Hedgpethia shalei, Staples, 2019

Staples, David A., 2019, Pycnogonids (Arthropoda, Pycnogonida) from the Southwest Indian Ridge, Zootaxa 4567 (3), pp. 401-449 : 433-435

Hedgpethia shalei sp. nov.

Figure 16 A–G; Plate 5G, H

Material examined. Holotype, sex undetermined ( NHMUK 2018.41 ), Southwest Indian Ocean , Middle of What Seamount, 37° 56. 38.1´S, 50° 27. 16.9´E, ROV, 1414 m, specimen JC066-3522, stn 6.7, parent 2593, 2 December 2011. Photographed in aquarium on dead coral in association with yellow and orange Parazoanthids.

Paratype. One specimen ( NHMUK 2018.42 ), Southwest Indian Ocean, Coral Seamount, 41˚ 22.31'S, 42˚ 54.57'E, ROV, 732 m, specimen JC066-873, stn 4.38, parent 1272, mooring site, on net containing Mango wood packages, 20 November 2011 .

Other material. One specimen (NHMUK 2018.43), Southwest Indian Ocean, Coral Seamount, 41˚ 22.31'S, 42˚ 54.57'E, ROV, 732 m, specimen JC066-1298D, parent 1272, stn 4.38, mooring site, on net containing whale bone, 20 November 2011. One specimen ( NHMUK 2018.44 ), Southwest Indian Ocean, Coral Seamount, 41° 21.46 'S, 42˚ 54.54 'E, 687 m, specimen JC066-3109, stn 4, parent 2542, 20 November 2011 .

Description. Holotype. Leg span about 15 mm. Trunk ( Fig.16A, B . Plate 5G, H ) slender, segmented, posterior margin of each segment raised to form a low cowl; lateral processes slightly constricted in mid-region, widest distally, separated by about their own basal width. Ocular tubercle placed on mid-region of cephalon, tall, evenly tapered from base, acuminate, over-reaching base of proboscis; four large eyes of equal size near tubercle base, pigmented.

Proboscis bulbous ( Fig. 16E ), narrowest proximally, expanding evenly to reach maximum width in midregion, slight constriction at about three-quarters length, gently curved downwards, rounded at tip.

Abdomen articulated at base, very short, implanted between fourth lateral processes, barely visible dorsally, in lateral view seen extending ventrally beneath the trunk.

Palp ( Fig.16D ) ten-segmented, segment 3 longest, about 1.8 times longer than next longest segment 5, segments 6 to10 with long, fine, ventral setae.

Chelifores absent.

Oviger ( Fig.16F ) ten-segmented, segment 4 longest, claw leaf-like shape ( Fig. 16G ), spines on segments 7 to10 are in several rows but the number of rows and detail of the distal margin of the spines are unclear but appear to be spatulate shaped and smooth.

Third leg ( Fig.16C ) slender, femur gently curved, widest in mid-region, femur and tibiae with single, prominent, dorsodistal seta about twice segment width, dorsal surfaces more setose generally, tibia 1 longest, femur longer than tibia 2, tarsus slightly more than half length of propodus, 15 to 20 sole spines, spines undifferentiated, terminal claw about one-third length of propodus, auxiliary claws absent. Cement glands and gonopores not evident.

Measurements of holotype (mm). Trunk length (frontal margin of cephalic segment to tip of 4 th lateral process), 1.584; length cephalon, 0.624; width across 2 nd lateral processes, 0.888; proboscis length (dorsal), 1.232; greatest diameter proboscis, 0.600. Third leg: coxa 1, 0.200; coxa 2, 0.240; coxa 3, 0.160; femur, 1.808; tibia 1, 2.192; tibia 2, 1.544; tarsus, 0.328; propodus, 0.600; claw, 0.200. Palp: seg. 1, 0.104; seg. 2, 0.064; seg. 3, 1.264; seg. 4, 0.168; seg. 5, 0.712; seg. 6, 0.104; seg. 7, 0.224; seg. 8, 0.184; seg. 9, 0.184; seg. 10, 0.176. Oviger; seg. 2, 0.160; seg. 3, 0.136; seg. 4, 0.880; seg. 5, 0.208; seg. 6, 0.832; seg. 7, 0.344; seg 8, 0.264; seg. 9, 0.224; seg.10, 0.240; claw, 0.088.

Etymology. The specific name acknowledges the contribution made by Dr. David Shale, expedition and natural history photographer for his outstanding work capturing images of the voyage collections fauna.

Remarks. This species is most closely related to H. filamentus but is noticeably more robust. Further points of difference are in the more rounded proboscis with the basal part being shorter and less defined, the dorsoposterior margins of trunk segments 1 to 3 raised into low cowls and the lateral processes being closer together.

Figures

PLATE 5. Colossendeis sp. A, proboscis lateral; B, palp. Colossendeis melancholicus. C, specimen on rock wall. D, specimen with proboscis inserted into Isactinernus quadrilobatus. Hedgpethia filamentus sp. nov., holotype. E, trunk, lateral view; F, trunk, dorsal view. Hedgpethia shalei sp. nov., holotype. G, trunk, lateral view; H, trunk, dorsal view.

FIGURE 16. Hedgpethia shalei sp. nov., holotype. A, trunk, lateral view; B, trunk, dorsal view; C, third leg; D, left palp; E, proboscis, anterior view; F, oviger; G, oviger terminal claw.