Creaserinus limulus, Johnson & Stern & Crandall, 2021

Johnson, Daniel P., Stern, David B. & Crandall, Keith A., 2021, The genus Creaserinus Hobbs, 1973 (Decapoda: Cambaridae) in Texas, Zootaxa 5017 (1), pp. 1-84 : 65-72

Creaserinus limulus n. sp.

Figs. 4, 5, 6c, i, 7d, h, 8a, c, f, 9–12, 35–38, Tables 1 , 5, 9, 12, 14, 17, 29, 30

Cambarus hedgpethi .— Reimer, 1969:53, Figs. 2, 39 [in part].

Fallicambarus hedgpethi .— Hobbs, 1969:111 [in part; by implication].

Fallicambarus (Creaserinus) hedgpethi .— Hobbs, 1973:463 [in part; by implication].

Fallicambarus (Creaserinus) fodiens .— Hobbs & Robison, 1989:672, Figs. 9d–g [in part].

Fallicambarus (Creaserinus) fodiens “AR-3”.— Ainscough et al., 2013:8, Figs. 3, 4.

Creaserinus fodiens .— Crandall & De Grave, 2017:627 [in part].

Diagnosis. Adults with rostrum devoid of marginal spines. Areola obliterated along part of its length. Antennal scale more than twice as long as broad. Cheliped with sufflamen. Lateral margin of chela costate, dorsal surface lacking tubercles on lateral half, ventrolateral surface lacking arched row of prominent setiferous punctations; opposable margin of dactyl with distinct excision in basal half; mesial margin bearing at least 2 rows of tubercles, those of main row extending from base at least two-thirds length of finger. Length of carpus distinctly less than width of palm of chela. Ventral surface of merus with mesial and lateral rows of tubercles. Mesial surface of chela of 2 nd pereiopod bearing prominent tufts of plumose setae. Hooks on ischia of 3 rd pereiopod only. Boss on coxa of 4 th pereiopod, rounded, slightly compressed and scarcely protruding ventrally. Gonopod of form I male lacking proximomesial spur and terminating in two distinct parts (mesial process and central projection). Central projection corneous, bladelike, lacking subapical notch, recurved 165–190° to axis of shaft, with distal part directed caudoproximally or cephaloproximally with tip never crossing central projection of corresponding gonopod, and base not inclined laterally, length 35.5–41.5% (x = 38.6, s = 1.7, n = 17) of total gonopod length. Mesial process noncorneous, recurved 130–175° to axis of shaft, proximal half inflated. Proximal gap between processes absent or very reduced. Uropodal endopod with distolateral spine; distomedian spine premarginal. Telson divided with spine on anterolateral flank of suture. Function 6 positive when b refers to Creaserinus limulus n. sp. and a refers to any of other five Texas species (refer to Tables 5, 9, 12, 14, and 17). Sex ratio of juvenile population (<16 mm CL) strongly skewed female or not.

FIG. 35. Creaserinus limulus n. sp.: (a) lateral and (b) dorsal views of paratopotypic female. Specimen exhibits broad-striped phase.

Holotypic male, form I. Eyes pigmented and with faceted cornea, but small. Body subcylindrical, weakly depressed. Abdomen narrower that cephalothorax (13.1 and 15.9 mm, respectively). Greatest width of carapace near one-third length of areola from cervical groove, where slightly greater than height (15.9 and 14.4 mm, respectively). Areola obliterated over most of its length and comprising 40.9% of CL and 48.1% of POCL. Rostrum with slender, slightly convex margins converging from base to weakly delimited acumen; apex corneous, distinctly upturned, and reaching ultimate podomere of antennular peduncle; dorsal surface concave with few, very weak punctations. Subrostral ridge weak but visible in dorsal aspect to base of acumen. Postorbital ridge slender, well defined, and relatively abruptly terminating anteriorly just posterior to margin of orbit. Cervical spine absent. Branchiostegal tubercle obtuse and weak. Suborbital angle obtuse and weak. Carapace punctate dorsally and weakly granulatepunctate laterally.

FIG. 36. Creaserinus limulus n. sp.: (a) dorsal, (b) ventral, (c) lateral, and (d) mesial views of chela; (e) tail; (f) antennal scale; (g) ventral view of merus, (h) proximal podomeres of pereiopods showing hook; and (i) annulus ventralis. a–h from holotype, i from allotype.

Abdomen subequal in length to carapace (31.4 and 32.1 mm, respectively); pleura small with subrounded margins; pleuron of 2 nd segment clearly overlapping that of 1 st. Telson divided and deeply incised laterally; right caudolateral angle of cephalic section with pair of spines, more mesial one movable (left with additional immovable spine mesial to others).

Cephalic lobe of epistome subtriangular, lacking punctations, margins distinctly elevated and smooth ventrally; main body with fovea. Ventral surface of proximal podomere of antennule with spine at three-fifths length. Antennal peduncle without spines, flagella reaching 2 nd abdominal segment. Antennal scale (Fig. 36f) reaching tip of acumen and ultimate podomere of antennular peduncle; lamella broadly rounded distomesially, broadest at three-fourths length, and broader than thickened lateral part. Mandible with cephalic noncorneous, incisor-like molar process and caudal corneous, irregular molar process. Ventral surface of ischium of 3 rd maxilliped with long setae mesially and medium-length setae laterally; mesial half of ventral surface of basis bearing long setae.

Right chela of cheliped (Figs. 36a–d) 2.3 times as long as broad, strongly depressed; width of palm 1.7 times length of mesial margin. Latter bearing main row of 8 (left with 7) tubercles, flanked dorsolaterally by 3 rows of 7 (left with 7), 9 (left with 9), and 1 (left with 8) successively smaller tubercles, and ventrolaterally by row of 4 smaller tubercles (left with 4). Dorsal surface of palm and fingers bearing setiferous punctations, those of dactyl and fixed finger much more distinct. Lateral margin of propodus costate along distal two-thirds, but broadly rounded proximally. Ventral surface punctate, with punctations more prominent on fingers, single tubercle on margin opposite base of dactyl with row of 3 smaller ones situated proximolaterally to it. Long conspicuous setae present on proximal two-thirds of opposable margin of fixed finger. Dorsal and ventral surfaces of both fingers with well-defined ridges flanked by punctations. Opposable margin of fixed finger with row of 6 (left with 6) tubercles along proximal three-fourths, 2 nd and 3 rd from base largest, 6 th situated more ventrally; single row of minute denticles extending from 3 rd tubercle to corneous tip of finger. Opposable margin of dactyl with prominent excision in proximal third; 2 tubercles borne within excision, a larger one at its distal extremity, and 5 (left with 4) distal to excision; single row of minute denticles extending from 2 nd distalmost tubercle to corneous tip of finger. Mesial margin of dactyl with main row of 13 (left with 13), tubercles flanked dorsolaterally by 2 rows of 7 (left with 9) and 2 (left with group of 2) successively smaller tubercles (left with single tubercle ventrolateral to main row).

Carpus of cheliped 1.5 times as long as broad and 1.3 times as long as palm mesial margin; dorsal surface with longitudinal median trough, flanked with punctations; mesial surface tuberculate with large spine on distal margin; lateral and ventral surfaces punctate; ventral surface of right carpus lacking large distomedian spine (present on left). Merus with single (left with 2) weak tubercle near dorsodistal extremity; mesial and lateral surfaces sparsely punctate; ventral surface (Fig. 36g) with mesial row of 12 tubercles (left with 14), lateral row of 4 (left with 5), and distal row of 2 (left with 3) weak tubercles. Ischium sparsely punctate with 1 weak tubercle ventromesially (left with row of 3).

Second pereiopod bearing conspicuous long setae on dorsal and ventral margins of chela and carpus, and proximal half of ventral margin and dorsodistal extremity of merus, and dense mats of plumose setae on mesial faces of palm and carpus.

Hook (Fig. 36h) on ischium of 3 rd pereiopod simple, reaching level of basioischial articulation, and not opposed by tubercle on corresponding basis. Coxa of 4 th pereiopod as in “Diagnosis.” Coxa of 5 th pereiopod lacking boss.

Gonopod (Figs. 37a, c, e) almost reaching midlength coxa of 3 rd pereiopod when abdomen flexed and substantially obscured by setae extending from surrounding sternum; shaft of appendage slightly arched, otherwise as in “Diagnosis.” Proximal podomere of uropod with both lobes bearing single small spines; endopod with distolateral spine and distinctly premarginal distomedian spine.

Allotypic female. Differing from holotype in nonsecondary sexual characters as follows: abdomen slightly wider that cephalothorax (14.3 and 13.8 mm, respectively); areola comprising 39.2% of CL and 45.7% of POCL; small branchiostegal tubercle present; abdomen longer than carapace (33.3 and 28.6 mm, respectively); caudolateral angle of cephalic section of telson with 2 spines; cephalic lobe of epistome subpentagonal; right chela of cheliped 2.2 times as long as broad; long conspicuous setae present on proximal half of opposable margin of fixed finger; palm mesial margin with main row of 8 (left with 9) tubercles, dorsolaterally flanked by 2 rows of 6 (left with 7) and 4 (left with 2) and ventrolaterally by row of 3 (left with 3); opposable margin of fixed finger with row of 5 (left with 5) tubercles, 2 nd and 4 th (2 nd and 3 rd on left) from base largest, 5 th situated more ventrally; mesial margin of dactyl with main row of 14 (left with 11) tubercles, bordered dorsolaterally by two rows of 5 (left with 6) and 7 (left with 9) and ventrolaterally by row of 0 (left with 2); carpus of cheliped 1.3 times as long as broad and 1.5 times as long as palm mesial margin; ventral surface of with large distomedian spine; merus of cheliped with 3 (left with 2) weak tubercles near dorsodistal extremity, ventral surface with mesial irregular row of 14 tubercles (left with 15), lateral row of 7 (left with 7), and 1 (left with 0) rudimentary tubercle in position of distal row; ischium of cheliped with ventromesial row of 5 weak tubercles (left with 5); second pereiopod with only sparse plumose setae on mesial faces of palm and carpus.

Annulus ventralis (Fig. 36i) 1.3 times as broad as long, cephalically fused to sternum. Caudal and lateral margins elevated (ventrally) and surrounding shallow, cephalic, caudodextrally-directed trough. Short sinus originating at caudomedian extremity, curving sinistrally 45°, then dextrally 180°, before terminating under dextral wall. Postannular sclerite subelliptical, half as wide and two-fifths as long as annulus. First pleopod present.

Morphotypic male, form II. Differing from holotype in following respects: areola comprising 37.7% of CL and 44.9% of POCL; abdomen slightly longer than carapace (27.2 and 25.7 mm, respectively); caudolateral angle of cephalic section of telson with single immovable spine; cephalic lobe of epistome subsemicircular; flagellum of antenna reaching 3 rd abdominal segment; right chela of cheliped 2.1 times as long as broad; mesial margin of palm bearing main row of 7 (left with 8) tubercles flanked dorsolaterally by row of 8 (left with 6) slightly smaller tubercles which bordered by additional 13 (left with 14) even smaller scattered tubercles, and row of 4 smaller tubercles (left with 4) on ventrolateral flank of main mesial row; lateral margin of propodus costate along distal three-fourths; opposable margin of fixed finger with row of 5 (left with 5) tubercles along proximal three-fourths, 2 nd and 3 rd from base largest, 5 th situated more ventrally; opposable margin of dactyl with 5 (left with 6) tubercles distal to large tubercle delimiting excision; mesial margin of dactyl with main row of 15 (left with 13) tubercles bordered dorsolaterally by row of 7 (left with 10) smaller tubercles, but without dorsolaterally-bordering 2 nd row (left with row of 2); carpus of cheliped 1.4 times as long as broad and 1.4 times as long as palm mesial margin; merus of cheliped with 3 (left with 4) weak tubercles near dorsodistal extremity, ventral surface with mesial row of 16 tubercles (left with 15), lateral row of 7 (left with 5), and distal row of 3 (left with 3) weak tubercles; ischium of cheliped with ventromesial row of 3 weak tubercles (left with 5); second pereiopod with plumose setae on mesial faces of palm and carpus weakly developed; hook on ischium of 3 rd pereiopod and boss on coxa of 4 th pereiopod both reduced; gonopod (Figs. 37b, d) with central projection noncorneous, both processes more inflated, central projection recurved 160°, mesial process 145°.

FIG. 37. Creaserinus limulus n. sp.: (a) mesial, (c) ventral, and (e) lateral views of gonopod of holotype; and (b) mesial and (d) lateral views of gonopod of morphotype.

Type locality. United States Highway 271, 1.3 km (0.8 mi) south County Road 1820, Titus County, Texas (33.32692, -95.09377). Roadside pool 15 x 5 x 0.25 m in size. Adjacent area oak woodland mixed with cleared areas .

Disposition of types. The holotype, allotype, and morphotype (nos. 1640958, 1640959, and 1640960, respectively) are deposited in the National Museum of Natural History , Smithsonian Institution. All paratypes remain in DPJ’s collection .

Size. Of 17 form I males for which measurements were made, carapace lengths range from 23.1 to 32.1 (x = 26.7) mm.

Range and specimens examined. Creaserinus limulus n. sp. has been found at 63 sites in 13 Texas counties (Fig. 10), of which 17 (27.0%) are represented by at least one form I male and 31 (49.2%) are represented in the molecular phylogeny. In addition, samples JC2733, JC2738, JC2776, and Figs. 9d–f (also possibly 8e′, f′, and 9c) of Hobbs & Robison (1989:674–675) all indicate its presence in Arkansas, as does Fig. 9g of the latter for Oklahoma. The presence in Arkansas is also suggested by the observations of highly skewed sex ratios Hobbs & Robison (op. cit.:683) reported for Fallicambarus (Creaserinus) fodiens from Sevier County. Pflieger (1996:70) also noted a highly skewed sex ratio for the limited collections of Fallicambarus fodiens from Missouri, suggesting the possibility that the range may extend considerably to the northeast; although the drawing of the form I male gonopod depicted for the species is inconsistent with that of Creaserinus limulus n. sp. Given that only one adult male was collected from Missouri, the form of which was not noted, it’s questionable whether that drawing is of a Missouri specimen.

Bowie: 33.3174, 94.7231, I, 4/11/08; 33.5231, 94.2703, I, 4/12/08; 33.5985, 94.4970, I; 33.5314, 94.4075, I, 4/18/14, DJ387, DJ535; 33.5410, 94.4638, DJ375; 33.5673, 94.6194, DJ540; 33.6278, 94.6201, DJ376; 33.5915, 94.6544; 33.5173, 94.7057, 4/19/14; 33.4772, 94.6008, I; 33.3935, 94.4276, I, 4/20/14; 33.3861, 94.4977, DJ384; 33.3323, 94.5311; 33.3355, 94.5283; 33.2909, 94.5934, I, DJ538; 33.3487, 94.6147, I; 33.4310, 94.5762; 33.2976, 94.3918, I; 33.2984, 94.2940, I, DJ476; 33.3591, 94.3406. Cass: 32.9614, 94.1872, I, 4/10/15, DJ617; 33.2082, 94.0990; 33.1105, 94.1841; 33.0699, 94.0609, I. Franklin: 33.2700, 95.2376, 4/5/14, DJ357; 33.3238, 95.2497; 33.2758, 95.1843. Harrison: 32.3771, 94.3290, 4/10/15; 32.4600, 94.0709; 32.6177, 94.1476. Hopkins: 33.1831, 95.5896, I, 4/25/08; 33.1668, 95.4937, 4/5/14, DJ355; 33.2025, 95.4938, DJ515; 33.2040, 95.4938, DJ536; 33.2367, 95.4326, DJ356; 33.2258, 95.5551. Panola: 32.2132, 94.4323, 5/2/14, DJ388; 32.1728, 94.0613; 32.0407, 94.5626; 32.2799, 94.4406, 4/12/15. Rains : 32.7820, 95.7969 , 6/13/14, DJ449. Red River : 33.6191, 94.7615 , 4/18/14, DJ377; 33.7050, 94.9396, DJ378; 33.7726, 94.9232, DJ379; 33.8329, 95.0361, DJ380; 33.8213, 95.0386, DJ532; 33.9332, 95.1696, 4/19/14, DJ381; 33.8418, 95.2648, DJ382; 33.4887, 95.1466, DJ383; 33.5144, 95.0997, I, DJ513; 33.4985, 95.0521, DJ531; 33.4344, 94.7812, DJ534; 33.5300, 94.7816, DJ537; 33.5386, 95.1898; 33.3970, 95.2421, 4/25/15. Rusk : 32.3626, 94.5958 , 4/12/15. Smith : 32.4450, 95.0326 , 4/11/15. Titus : 33.3436, 94.9024 , I, 4/13/08; 33.3269, 95.0938, I, 4/5/14, DJ385; 33.3293, 95.0352, I. Upshur: 32.8593, 94.9668, 4/8/11. Wood : 32.7265, 95.4399 , 4/4/14, DJ354; 32.8003, 95.5415, 4/4/16.

FIG. 38. Creaserinus limulus n. sp.: mesial views of gonopods of form I male paratypes. Each photo annotated with name of county where collected.

Variations. Variations in a number of key morphometrics and meristics may be found in Tables 5, 9, 12, 14, and 17. Additional variations not found in those tables are provided here. All are based on form I males, unless otherwise noted. The rostral margins vary from straight and moderately to weakly converging, to strongly convex, to slightly concave, with an acumen varying from moderately delimited to undelimited. The rostrum L/W ratio ranges from 1.2 to 1.5 (x = 1.4, s = 0.1, n = 17). The ratio of the rostrum L to CL ranges from 16.6 to 20.3% (x = 18.7, s = 1.1, n = 17). The cervical tubercle is always very small but is frequently nearly imperceptible. The branchiostegal spine ranges from small to absent. The suborbital angle varies from small and obtuse to entirely obsolete. The caudolateral angle of cephalic section of telson is occasionally missing one of the movable spines. The anterior lobe of the epistome varies in shape from triangular to subtriangular to subsemicircular. Ranges in numbers of tubercles on various podomeres of the cheliped include the following: 11–15 (x = 13.1, s = 1.0, n = 25) in the main row of the dactyl’s mesial margin, 7–10 (x = 8.2, s = 1.0, n = 25) and 0–6 (x = 2.5, s = 1.7, n = 11) in the 2 rows dorsolaterally flanking it, and 0–5 (x = 1.6, s = 1.6, n = 11) in the row ventrolaterally flanking it; 6–10 (x = 7.7, s = 1.0, n = 25) in the main row of the palm’s mesial margin, 4–9 (x = 6.8, s = 1.1, n = 25) and 0–9 (x = 3.0, s = 3.4, n = 11) in the 2 rows dorsolaterally abutting it, and 1–6 (x = 3.5, s = 1.4, n = 11) in the row ventrolaterally abutting it; 12–16 (x = 14.0, s = 1.3, n = 13) and 4–8 (x = 5.5, s = 1.3, n = 13) in the merus’s ventromesial and ventrolateral rows, respectively; and 1–4 (x = 2.7, s = 1.2, n = 13) in the ischium’s ventromesial row. The 2nd pereiopod of one individual was lacking a beard, presumably due to regeneration. Figure 38 illustrates variation in the form I male gonopod. The caudal offset of the MP ranges from distinctly greater than (Fig. 38m) to distinctly less than (Fig. 38b) that of the CP. The tip of the MP may be acuminate (Fig. 38i) or blunt (Fig. 38g). The angle of recurvature of the CP ranges from 165° (Fig. 38m) to 190° (Fig. 38l), while that of the MP ranges from 130° (Fig. 38d) to 175° (Fig. 38b). The proximal gap between the processes varies from nonexistent (Fig. 38e) to slight (Fig. 38a). The degree of caudal arch of the gonopod shaft ranges from slight (Fig. 38a) to moderate (Fig. 38l). The annulus ventralis never occurs as a mirrored image of that of the allotype.

Life history notes. Seasonal collection data of Creaserinus limulus n. sp. is provided in Table 30 . Virtually all collections were in April, limiting the ability to interpret seasonal patterns from the data, although the data for that month seems consistent with that of the genus as a whole (refer to its “Life history notes” for discussion). The more northern distribution of this species may result in delayed reproduction compared to its congeners due to the cooler climate. A single female with a CL of 23.7 mm was found carrying 50 young on 5 April 2014. No ovigerous females have been found.

As previously noted, a majority of the collections of this species have been composed mostly or entirely of females. The biological cause of the great preponderance of females is unknown. While collecting this species at sites where females greatly predominated, the few males found were often among the smallest individuals. The scenario repeated enough that it provided a technique for finding males: look for small specimens! The presence of males mostly at only small sizes could be either due to higher death rates of young males compared to females, or perhaps to seasonal differences in sex ratio production, with early all-female production, followed by later production which produces both sexes. Under the hypothesis that much of the reproduction is parthenogenetic, several adult females in glair, collected on 18 Apr 2014 from a site where only females were found (67 of them!), were returned to the laboratory with hopes they might oviposit there. All were maintained alive for seven months, during which two molted and none produced eggs.

Ecological notes. This crayfish has been found in pine woods, oak woods, deciduous woods, mixed woods, woodland/grassland mosaic, and grassland. It has been collected from roadside ditches and pools, bottomland pools, swales, ephemeral streams, permanent streams (uncommonly), and marshes. Water may be clear, turbid, or tannin stained. Water bodies may or may not contain hydrophytic vegetation. Of three excavated burrows for which notes were taken, one had a single, vertical shaft extending to 5 dm depth; a second had a single shaft angled 30° from vertical that extended to 5 dm depth; and a third was Y shaped with two entrances 3 dm apart, with the junction of their respective tunnels at 1.5 dm depth, below which a vertical tunnel extended to an ultimate depth of 6 dm.

Etymology. Limulus (L.) = skewed, alluding to the highly skewed sex ratios typical of this species.

Crayfish associates. Collected with Creaserinus limulus n. sp. were the following 14 crayfish taxa: Faxonella blairi (n = 26, 41.3%), Procambarus (Ortmannicus) acutus (n = 24, 38.1%), Procambarus (Girardiella) curdi (n = 18, 28.6%), Faxonella beyeri (n = 8, 12.7%), Creaserinus brevistylus (n = 4, 6.3%), Procambarus (Girardiella) kensleyi (n = 4, 6.3%), Cambarellus (Pandicambarus) shufeldtii (n = 2, 3.2%), Lacunicambarus ludovicianus (n = 2, 3.2%), Procambarus (Girardiella) simulans (n = 2, 3.2%), Creaserinus clausus (n = 1, 1.6%), Cambarellus (Pandicambarus) puer (n = 1, 1.6%), Faxonius palmeri longimanus ( Faxon, 1898) (n = 1, 1.7%), Procambarus (Scapulicambarus) clarkii (n = 1, 1.6%), and Procambarus (Girardiella) steigmani Hobbs, 1991 (n = 1, 1.6%).