Procambarus (Girardiella) holifieldi Schuster, Taylor and Adams

Schuster, Guenter A., Taylor, Christopher A. & Adams, Susan B., 2015, Procambarus (Girardiella) holifieldi, a new species of crayfish (Decapoda: Cambaridae) from Alabama with a revision of the Hagenianus Group in the subgenus Girardiella, Zootaxa 4021 (1), pp. 1-32 : 6-11

Procambarus (Girardiella) holifieldi Schuster, Taylor and Adams , new species

( Figure 1–2 , Table 1 )

Diagnosis. The following was generated from 23 adults including 6 form I males, 6 form II males and 11 females; the data are pooled except for sexually related structures: Body pigmented; eyes well developed, average eye diameter for adults 1.6 mm; mean carapace height 13.4 mm, mean carapace width 12.8 mm, mean total carapace length (TCL) 29.6 mm, mean postorbital carapace length (PCL) 25.9 mm; mean width of second abdominal segment (widest segment) 9.9 mm; rostral margins widest at base, mean width 3.9 mm, mean length 4.5 mm, average RW/RL ratio 86.6%, margins gradually converge from base to acumen, smoothly rounding apically to form short acumen, no rostral spines or tubercles, no subrostral spines; branchiostegal sclerites meet mid-dorsally; areola obliterated, linear, average AL/PCL ratio 46.8%, average AL/TCL ratio 41%; no cervical spines; suborbital angle obsolete, margins almost straight or with slight curve; postorbital ridges low, with no anterior spines or distinct tubercles; branchiostegal spine may be absent or present as small tubercle or spine; antennal scale mean length 3.8 mm, mean width 1.4 mm, 2.7 times longer than wide, widest at distal 2/3 of scale, mesial margin with mesial row of dense setation; mesial margin of palm without setiferous mat or beard, mean mesial margin length 7.1 mm, mean palm width 9.1 mm; mesial margin of palm with two rows of tubercles, 5–7 tubercles in first row, 2– 6 in second row, scattered tubercles on mesial third of palm; dactyl of chela mean length 11.7 mm, with large excision at the base, 2–3 tubercles in area of excision, 2–5 tubercles distal to excision area, dactyl terminating distally with large acute tubercle; propodus of chela mean length 19.1 mm, with 3–6 tubercles in excision area, 3– 5 tubercles distal to excision area, distal tubercles almost evenly spaced with small denticles between tubercles, propodus ending distally with large spur; third maxilliped of males in ventral view covered with dense setation on ventral and lateral surfaces of all segments, in females setation less dense on lateral surfaces; margins of sternum between pereiopods of both sexes outlined with dense, long setation, in form I males setation more dense, setae longer; ischia of third pereiopods of form I males with large hook; hook overreaching basioischial joint, hook not opposed by tubercle on basis; coxae of third, fourth and fifth pereiopods without prominences or bosses, fourth may be slightly enlarged; inner ramus of uropods with two conspicuous spines projecting well beyond margin; form I male pleopods symmetrical, distal extremity of first pleopods with the following structures: 1) central projection, prominent, crescent shaped, from caudal view broadly rounded and directed laterally; 2) cephalic process hood-like, in cephalic view extends over the base of the central projection; 3) caudal process, sharply pointed apically, flat blade-like; 4) mesial process not heavily sclerotized, tapering to point apically, in caudal view broadly rounded, directed laterally, extends to or slightly beyond central projection; gonopod elements all present in form II males, greatly reduced in size and distinct in structure, in mesial and lateral views distinct shoulder just proximal to terminal elements; annulus ventralis of females mean width 1.7 mm, moveable, circular in outline with deep trough mesially, and sigmoid deep sinus, anterior third of annulus on both sides of trough with 3–5 large tubercles, tubercles reduced in size and number (0–2) in smaller individuals.

Description of the holotype male, form I. Cephalothorax ( Figure 1 A & K) TCL 29.4 mm and PCL 26.2 mm; subovate, greatly compressed laterally; maximum width slightly less than maximum height (12.4 and 12.9 mm). Abdomen narrower than cephalothorax (9.5 and 12.4 mm). Areola 12.0 mm long, obliterated, linear ( Figure 1 K). Cephalic portion of cephalothorax 1.7 times longer than areola; areola comprising 45.8% of PCL (40.8% of TCL). Surface of carapace punctate dorsally ( Figure 1 K), laterally covered with small rounded tubercles ( Figure 1 A). Rostrum ( Figure 1 K) broadest at base (4.1 mm), 4.1 mm long; sides gradually converging to acumen; margins distinctly thickened; anteriorly rounded without tubercles or spines; acumen small; distinct subrostral ridge without spines. Postorbital ridge ( Figure 1 A) weak with no tubercle or spine anteriorly. Suborbital angle ( Fig. 1 A) obtuse, margins slightly rounded; branchiostegal spine weak consisting of a small tubercle. Cervical spine absent. Margins of sternum of cephalothorax lined with long flexible plumose setae, the first gonopods may be partially obscured as they lay in between the pereiopods.

Abdomen only slight longer than PCL (26.9 and 26.2 mm). Cephalic part of telson with two spines in each caudolateral corner; inner spines moveable ( Figure 1 I). Cephalic lobe of the epistome ( Figure 1 J) somewhat rounded with thickened edges; main body of epistome rectangular in broad outline, zygoma strongly arched. Antennal scale 3.9 mm long and 1.3 mm at widest point; lateral edge with row of erect spine-like setae; mesial margin with row of long, flexible setae ( Figure 1 M).

Third maxilliped well developed; ventral and lateral sides of basal segments covered with long flexible plumose setae; distal segments also with long setae, but not as dense. Right chela ( Figure 1 N) total length 19.9 mm, dactyl length (12.0 mm) about 60 % of total length; dactyl and propodus each with very weak dorsomedian ridges. Palm width greater than palm length (9.6 and 7.7 mm); no plumose beard of setae along palm mesial margin; mesial margin of palm with a row of 6 tubercles, a second row of 6 tubercles and scattered tubercles on dorsal surface of palm. Opposable margin of dactyl with distinctly rounded basal excision; with 3 round tubercles in the excision area, and 2 large rounded tubercles distal to excision. Propodus with 3 large tubercles in excision area and 3 equally distributed tubercles distal to excision area, tubercles almost evenly spaced with small denticles in between and to base of terminal spur. Carpus of cheliped with curved dorsal furrow; one large dorsomesial spine and a number of small rounded tubercles along mesial margin. Hook on ischium of third pereiopod only. Coxae of third, fourth or fifth without prominences or bosses, but coxa of fourth somewhat enlarged caudomesially.

First Form pleopods symmetrical at base with long proximomedian lobe ( Figure 1 H); terminal elements as described in “Diagnosis” ( Figure 1 B, C, D, E and H).

Description of allotype female. Differs from male holotype in the following: Cephalothorax TCL 35.0 mm and PCL 31.5 mm; maximum width slightly less than maximum height (16.1 and 15.5 mm). Abdomen narrower than cephalothorax (12.1 and 16.1 mm). Areola 14.2 mm long, obliterated, linear. Branchiostegal spine small but distinct. Cephalic portion of cephalothorax 1.7 times longer than areola; areola comprising 45.1% of PCL (40.6% of TCL). Rostrum widest at base (5.1 mm), 5.9 mm long. Margins of sternum of cephalothorax lined with long flexible plumose setae, not as dense as in holotype. Abdomen subequal to TCL. Antennal scale 4.1 mm long, 1.5 mm at widest point. Ventral segments of third maxilliped covered with long flexible plumose setae, lateral margins with row of long setae but not as dense or as long as in holotype. Right chela total length 21.8 mm, dactyl length (13.4 mm) 61.5% of total length; palm width greater than palm length (10.4 and 8.4 mm). Opposable margin of dactyl with distinctly rounded excision at base, with 2 round tubercles in excision area and three tubercles distal to excision with denticles in between to terminal spur. Opposable margin of propodus with 3 large tubercles within excision area and 5 almost equally spaced distal to excision, with small denticles in between to terminal spur. No hook on ischium of third pereiopod. Annulus ventralis ( Figure 1 L) as described in “Diagnosis.”

Description of the morphotype male, form II. Differs from male holotype in the following: Cephalothorax TCL 28.2 mm and PCL 24.7 mm; maximum width slightly less than maximum height (12.3 and 12.7 mm). Abdomen narrower than cephalothorax (9.2 and 12.3 mm). Areola 11.7 mm long, obliterated, linear. Branchiostegal spine small but distinct. Cephalic portion of cephalothorax 1.4 times longer than areola; areola comprising 47.4 % of PCL (41.5 percent of TCL). Rostrum widest at base (3.62 mm), 4.35 mm long. Margins of sternum of cephalothorax lined with long flexible plumose setae, not as dense as in holotype. Abdomen somewhat shorter in length than TCL (23.8 and 28.2 mm). Antennal scale 3.9 mm long, 1.4 mm at widest point. Right chela total length 19.0 mm, dactyl length (12.1 mm) about 63.7 % of total length; palm width greater than palm length (8.9 and 6.6 mm); Opposable margin of dactyl with distinctly rounded excision at base; with 3 round tubercles in excision area and 2 tubercles distal to excision with denticles in between to terminal spur. Opposable margin of propodus with 3 large tubercles within excision area and 4 almost equally spaced distal to excision, with small denticles in between to terminal spur. Hook on ischium of third pereiopod, much smaller than on holotype. Gonopod length 8.8 mm, all four terminal elements present and identifiable, description of placement similar to holotype terminal elements, but greatly reduced from holotype ( Figure 1 F & G).

Color. ( Figures 2 and 3 ). Dorsum of the carapace is deep royal blue, all appendages from dorsal view usually a lighter blue. Punctations on body and legs stand out with lighter blue to straw color. Basal segments of cheliped light blue, chelae blue basally turning to purple distally, fingers lighter blue to tan with larger tubercles white to yellowish tan, tubercles on mesial surface of palm white, all other tubercles on palm royal blue to purple, main spine on carpus white. Antennal and antennule segments blue, antennal scales blue ending distally with white to cream colored spine, eye stalks blue-green, eye black, rostrum and postocular ridges outlined in cream to white. Abdominal segments dorsally dark blue to almost black with lateral margins of pleura royal blue. Cephalic areas of telson and uropods royal blue, more distal areas lighter blue changing to golden brown, spines on lateral ramus of uropod tan, large spines on mesial ramus of uropod blue at base, pink or reddish at tip. Venter of body and all legs straw to white in color. Most setae on the body golden-straw to brown in color.

Variation in color and color pattern in P. holifieldi was less than in other Hagenianus Group taxa, however, only one population of P. holifieldi was examined. In this species, the greatest color variation occurs in the abdomen and carapace, where some individuals have some brown color bleeding through the blue base color, whereas other individuals are predominantly blue. There is some variation in the intensity of the blue base color from royal blue to indigo to purple. There is also some variation in the color of the chelae from light cream to blue or purple.

Disposition of types. The holotype, allotype, and morphotype are deposited in the Illinois Natural History Survey Crustacean Collection, Champaign, IL (catalogue numbers, respectively, as INHS 14888, INHS 14890, and INHS 14889), respectively. The following collection of paratypes have been deposited at the Illinois Natural History Survey Crustacean Collection, Champaign, IL (catalogue number INHS 14891). The following paratypes have been deposited at the National Museum of Natural History, Smithsonian Institution, Washington, D.C. (catalogue numbers USNM 1283165 and USNM 1283166).

Size. The largest specimen in this study was a female having a TCL of 37.7 mm (PCL 32.8 mm). The largest first form male had a TCL of 32.7 mm (PCL 29.1 mm). The smallest first form male had a TCL of 29.3 mm (PCL 25.2 mm). No ovigerous females or females carrying young were collected.

Type locality. Burrows along power line right of way on private property, 2.2 Km SE of junction State Route 5 and County Road 38, Perry County, Alabama (32.5435N; - 87.3298W). The burrows were in the Bogue Chitto drainage, a tributary of the Cahaba River in the Alabama River drainage.

Range and specimens examined. Procambarus holifieldi is currently known only from the immediate area of the type locality. All known specimens were from collections made on three different dates from this location. Undoubtedly, this species will be collected from other locations within Perry County.

A total of 23 adults was examined for this study. The collection dates, collectors, and disposition of specimens are as follows: April 12, 2009, J. Holifield and M. Buntin, paratypes UNSM 1283166 3MI, 2F, 1 juv M, 3 juv F; April 15, 2009, M. Buntin, USNM 1283165 3 MII, 2F; February 10, 2010, M. Buntin, J. Holifield, G.A. Schuster, C.A. Taylor, paratypes INHS 14891 1MII, 1F; January 28, 2011, J. Holifield, holotype INHS 14888, allotype INHS 14890, morphotype INHS 14889, paratypes USNM 1283166, 2MI, 1MII, 5F.

Etymology. Named in honor of Jesse Holifield, from the Alabama Biodiversity Center in Marion, AL. Mr. Holifield has been an ardent collector of crayfishes in Perry County and was responsible for making this new species known to us. He collected most of the specimens used in this study.

Habitat and life-history notes. Procambarus holifieldi is a primary burrower. The habitat is a field spanning the width of a power line easement. Soils in the southwestern part of Perry County are from the Vaiden-Okolona- Sucarnoochee Soil Unit ( Harris, 1998). The site is located on the Blackland Prairie. Soils in this area are mostly Sucarnoochee soils, which are characterized as somewhat poorly drained. Seasonally high water table ranges from 15 to 45 cm below the surface from January to April ( Harris, 1998). This soil is known for flooding, wetness and very slow permeability. Numerous burrows were seen along this right of way. Several burrows were excavated by the authors and found to be fairly complex in structure with a main channel leading from a mud chimney at the surface. The main channel may have several side channels that open to the surface. During periods of soil saturation the ground water is just a few centimeters below the soil surface. No additional life history information is known for this species.

Crayfish Associates. Fallicambarus fodiens and an unidentifiable Procambarus sp. were also collected at the type locality.

Variation. Variation found within the 23 adult specimens examined is minimal for most characters. Characters that were consistent include the following: 1) Females with first pleopod present but reduced in size; 2) Areola linear and obliterated in all individuals; 3) Inner ramus of uropods with large spines extending beyond margin; 4) Numerous small round tubercles cover the lateral hepatic and branchiostegal surfaces of the carapace, dorsally carapace is smooth except for large punctations scattered throughout; 5) Distinct excision at base of dactyl.

Characters for which some variation was noted include the following: 1) Length of palm of chela ranges from 70.2–88.1% of width; 2) Length of dactyl of chela ranges from 59.0–63.7% of length; 3) Mesial row of tubercles on palm of chela ranges from 5–7, second row ranges from 2–6; 4) Number of tubercles on opposable surface of dactyl in excision area ranges from 2–3, last tubercle usually the largest, number of tubercles distal to excision area ranges from 2–5 with minute denticles in between, tubercles usually progressively smaller distally; 5) Number of tubercles in excision area of propodus ranges from 3–6, distal to excision area 3–5, usually progressively smaller distally with small denticles in between; 6) Usually one large spine on dorsal surface of carpus, some specimens with 1 large spine and 1–2 smaller spines; 7) Setae of third maxilliped in both first and second form males very long and dense and cover lateral and dorsal surfaces of all basal segments, slightly less dense on more distal segments, in females dorsal setation as in males, but lateral setation less dense and setae much shorter so lateral surfaces of segments visible; 8) Width of annulus ventralis of female ranges from 1.7 to 2.8 mm with mean of 2.2 mm, number of tubercles on ventral surface of annulus seems to vary and increases with size and maturity of female.

Relationships. Based on the shape of the caudal process, this species seems to be most closely related to P. barbiger . Both species have a distinctly triangle-shaped caudal process ( Figure 4 A & B), best seen in lateral view; it comes to a sharp point distally, as opposed to all other Hagenianus Group taxa ( Figure 4 C) where the caudal process in lateral view is subrhomboidal with the distal edge linear. There are a number of morphological differences between P. holifieldi and P. barbiger ( Figure 4 A & B). The caudal process in P. holifieldi is in the form of an acute triangle that is distinctly shorter than the central projection ( Figure 4 A). In P. b ar b i g e r the caudal process is in the form of an obtuse triangle and is subequal in length to the central projection ( Figure 4 B). The central projection in P. holifieldi is very wide and distinctly twisted in lateral view ( Figure 4 A), while in P. b ar b i g e r it is narrower, mostly straight and only curves near the distal end ( Figure 4 B). Lastly, P. holifieldi lacks the beard on the mesial margin of the palm of the chela ( Figure 1 N), and P. b ar b i g e r has a thick conspicuous beard ( Figure 13 M).

Common name. The suggested common or vernacular name for this species is Celestial Crayfish because of the deep blue base color that blends to violet and purple on the chelae, and its ethereal appearance.

Conservation status. Although other collecting has been done for primary burrowers in the vicinity of the type locality in Perry County, no additional populations have been found. It is clear that additional fieldwork needs to be done to better assess the distribution of this species and its current status. However, based on the criteria of the American Fisheries Society as outlined by Taylor et al. (2007) and the system developed by The Nature Conservancy/NatureServe ( Master, 1990), we propose that this species, because of its apparent narrow range, be considered Endangered (E) with a G1 global ranking. Assuming that additional populations of P. holifieldi will be found in Perry Co., the species would rank as Vulnerable by the International Union for the Conservation of Nature (IUCN) under Criteria D2.

Figures

FIGURE 1. Procambarus (Girardiella) holifieldi n. sp.: A. lateral view of carapace; B – E, respectively, mesial, lateral, caudal and cephalic view of terminal end of left gonopod of form I male; F – G, mesial and lateral view of terminal end of left gonopod of form II male; H, mesial view of entire left gonopod of form I male; I, dorsal view of tail fan; J, epistome; K, dorsal view of carapace; L, annulus ventralis; M, antennal scale; N, dorsal view of right chela and carpus of form I male; A – D, H – K, M – N from holotype; F – G from morphotype; L from allotype. CP = central projection, CaP = caudal process, MP = mesial process, S = Shoulder, CeP = Cephalic Process.

FIGURE 2. Procambarus (Girardiella) holifieldi n. sp.: Holotype, Perry County, AL.

FIGURE 3. Procambarus (Girardiella) holifieldi n. sp.: A – C, color variations, Perry County, AL.

FIGURE 4. Morphological differences between Procambarus (Girardiella) holifieldi n. sp., Procambarus barbiger and Procambarus hagenianus hagenianus in the elements of the form I male gonopod in lateral view, respectively, in A – C. CP = central projection, CaP = caudal process, MP = mesial process.

FIGURE 13. Procambarus (Girardiella) barbiger: A. lateral view of carapace; B – E, respectively mesial, lateral, caudal and cephalic view of terminal end of left gonopod of form I male; F – G, mesial and lateral view of terminal end of left gonopod of form II male; H, mesial view of entire left gonopod of form I male; I, epistome; J, dorsal view of carapace; K, annulus ventralis; L, antennal scale; M, dorsal view of right chela and carpus of form I male; A – E, H – J, L – M from Rankin County, MS (MMNS 00739); F – G from Jasper County, MS (MMNS 01611) and K from Rankin County, MS (MMNS 00739). CP = central projection, CaP = caudal process, CeP = cephalic process; MP = mesial process; s = shoulder.

Tables

TABLE 1. Measurements (mm) of type specimens of Procambarus holifieldi, new species

	Holotype	Allotype	Morphotype
Carapace Height Width Total length of carapace (TCL) Postorbital carapace length (PCL)	12.9 12.4 29.4 26.2	15.5 16.1 35.1 31.5	12.7 12.3 28.2 24.7
Areola Length	12.0	14.2	11.7
Eye Diameter	1.5	1.8	1.6
Rostrum Width Length	4.1 4.1	5.1 5.9	3.6 4.4
Chela Length, mesial margin palm Width, palm Length, lateral margin Length, dactyl	7.7 9.6 20.0 12.0	8.4 10.4 21.8 13.4	5.9 8.9 19.0 12.1