2). The type series consists of 2 3 I, 1 3 II and 2 Ƥ. All first form males were raised to that stage in captivity, the holotype and paratype from adult second form and the others from small (ca 18 mm total length) juveniles.
Variations. The cephalolateral margins of the cephalomedian lobe of the epistome may be straight or convex. The length/width ratio of the uropod's mesial ramus varies from 1.39 to 1.57 (mean 1.47 ± 0.07). The number of tubercles in the row on the mesial margin of the chela ranges from 5 to 7. Among first form males, no trace of a cephalic process can be found in 8 of 9 specimens (Figs. 3 b, 4a–d, f–h), but in the remaining specimen a vestigial one is present (Fig. 4 e). The mesial process tip is disposed anywhere between 135 and 180 degrees to the shaft axis; in 78% of specimens, the distal half is serrate with 2–4 acute lobes, which can be most readily viewed in caudodistal aspect (Fig. 3 f). The mesial process caudal extent may be distinctly less than to distinctly greater than the caudal extent of the central projection.
Relationships. The similarity in spination, pereiopod hooks, lack of cheliped sufflamen, indistinguishable color patterns and geographic proximity attest to the close relationship of Fallicambarus (F.) wallsi and its presumed closest relative, F. (F.) kountzeae. F. (F.) w a l l s i may be distinguished from it by the following characters (1 through 3 refer to the cheliped): 1) The proximal margin of the palm (Figs. 5 a–d, 2a, note arrow) is oriented distomesially mesial to the condyle; in F. (F.) kountzeae it is orientated proximomesially (Figs. 5 e–h). 2) The “dactyl/ palm mesial margin” length ratio ranges from 1.45 to 1.57, mean 1.51 ± 0.04 (1.84 to 2.09, mean 1.98 ± 0.09 in F. (F.) kountzeae). This difference is readily apparent in Fig. 5. 3) The dactyl is not distinctly excavated on the proximal half of the opposable margin. 4) The antennal scale (Fig. 2 h) is proportionately wider, with a length/width ratio of approximately 2.1 (2.8 in F. (F.) kountzeae, Fig. 2 i) and with the lamellated mesial part distinctly wider than the thickened lateral part. 5) The areola width/length ratio ranges from 2.1 to 5.2 (mean 3.9 ± 1.0) percent (0.0 to 2.6 [mean 1.6 ± 0.9] percent in F. (F.) kountzeae). 6) The uropod's mesial ramus is proportionately wider, with a length/ width ratio of 1.39 to 1.57 (mean 1.47 ± 0.07) (1.56 to 1.76 [mean 1.7 ± 0.08] in F. (F.) kountzeae). 7) Of the nine first form males available (Figs. 3 b, 4a–h), eight lack any trace of a cephalic process on the first pleopod and one has a vestigial one (Fig. 4 e), whereas a cephalic process is always present in F. (F.) kountzeae (Figs. 4 i–p). 8) The mesial process in mesial view is more strongly tapered on average. 9) Branchiostegal spines are always present, but present only in 15% of adult F. (F.) kountzeae specimens (it is possible this difference is due to greater degree of abrasion in the mostly non-captive raised F. (F.) kountzeae specimens).
Fallicambarus (F.) houstonensis and F. (F.) m a c n e e s e i may be readily distinguished from F. (F.) wallsi by their cheliped's sufflamen and well-defined cephalic processes. F. (F.) macneesei may be further distinguished by the distinctive distomedian spine of the uropod's mesial ramus, which extends beyond the margin.
F. (F.) dissitus (Penn, 1955) and F. (F.) petilicarpus (Hobbs and Robison, 1989) may both be distinguished from F. (F.) wallsi by their proximomesially disposed first pleopod central projections which are frequently crossing when in situ.
Although F. (F.) devastator (Hobbs and Whiteman, 1987) is the geographically closest consubgener of F. (F.) wallsi with a distributional gap of only 25 km between the ranges of the two and with no substantial geographical barrier to gene flow, the former is clearly not closely related to the latter. Among the many differences are very different color pattern and very different morphology of the cheliped, antennal scale, first pleopod, annulus ventralis and tail fan.
Etymology. This crayfish is named in honor of Jerry G. Walls of Louisiana State University and author of “Crawfishes of Louisiana”, for his many contributions to the study of crayfish of the south central United States.
Crayfish associates. Found with Fallicambarus (F.) wallsi were the following crayfishes, in order of decreasing frequency: Procambarus (Girardiella) kensleyi, F. (Creaserinus) fodiens, P. (Ortmannicus) acutus and Faxonella beyeri.
description: Published as part of Johnson, Daniel P., 2011, Fallicambarus (F.) wallsi (Decapoda: Cambaridae), a new burrowing crayfish from eastern Texas, pp. 59-68 in Zootaxa 2939 on pages 59-67, DOI: 10.5281/zenodo.278147