Pacifastacus leniusculus klamathensis ( Stimpson, 1857 ), 1437

Pacifastacus leniusculus klamathensis ( Stimpson, 1857) View in CoL

( Figs. 3 View Figure 3 , 4 View Figure 4 ; Tab.1)

Description of male. (Male#3, SMF 1437). Cephalothorax ( Fig. 4A View Figure 4 ) subcylindrical; thoracic section dorsoventrally depressed, feebly tuberculated dorsally and dorsolaterally, cephalic section laterally with moderate tubercles. Rostrum ( Fig. 4B View Figure 4 ) non-serrate, margins converging from base to base of acumen, broad at base and lacking median carina, with moderately elevated, slightly thickened margins and tubercles, latter weakly converging to base of acumen, with single right side (left 1) weak marginal tubercles, more strongly converging and moderately concave to dorsally directed apex, tip of which reaching cephalic to distal margin of antennal scale and not reaching distal margin of penultimate podomere of antennular peduncle, length of acumen seldom equal to width of rostrum at level of marginal tubercles, floor (dorsal surface) of rostrum with small spots, suborbital ridge not visible in dorsal aspect, postorbital ridge rounded, poorly defined dorsally, with dorsolateral groove and not having tubercles at posterior bases.

Carapace 1.3 times wider than greatest width of abdomen, abdominal pleura with margins subangular ( Fig. 4D View Figure 4 ), terminal slightly rounded, surface punctate, terga slightly punctate, articular surfaces glabrous. Proximal podomere of uropod with small caudolateral spine on lobe, larger spine on mesial lobe, mesial ramus of uropod with moderate caudolateral spine, and strong median ridge terminating in moderate, submarginal caudomedian spine, lateral ramus of uropod with caudolateral spine.

Epistome ( Fig. 4E View Figure 4 ) with wide, nearly semicircular cephalic lobe bearing very small cephalomedian projection, lateral margins of lobe moderately thickened, slightly elevated ventrally, floor (ventral surface) of lobe plane, covered with very small marks, lacking setae; lamellae small, punctate, subtruncate lateral corners, lacking spine or ridge posterior to renal papilla; central depression of body broad, fovea weak, zygoma slightly arched, cephalolateral margins flanked by usual pits.

Third maxilliped with tip of endopodite nearly extending to distal margin of penultimate podomere of antennal scale peduncle; tip of basal podomere of exopodite extending beyond midlength of merus of endopodite; mesial margin of merus ( Fig. 4F View Figure 4 ) with two spines, spine of distal end larger; longitudinal ridge of ventrolateral margin of ischium with row of marks, ventrolateral half of ischium punctuate, distolateral corner with small tubercle, ventromesial half with long, obscuring bristles on mesial margin, latter with denticles, distomesial corner having larger spine.

Total length of cheliped 90.5 % of TCL, mesial margin of palm ( Fig. 4C View Figure 4 ) 1.3 times wider than deep, articular ridge strong, dorsal and ventral surfaces punctate, lacking tubercles, distolateral part with weak depression and moderate punctuations marks, not costate, articular ridge strong. Fingers of chela not gaping, lateral surface not costate and row of tubercles, dorsal surface and ventral surface with tuft of seta originating from marks, lacking longitudinal ridge, opposable surface of fixed finger with row of moderate tubercles. Fixed finger dorsolaterally very weakly costate, dorsal and ventral surfaces with tuft of seta originating from marks, lacking longitudinal ridge, opposable surface with row of conical and equal size tubercles. Dactyl of chelae 1.7 times as long as mesial margin of palm, comprising 57.4 % of total chela length, dorsal surface of dactyl lacking longitudinal ridge, mesial surface with seta originating from marks, ventral surface punctate, lacking ridge, opposable surface with single row of equal size tubercles. Dorsal surface of carpus with long,slightly oblique sulcus, surface lateral and mesial to sulcus punctate; mesial surface of carpus with large, strong tubercles; ventral surface with conical distal mounds, distomesial one tipped with spine. Merus of cheliped length 42.4 % of TCL.

Gonopods (first pleopods) ( Fig. 4G View Figure 4 ) of male symmetrical in caudal aspect.Second pleopod( Fig.4H,I View Figure 4 ) single stout shaft with deep suture near midlength, exopodite originating from suture not reaching distal margin of endopodite, palps originating on distal portion of shaft.

Examined specimen and type locality. In the original description, Stimpson (1857) noted that the type locality is Lake Klamath and collected by Dr.Newberry. The type series, however, is not extant, and Faxon (1914: 409) mentioned that “probably destroyed in the Chicago fire in 1871”.

Pacifastacus leniusculus klamathensis was originally described as Astacus leniusculus , then Bott (1950) revised their genus name into Pacifastacus based on the specimen SMF 1437, which was collected from Portland, Oregon ( Fig. 3 View Figure 3 ). The specimen is the namebearing type of the genus Pacifastacus .