Procambarus (Ortmannicus) luxus , Johnson, Daniel P., 2011
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|Procambarus (Ortmannicus) luxus|
Procambarus (Ortmannicus) luxus , new species
Corpus Christi Crayfish
Diagnosis. Body pigmented, eyes well developed. Rostrum with or without minute marginal tubercle but usually lacking median carina. Carapace with cervical tubercle slightly larger than neighboring tubercles. Areola 12.5 to 21.2 (mean 17.7 ± 2.9) times as long as wide, constituting 32.2 to 36.7 (mean 34.7 ± 1.6) percent carapace length and 41.5 to 46.2 (mean 44.8 ± 1.6) percent postorbital length. Suborbital angle obtuse and weak; postorbital ridge with minute cephalic tubercle; hepatic area tuberculate; brancheostegal spine acute and small. Antennal scale approximately twice as long as wide, widest at midlength. Ischia of third and fourth pereiopods bearing hooks, hook of third pereiopod overreaching basioischial articulation and lacking opposing tubercle on basis. Coxa of fourth pereiopod with large caudomesial boss, that of fifth smaller and flattened. First pleopods reaching coxae of third pereiopods when abdomen flexed, asymmetrical, proximally separated by gap, and tapering distally; cephalomesial margin lacking prominent hump. Terminal elements all corneous and consisting of: (1) slender acute, tapering mesial process directed caudodistally and slightly laterally with apex lying mesial to central projection; (2) cephalic process somewhat obscuring central projection in cephalic aspect, inclined mesially, tapering from broad base, apex acute, directed caudally and slightly laterally, apex lying mesial to central projection; (3) acute, tapering caudal process inclined mesially, apex lying lateral to central projection and directed caudodistally; (4) central projection largest of elements, inclined mesially, apex directed caudally and slightly laterally. Setiferous caudal knob situated at lateral aspect of cephalic process base. Annulus ventralis twice as broad as long, prominent caudomedian tonguelike prominence directed ventrally, sinus originating slightly dextral to median, extending under slightly raised cephalodextral wall, curving sinistrally across midline and then dextrally before terminating on aforementioned tonguelike prominence; sternum immediately cephalic to annulus with modest tuberculation and slightly or not overhanging annulus. Unadorned postannular sclerite campanulate to triangular and more that half as broad as annulus. Female with first pleopods.
Holotypic male, form I. Cephalothorax ( Fig. 1View FIGURE 1, 2View FIGURE 2 a, b) 1 ovate in section, slightly depressed. Abdomen narrower than cephalothorax (18.5 and 22.2 mm, respectively). Greatest width of carapace slightly more than height at caudodorsal margin of cervical groove. Areola 20.6 times as long as wide with single row of punctations at narrowest part. Cephalic section of carapace 2.0 times as long as areola, length of latter comprising 33.5 % of entire length of carapace (46.1 % of postorbital carapace length). Surface of carapace punctate dorsally, granulate laterally. Rostrum slightly deflected ventrally with converging slender margins, acute apex of very short acumen nearly reaching distal margin of ultimate segment of antennular peduncle; base of acumen marked by small indentations but lacking marginal tubercles; dorsal surface concave with hint of median carina and with punctations restricted to lateral margins and caudal fourth. Postorbital ridge well developed, grooved laterally and bearing small tubercle at cephalic extremity. Suborbital angle weak and obtuse. Branchiostegal spine small. Cervical tubercle twice the size of neighboring ones on caudolateral flank of cervical groove.
Abdomen slightly shorter than carapace (46.0 and 49.3 mm, respectively). Pleura of third through fifth segments subtruncate with subangular caudoventral extremities. Cephalic section of telson ( Fig. 2View FIGURE 2 i) with two spines in
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caudolateral corner; caudal section with shallow median excavation on caudal margin. Cephalic lobe of epistome elliptical; central area subplanar and minutely punctate; margins raised and slightly irregular cephalically; distinct median longitudinal groove on main body. Ventral surface of proximal podomere of antennular peduncle with spine at midlength. Antenna with small spiniform tubercles on basis and ischium; flagellum reaching slightly beyond caudal margin of telson. Antennal scale ( Fig. 2View FIGURE 2 j) 2.1 times as long as wide, widest at midlength; lamellar area much wider than thickened lateral part.
Third maxilliped extending cephalically to level of ultimate podomere of antennule; ventral surface densely covered with plumose setae.
Right chela (left in Figs. 2View FIGURE 2 c –f) distinctly elongate, subovate in cross section, weakly depressed. Mesial margin with row of 8 tubercles subtended by more squamous ones dorsally and ventrally; tubercles present over all except ventrolateral part of palm and also present on basal parts of both fingers. Dorsal and ventral longitudinal ridges not obvious on either finger. Opposable surface of fixed finger with dorsally situated row of 10 (12 on left) tubercles along proximal third and lower row of 7, one of which much larger than other tubercles on finger; broad band of minute denticles situated between rows of tubercles extends entire length to base of corneous tip of finger; except for proximolateral squamous tubercles, finger is covered by scattered weak to moderate punctations. Opposable margin of dactyl with row of 8 (9 on left) tubercles on proximal fourth; broad band of minute denticles present on distal 4 / 5 ths; mesial surface with row of 3 (4 on left) tubercles on proximal fourth followed distally by punctations; dorsal and ventral surfaces weakly punctate.
Carpus of cheliped longer than broad with distinct oblique furrow dorsally, tuberculate mesially, dorsomesially and ventromesially; mesial surface with 2 tubercles larger than others, one near midlength and one distomesially; ventral surface with usual 2 tubercles on distal margin.
Merus with few weak tubercles dorsally, except for two larger ones distally; mesial surface with tubercles on distal fourth, otherwise punctate; lateral surface punctate; ventral surface ( Fig. 2View FIGURE 2 g) with mesial row of 17 (18 on left) tubercles and lateral row of 11 (13 on left). Ischium with ventromesial row of 4 tubercles (6 on left).
Hooks on ischia of third and fourth pereiopods ( Fig. 2View FIGURE 2 h) simple, that on third overreaching basioischial articulation, that on fourth not overreaching articulation and not opposed by tubercle on corresponding basis.
Coxa of fourth pereiopod with prominent subvertically oriented caudomesial boss; that of fifth with smaller one strongly compressed longitudinally. Sternum between third through fifth pereiopods moderately deep and bearing fringe of ventromesially directed plumose setae on ventrolateral margins.
First pleopods ( Figs. 3View FIGURE 3 a –h, 4 a) as described in diagnosis.
Uropod ( Fig. 2View FIGURE 2 i) with both lobes of basal podomere bearing single acute spines; mesial ramus with well developed median carina terminating in distinctly premarginal spine and weak distolateral spine.
Allotypic female. Differing from holotype, except in secondary sexual characters, as follows: Areola 18.1 times as long as wide with no punctations at narrowest part. Cephalic section of carapace 1.8 times as long as areola, length of latter comprising 35.3 % of entire length of carapace (44.9 % of postorbital carapace length). Acumen with apex reaching distal margin of ultimate segment of antennular peduncle, base with weak marginal tubercles. Rostrum without hint of median carina. Abdomen slightly longer than carapace (44.0 and 41.1 mm, respectively).
Main body of epistome with less distinct longitudinal groove, cephalic end approaching form of fovea. Both flagella broken, missing distal extremities. Antennal scale 1.9 times as long as wide. Right chela less distinctly elongate and somewhat more depressed; mesial margin of palm with row of 6 tubercles; opposable surface of fixed finger with dorsally situated row of 7 (5 on left) tubercles along proximal third (one larger than rest) and single large tubercle corresponding to lower row in holotype; opposable margin of dactyl with row of 11 (12 on left) tubercles on proximal half. Merus with few weak tubercles distomesially; ventral surface with mesial row of 11 (12 on left) tubercles and lateral row of 6 (11 on left). Ischium with ventromesial row of 4 tubercles (5 on left). Annulus ventralis and adjacent sternal region ( Figs. 5View FIGURE 5 a, b) as described in "Diagnosis".
Morphotypic male, form II. Differing from holotype in following respects: Cephalothorax slightly raised. Areola 14.5 times as long as wide. Cephalic section of carapace 2.1 times as long as areola, length of latter 32.2 % of entire length of carapace (41.5 % of postorbital carapace length). Rostrum with more distinct indentations at base of acumen, dorsal surface without hint of median carina and with punctations restricted to lateral margins. Cervical spine present. Abdomen slightly longer than carapace (37.8 and 36.0 mm, respectively). Cephalic lobe of epistome apunctate. Flagellum of antenna nearly reaching caudal margin of telson. Antennal scale 2.4 times as long as wide. Right chela mesial margin with row of 6 tubercles; opposable surface of fixed finger with dorsally situated row of 6 tubercles and lower row represented by single large tubercle at midlength; opposable margin of dactyl with row of 10 (11 on left) tubercles on proximal third. Ventral surface of merus with mesial row of 13 (15 on left) tubercles and lateral row of 11 (7 on left). Ischium with ventromesial row of 4 tubercles. Hooks on ischia of third and fourth pereiopods and bosses on fourth and fifth much reduced. First pleopods ( Figs. 4View FIGURE 4 b, c) with all terminal elements evident, but noncorneous and reduced compared to holotype; cephalic process and central projection directed at about 80 degrees to axis of shaft; subapical setae present; juvenile oblique suture clearly visible on shaft.
County Latitude/Longitude Collection date County Latitude/Longitude Collection date Bee 28.21715 –97.64654 24 Apr 2010 Nueces (cont.) 27.73967 –97.76309 8 Oct 2010 Color notes. Holotype ( Fig. 1View FIGURE 1): Predominant coloration of body brick red with tan pereiopods. Carapace brick red with ventral fifth cream, caudal gastric region brown; dorsolateral weak tubercles of carapace tan to greenish tan; stronger lateral and ventrolateral tubercles white. Cervical groove olive dorsally, white mid laterally, and olivetan ventrally. Branchiocardiac groove tan. Caudal ridge, postorbital ridge and margin of orbit olive-tan. Rostral margin tan. Abdomen with broad, charcoal, dorsal stripe terminating on cephalic margin of fifth tergum, slightly broken by tan caudal margins of terga; another narrower charcoal stripe at junction of terga and pleura on 2 nd through 5 th segments; small white spots at cephalolateral regions of terga 1 through 5. Telson and uropods with scattered dark spots and spines white. Oblique white stripes near cephalic margin of telson. Flagella of antenna and antennule gray-tan and white, respectively. Cheliped tan dorsally and light tan ventrally; spines white with occasional corneous tip; tubercles on dorsal surface of palm charcoal, those of carpus and merus olive; tubercles on ventral surface of palm and carpus white; articular condyles brick red.
Type locality. Canal and roadside ditch near Interstate 37 and County Road 17, San Patricio County, Texas (28.09435, - 97.80987). Site is bordered by a large highway and cropland. At time of collection, the ditch contained water one foot deep and 12 feet wide, but appeared temporary as the bottom contained non-hydrophilic vegetation. The canal was unvegetated and unflowing with water to one meter deep.
Disposition of types. The holotype, allotype, and morphotype (Nos. 1154636, 1154637 and 1154638) 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 the same location.
Size. The largest specimen examined is a female with a carapace length of 64.0 mm (postorbital carapace length of 49.9 mm). The largest male is second form and has a carapace length of 60.0 mm (postorbital carapace length of 45.7 mm). The smallest first form male has a carapace length of 35.2 mm (postorbital carapace length of 26.6 mm). Sizes of ovigerous females and females carrying young are not available as none have been found.
Range and specimens examined. Two hundred and eight specimens have been examined, including 24 3 I, 8 3 II, 38 Ƥ, 85 j 3 and 53 jƤ. All were collected by the author at 53 sites ( Table 2) in the following seven counties (number of sites in parentheses): Bee (4), Brooks (3), Jim Wells (15), Kleberg (4), Nueces (16), Refugio (3) and San Patricio (8).
Variations. The palm width of the cheliped of most first form males is proportionately wider than in the holotype, indicating the holotype's chelipeds could possibly have been regenerated from a young age; although its tuberculation is not significantly different from that of other first form males. The number of tubercles on the opposable margin of the fixed finger varies from 4 to 12; while the number for the opposable margin of dactyl varies from 8 to 12. The gap between the proximal extremities of the first pleopods of first form males is always present, but varies in width from 1.5 % to 7.6 % of the pleopod length. A large majority of specimens show no hint of a rostral median carina; however, one paratype has a pronounced one and the holotype has a hint of one. In small juveniles with carapace lengths from 7 to 17 mm, the marginal spine at the base of the acumen is well developed; the spine is occasional present in medium sized individuals; in adults the spine is missing or reduced to a barely discernible tubercle, a marginal indentation is always present however. Cervical and branchiostegal spines are comparatively more pronounced in younger specimens. In small females, the caudomedian tongue-like prominence of annulus ventralis is less pronounced than in adults.
Relationships. Procambarus (Ortmannicus) luxus has its closest affinities with P. ( O.) texanus (Hobbs, 1971) . More distant affinities exist with (in order of decreasing affinity) P. ( O.) zonangulus , P. ( O.) nueces , P. ( O.) acutus and P. ( O.) nechesae . P. ( O.) l u x u s may be distinguished from all by the first pleopod's more strongly recurved cephalic process, central projection and caudal process with the tips of the cephalic process and central projection directed 90 degrees to the pleopod's axis (close in P. ( O.) texanus ). The processes of its first pleopod are proportionately shorter than those of all except P. ( O.) texanus . Its strongly corneous, narrower, less laterally deflected mesial process is distinct from all except that of P. ( O.) nueces , which is similar in lateral deflection but is much more robust and only slightly corneous. The caudomedian tongue-like prominence of the annulus ventralis is much more pronounced than in all except P. ( O.) nechesae . The gap between the proximal extremities of the first pleopods is very distinct from all except P. ( O.) nueces which is weakly differentiated by a smaller gap. P. ( O.) l ux u s is further distinguished from P. ( O.) texanus , P. ( O.) zonangulus and P. ( O.) nueces by much more strongly asymmetrical first pleopods; from P. ( O.) acutus and P. ( O.) nueces by a more strongly tapered first pleopod; from P. ( O.) zonangulus by a lack of a distinct caudomesial hump on the first pleopod proximal to the terminal processes; from P. ( O.) texanus by an annulus ventralis that is less strongly overhung by a less tuberculate sternum; from P. ( O.) acutus , P. ( O.) nueces and P. ( O.) zonangulus by the lack of a distinctly raised dextral side of the annulus ventralis; and from P. ( O.) nechesae by the much narrower caudal process of the first pleopod.
Further supporting Procambarus ( O.) luxus as a valid species is its geographic isolation from other members of the subgenus. Its range is separated from that of the geographically closest "member", the zonangulus - texanus complex (defined in "Introduction"), by 80 km and from that of P. ( O.) nueces by 110 km, while the ranges of P. ( O.) acutus and P. ( O.) nechesae are far removed.
Ecological notes. Specimens were collected in roadside ditches, culvert pools, streams and ponds bordering cropland, hay fields, cattle ranches and urban areas. At one site, two females were collected from separate burrows on a stream bank; both had simple, subvertical shafts to 80 cm depth and were plugged. The remaining specimens were collected from open water with a dip net. One site had brackish water with distinctly salty taste and an abundance of ghost and hermit crabs, while all other sites contained fresh water.
Etymology. Luxus (L.) = dislocated, alluding to the prominent gap separating the proximal extremities of the first pleopods of first form males.
Crayfish associates. Found with P. ( O.) l u x u s were the following crayfishes, in order of decreasing frequency; Cambarellus (Pandicambarus) ninae , P. (Girardiella) cf regiomontanus, Fallicambarus (Creaserinus) fodiens and P. (Scapulicambarus) clarkii .
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No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.