Howickia mercurialis Marshall

Marshall, S. A., Luk, S. P. L. & Dong, H., 2014, A revision of the New Zealand species of Howickia Richards, Zootaxa 3887 (1), pp. 1-36: 15

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Howickia mercurialis Marshall

sp. nov.

Howickia mercurialis Marshall   sp. nov.

( Figs. 5, 6 View FIGURES 1 – 8 , 34–38 View FIGURES 34 – 39 )

Description. Colour: Face bare and shining at middle only, upper and lower margins white pruinose; gena mostly bare with vibrissal angle and upper margin white pruinose. Legs mostly brown with orange knees; first tarsomere of fore and mid leg reddish brown, other tarsomeres pale brown to white.

Head: Upper orbital bristle minute, outer vertical similarly reduced. Ocelli small but distinct. Arista with hairs 1.5X as long as width of first aristomere.

Thorax: Scutum shining, without microtrichia except for narrow anterior and posterior fringes. Postalar and dorsocentral twice as long as scutellar bristles. Scutellum 4 X as wide as long, bare and shining except for microtrichose margin. Wing present as a short, oval, transluscent flap with a single loop of venation. Portion of wing beyond loop of venation less than half as large as portion enclosed by vein.

Abdomen: Tergites 1–3 fused into a large syntergite covering most of the abdomen.

Male abdomen: Synsternite 2 + 3 large, longer than sternites 4–5 combined. Sternite 5 short, subequal to sternite 4, slightly paler medially and with medial area flanked by small setae; sternite 4 unmodified. Subanal plate complete, narrow; lower/outer part of cercus broadly rounded. Surstylus with stout posteroventral spur and quadrate anteroventral process, ventral surface otherwise smooth. Hypandrium broadly but asymmetrically fused with anteroventral corners of epandrium, fused area of right side shorter and twice as wide as fused area on left. Ventral lobe of hypandrium prominent, U-shaped. Posterodorsal apodeme of hypandrium strongly developed, reaching anterior surface of distiphallus near base. Distiphallus relatively broad and short, with a broad spinulose apex. Postgonites narrow, slightly broader basally and bent anteriorly at right angles near middle, distal part parallel-sided. Basiphallus frame-like, projecting posteriorly but deflexed ventrally and distally almost parallel to distiphallus base.

Female abdomen: As described for H. bicolor   , but cerci and epiproct greatly reduced and apparently fused into a small, bare sclerite.

Type material. ( NZAC, all point-mounted): Holotype male (debu00127423) and 16 paratypes (10 males, 6 females): New Zealand, Mercury Islands, Green Island, pitfall trap under Coprosma   , 11–23.Dec. 1987, G. Hall. An additional 3 males and 7 females have the same data except "under Melicytus ramiflorus   ". Other paratypes: Mercury Islands, Middle Island, litter 83 / 110, 20.Oct. 1983, Island Southey (30 males, 9 females); same data but collected from litter 83 / 111 (17 males, 13 females); Cuvier Island, Old Radar Station, pitfall trap, 25.Feb – 2.Mar. 1982, G. Hall (2 males, 1 female, see notes below); Ohena Islands, ex. litter, 26.Nov. 1972, G.W. Ramsay (1 female, NZAC).

Other material examined (in alcohol, not designated as paratypes; in addition to several further vials from the Mercury Islands): Ohena Islands, Keruenga Island, 27.Nov. 1972, G.W. Ramsay (4 specimens, NZAC).

Etymology. Howickia mercurialis   is named for the type locality.

Comments. Howickia mercurialis   is closely related to H. omamari   , with which it shares several unequivocal synapomorphies including the capsule-like abdomen dominated by a hugely expanded syntergite 1–3. These species have distinctly different surstyli and can be easily separated by the relative pruinosity of the scutum (bare and shining in H. mercurialis   , microtrichose and dull in H. omamari   ).

All specimens are from the Mercury Islands except the three specimens from Cuvier Island, about 15 km north of Mercury Island. Those three specimens have a more reddish thorax than any of the specimens from the Mercury Islands, but they seem identical in male genitalic features.


New Zealand Arthropod Collection