Pycnogonum cranaobyrsa, Bamber, Roger N., 2004

Bamber, Roger N., 2004, with description of three new species, Zootaxa 458, pp. 1-12 : 9-11

Pycnogonum cranaobyrsa sp. nov.

Material: 1 female, holotype (NHM.2004.47), CP214, East Coast of Taiwan, N/ O 'Fishery Researcher 1' TAIWAN 2003, 24º28.59'N 122º12.66'E to 24º25.66'N 122º12.78'E, 490 to 1027 m; 27/08/2003, coll. T­Y Chan.

Description: relatively large Pycnogonum , trunk length (anterior of cephalon to posterior of fourth lateral processes) 4.5 mm, leg span approximately 20 mm. Integument surface densely ornamented with small wart­like papillae, each papilla with minute tubercles or occasional setae over surface ( Fig. 4 B); pale straw­coloured in life grading to pale grey on tarsi. Trunk ( Figure 4 A, C) fully segmented, tapering from anterior to posterior, lateral processes short. Dorsal trunk­midline tubercles present: tall pointed tubercles mounted on raised posterior rim of first to third trunk segments; smaller, rounded tubercles on anterior of fourth trunk segment, and centrally on cephalon. Cephalon hexagonal, 40% of trunk length, domed ocular tubercle about 1.5 times as high as wide, bearing four eyes coloured red in life; second and third trunk segments each half as long as cephalon, second 0.77 times as wide as trunk length; fourth trunk segment slightly longer than third; dorsodistal tubercles present on all lateral processes, additional posterodistal lateral process tubercles present on first and second trunk segments. Abdomen truncate, naked, not articulating, held horizontal, wider distally, reaching back as far as distal edge of coxa 2 of fourth legs.

Proboscis naked, strongly tapering, without tubercles or papillae, 1.3 times as long as cephalon; oral glands (sensu Staples 2002) not seen. Oviger absent.

Third leg ( Figure 4 D) mainly without conspicuous swellings or tubercles. Coxae subequal, wider than long; femur longest article, 2.25 times as long as wide, with midventral swelling bearing short spine; tibia 1 0.85 times as long as femur, twice as long as wide, with one midventral spine; tibia 2 0.85 times as long as tibia 1, without spines but with ventrodistal tuft of fine setae; tarsus short, quadrangular, with fine ventral setae; propodus slender, curved, with ventral fine setae mainly in a single row, and occasional small lateral spines; main claw 0.4 times length of propodus; auxiliary claws absent. Ventral setae on tibia 2, tarsus and propodus not bifurcate.

Female gonopore conspicuous on posterodorsal surface of coxa 2 of fourth legs (arrowed on Fig. 4 A). Coxal glands (sensu Staples 2002) not seen.

Measurements (mm): trunk length 4.51; width across second lateral processes 3.49; proboscis length 2.42; abdomen length 1.52; third leg, coxa 1 0.68, coxa 2 0.78, coxa 3 0.68, femur 2.03, tibia 1 1.75, tibia 2 1.46, tarsus 0.23, propodus 1.38, claw 0.26.

Etymology: from the Greek kranaos —rugged, rocky, and byrsa —hide or skin, referring to the complex pustulation of the integument of the present species (female, noun in apposition).

Remarks: There is a number of Pycnogonum species with a slender tapering proboscis, no auxiliary claws and pointed mid­dorsal trunk tubercles, but only the present species has the pustulate integument together with a rounded ocular tubercle. Using the key to the genus of Stock (1966), P. cranaobyrsa identifies to couplet 20, where both P. t o r re s i Clark, 1963 and P. indicum Sundara Raj, 1930 are distinct from the present species in having a distally rounded abdomen and blunt (distally rounded) trunk tubercles. P. i n d i c u m is further distinguished owing to its compact leg articles, both femur and tibia 1 being less than twice as long as wide ( Sundara Raj 1930). P. cranaobyrsa bears more similarity to P. o c c a Loman, 1908, but the latter species has a distally pointed ocular tubercle and more slender leg articles ( Staples 2002). Of other similar species described since Stock's (1966) review of the genus, P. eltanin Fry & Hedgpeth, 1969 is different from the present species in having distally rounded trunk tubercles; P. (N) moniliferum Stock, 1991 does have distally pointed trunk tubercles (see Bamber in press), but differs from P. cranaobyrsa in having a distally pointed ocular tubercle, a dorsal tubercle on coxa 3, and numerous spines and setae on the leg articles.

Figures

FIGURE 4. Pycnogonum cranaobyrsa sp. nov., female holotype, A, body, dorsal; B, profile of trunk papilla; C, body, lateral outline, integumental papillae not shown; D, third left leg. Scale line = 2 mm for A, C and D.