Orconectes mississippiensis

Orconectes mississippiensis (Faxon)

Cambarus Mississippiensis Faxon, 1884:123–126, 146; 1885a: 85, 86, 101–102, 104, 105, 108, 161, 168, 173, pi. III: fig. 2, pi. X: fig. 4, 4,’ 4a, 4a.′—Underwood, 1886:370.

Cambarus mississippiensis.—Hay, 1899:960, 962.—Ortmann, 1902:278, 1905:110, 111, 114, 117; 1931:90, 94.—Harris, 1903:59, 108, 138, 144, 151, 153.—Faxon, 1914:383, 422.

Cambarus (Faxonius) mississippiensis.—Ortmann, 1905:113.—Lyle, 1938:76.

Faxonius mississippiensis.—Creaser, 1933a:3 [by implication].

Faxonius (Faxonius) mississippiensis.—Creaser, 1933b:21 [by implication].

Orconectes mississippiensis.—Hobbs, 1942a:352 [by implication]; 1968:K13, K28, fig. 31e; 1972:149 [not p. 80, fig. 63a, see O. chickasawae]; 1974:35, fig. 161.—Penn, 1957: 236.—Fitzpatrick and Payne, 1968:20.—Payne, 1972:27.

Orconectes (Orconectes) mississippiensis.—Hobbs, 1942b:154 [by implication]; 1959:892.

DIAGNOSIS.—Body and eyes with pigment. Rostrum without median carina, acumen in adults seldom delimited basally by marginal tubercles. Areola obliterated along part of its length and comprising 28.8 to 33.2 percent of total length of carapace (38.3 to 41.8 percent of postorbital carapace length). Cervical spine small or tuberculiform; suborbital angle at most vestigial; postorbital ridge moderately well developed with small spine or tubercle cephalically. Antennal scale approximately 2.3 times as long as wide, broadest at or distal to midlength. Chela depressed, lateral margin costate, tubercles on mesial margin forming subserrate row; fingers gaping and mesial margin of dactyl with subserrate (in silhouette) row of tubercles along at least basal two-thirds; opposable margin of dactyl with distinct excision in proximal third. Hook on ischium of third pereiopod of male. First pleopod of first form male without angular shoulder on cephalic surface, with rami almost straight proximally and curved distally, reaching midlength of coxa of second pereiopod when abdomen flexed; pleopod length divisible into carapace length 2.8 to 3.2 times; terminal elements slender and subparallel; central projection constituting about 31.5 to 36.6 percent of entire length of pleopod, bladelike, and tapering from base to caudodistally directed apex; mesial process subcylindrical in section proximally, troughlike distally, its tip directed almost caudally, and reaching about same level caudally as central projection. Annulus ventralis as figured. First pleopod present in female.

SYNTYPIC MALE, FORM I.—Body and eyes pigmented. Cephalothorax (Figure 11a,k) subovate in section; abdomen narrower than carapace (14.5 and 17.1 mm), width of latter greater than depth at caudodorsal margin of cervical groove (17.1 and 15.9 mm). Areola obliterated for some distance along cephalic half, its length constituting 29.9 percent of entire length of carapace (39.6 percent of postorbital carapace length). Rostrum with low, adpressed (particularly cephalically) borders gently converging from base to subangular contraction at base of acumen, there with minute corneous tubercle; tip of acumen reaching about midlength of ultimate podomere of antennular peduncle; upper surface of rostrum shallowly excavate with numerous small punctations. Subrostral ridge weak and barely evident in dorsal aspect from base almost to midlength of rostrum. Postorbital ridge moderately well developed, grooved dorsolaterally, and terminating cephalically in minute corneous tip. Cervical spine small; branchiostegal spine moderately well developed. Carapace punctate dorsally, rather strongly granulate laterally with larger granules concentrated cephaloventrally. Abdomen slightly shorter than carapace (35.7 and 36.5 mm); pleura well developed, with ventral borders broadly rounded; cephalic section of telson with 2 spines in each caudolateral corner. Proximal podomere of uropod with spine on each lobe, that on lateral one very small; both rami with median keel, that on mesial ramus ending in premarginal spine.

Cephalic lobe of epistome (Figure 11i) with cephalomedian projection, and delimited basally by contracted base; margins irregular, distinctly angular cephalolaterally, and elevated (ventrally), ventral surface with few scattered setae; main body of epistome with median longitudinal depression in which 2 foveae present, cephalic one more conspicuous; epistomal zygoma broadly arched. Basal podomere of antennule with prominent spine on ventral surface slightly distal to midlength. Antennal peduncle with spine on lateral surface of basis and another on ventral surface of ischium. Antenna broken. Antennal scale (Figure 11n) 2.7 times as long as wide with greatest width distal to midlength; mesial border of lamella rounded but with suggestion of angle mesiodistally and another at level of widest part; apical spine, although broken, probably reaching level of distal extremity of antennular peduncle. Ventral surface of third maxilliped with submarginal lateral row of long, plumose setae, lateral half of surface with scattered shorter ones, mesial half with stiff hairlike setae; distolateral extremity of ischium with subacute spine.

Right chela (Figure 11l) strongly depressed (ratio of depth to width 0.57), subequal in length to carapace (36.2 and 36.5 mm) and 2.6 times as long as wide; thickness slightly more than three-fourths as long as areola and almost four-fifths length of mesial margin of palm; latter with 6 tubercles in mesialmost row and 5 and 3 in flanking dorsal and ventral rows, respectively (left chela with 5, 6, and 3); additional tubercles, most arranged in irregular linear series, present on mesial half of dorsal surface, also few proximal to mesial base of fixed finger, remaining dorsal and lateral surfaces punctate; ventral surface of palm with 3 marginal tubercles at base of dactyl, arclike row of 4 proximolateral to them, and 2 proximolateral to arc, remaining surface punctate. Fingers gaping, moderately prominent row of plumose setal tufts along ventral side of opposable margin of fixed finger, margin bearing row of 16 tubercles (fourth from base largest and distal 5 minute) and single more ventrally situated one opposite thirteenth from base, row of minute denticles extending distally from level of more ventral tubercle to corneous tip of finger; dorsal surface with prominent submedian ridge, and smaller one present immediately lateral to row of tubercles on opposable surface, ridges flanked by rows of setiferous punctations; lateral costa extending proximally along finger and onto distal half of palm; ventral surface of finger punctate with submedian longitudinal ridge. Opposable margin of dactyl with row of 18 tubercles (fifth from base largest, marking distal end of excised area of finger, and distal 5 minute) and interrupted row of minute denticles extending distally from twelfth tubercle from base to corneous tip of finger; dorsal and ventral surfaces similar to those of fixed finger; mesial surface with cluster of tubercles along basal three-fifths of finger, contracting to single row approaching distal end of finger, in silhouette those along mesialmost margin forming subserrate row. Carpus about 1.8 times as long as broad with slightly sinuous dorsal sulcus flanked mesially by small tubercles and laterally by setiferous punctations; mesial surface with prominent spikelike tubercle, 2 smaller ones proximal to it, and another, more dorsally situated, lying proximomesial to articular eminence; ventral surface with 2 marginal tubercles, 1 on condyle, other submedian; 5 additional tubercles situated ventromesially. Dorsal surface of merus with 2 acute tubercles near distal end and 2 smaller ones proximal to them; ventral surface with lateral and mesial rows of 10 and 11 tubercles respectively; distolateral apophysis with spiniform tubercle, and few additional ones between rows. Ventromesial margin of ischium with 4 small tubercles.

Ischium of third pereiopod (Figure 11j) with simple hook, appearing almost bituberculate, overreaching basioischial articulation and opposed by tubercle on basis; hook heavy with broadly rounded distal extremity. Ventral membrane on coxa of fifth pereiopod studded with short setae.

First pleopods (Figure 11d,f, from syntypic male, form I; b,h,m, from male, form I, from Kemper County, Mississippi) symmetrical and reaching coxa of second pereiopod when abdomen flexed. (See “Diagnosis” for description.)

SYNTYPIC FEMALE (USNM 19760).—Differing from syntypic male, form I, in following respects: marginal spines present on rostrum; acumen reaching end of ultimate podomere of antennular peduncle; postorbital ridge ending cephalically in well developed spine; lateral surface of carapace much less granular; left antennal scale broadest almost at midlength. (Chela regenerated; following notes based on specimen collected from roadside ditch off U.S. Hwy 82 about 1 mile [1.6 km] east of Clayton Village [Starkville], Oktibbeha County, Mississippi.) Ratio of depth to width of chela 0.60, distinctly shorter than carapace (24.5 and 31.8 mm); mesial surface of palm with 4 tubercles in ventral row, 6 in middle, and 4 in dorsal; tubercles on ventral surface of palm differing in absence of 2 proximolateral ones and presence of 2 between margin and arclike row; opposable margin of fixed finger with row of 12 tubercles (sixth from base largest), large tubercle situated more ventrally between tenth and eleventh tubercles; opposable surface of dactyl with row of 13 tubercles (fourth from base largest); ventrolateral row of only 6 tubercles on merus; ventromesial margin of ischium with only 2 tubercles. (See Table 6.)

Annulus ventralis (Figure 11e) firmly but not inflexibly fused to sternum, somewhat diamond shaped in outline, about 1.6 times as broad as long; cephalomedian trough flanked by high ridges flaring laterally at about midlength of annulus where forming cephalic wall of centrally located depression; sinus originating at cephalomedian side of depression, extending caudosinistrally, and, after making hairpin curve and bending caudodextrally to median line, extending caudally before ending on caudal wall; tongue extending sinistrally. Postannular sclerite about 2.5 times as broad as long, slightly more than four-fifths as wide as annulus and about one-half as long. First pleopod reaching almost midlength of annulus when abdomen flexed.

SYNTYPIC MALE, FORM II.—Differing from syntypic male, form I, in following respects: rostrum with marginal spines; postorbital ridge with spine cephalically; chela with ratio of depth to width 0.60, length less than that of carapace (24.5 and 31.0 mm); mesial surface of palm of chela with 5 tubercles in ventralmost row, none proximal to arc of tubercles on ventral surface; opposable margin of fixed finger of chela with row of 13 tubercles, and single tubercle located more ventrally, between tenth and eleventh of row; opposable margin of dactyl with row of 19 tubercles; merus with ventrolateral row of 8; hook on ischium of third pereiopod reduced, not overreaching basioischial articulation. First pleopod (Figure 11c,g) with more robust rami, and cleft between conspiciously shorter. (See Table 6.)

COLOR

Orconectes mississippiensis (Faxon)

Cambarus mississippiensis Faxon, 1884:123; 1885a: 101, pl. 3: fig. 2; pl. 10: figs. 4, 4′, 4a, 4a′.

Cambarus (Faxonius) mississippiensis.—Ortmann, 1905c: 113.

Faxonius mississippiensis.—Creaser, 1933a:3 [by implication]; 1962:2 [by implication].

Faxonius (Faxonius) mississippiensis.—Creaser, 1933b: 19 [by implication].

Orconectes mississippiensis.—Hobbs, 1942a:352 [by implication].—Fitzpatrick, 1963:61 [by implication].

Orconectes (Orconectes) mississippiensis.—Hobbs, 1942b: 154 [by implication].

TYPES.—Syntypes, USNM 19760 (I, ), USNM 19759 (II, ), MCZ 3563 ().

TYPE-LOCALITY.—Eastern Mississippi. Restricted to Macon, Noxubee County, Mississippi, by Faxon (1914:422).

RANGE.—Eastern Mississippi.

HABITAT.—Streams and roadside ditches.

Orconectes (Gremicambarus) mississippiensis (Faxon)

Cambarus Mississippiensis Faxon, 1884:123; 1885a:101, pl. 3: fig. 2, pl. 10: figs. 4, 4′, 4a, 4a′.

Cambarus mississippiensis.—Hay, 1899b:960.

Cambarus (Faxonius) mississippiensis.—Ortmann, 1905c:113.

Faxonius mississippiensis.—Creaser, 1933a:3 [by implication]; 1962:2 [by implication].

Faxonius (Faxonius) mississippiensis.—Creaser, 1933b:19 [by implication].

Orconectes mississippiensis.—Hobbs, 1942a:352 [by implication]; 1974b:35, fig. 161.—Fitzpatrick, 1963:61 [by implication],—Cooper and Hobbs, 1980:35, figs. 11–13.

Orconectes (Orconectes) mississippiensis.—Hobbs, 1942b: 154 [by implication].

Orconectes (Gremicambarus) mississippiensis.—Fitzpatrick, 1987a:54.

TYPES.—Syntypes, USNM 19760 (male I, female), USNM 19759 (male II, female), MCZ 3563 (female).

TYPE LOCALITY.—Eastern Mississippi. Restricted to Macon, Noxubee County, Mississippi, by Faxon (1914:422).

RANGE.—“Limited to the Prairie Section of the Noxubee River basin and in other tributary systems of the Tombigbee River northward to the Catalpa Creek basin in Kemper, Noxubee, Lowndes, and Oktibbeha counties, Mississippi” (Cooper and Hobbs, 1980:40).

Orconectes mississippiensis er en art av ferskvannskreps innenfor slekten Orconectes (familie Cambaridae, orden Reptantia) som inngår i den store gruppen av såkalte tifotkreps. Dette er ferskvannskreps som på engelsk oftest kalles «crayfish».

Orconectes mississippiensis er en av de om lag 85 artene i slekten, og lever i elver og innsjøer nesten utelukkende i delstaten Mississippi.

Orconectes mississippiensis é uma espécie de crustáceo da família Cambaridae.

É endémica dos Estados Unidos da América.