Go to National Library of New Zealand Te Puna Mātauranga o Aotearoa
Volume 70, 1940-41
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Genus Isotomina Börner, 1906.

General facies of Proisotoma type, but with Abd. V and Abd. VI fused. Two species of this genus occur in New Zealand and both are endemic.

Key to the New Zealand Species of Isotomina.
1. Six large and two small ocelli to each side. Mucro with single terminal upturned tooth. I. nova-zealandia sp. nov.
2. Eight large equal ocelli to each side. Mucro with apical tooth and broad recurved sub-apical tooth. I. lamellata sp. nov.

Isotomina nova-zealandia sp. nov. Plate 53, fig. 224.

Colour: In life, blue-black; mounted, a deep brilliant blue, often tinged with violet, especially around abdomen; sometimes deep black-blue. Appendages generally a shade lighter in colour than body. Specimens from the North Island in general are lighter in colour and larger than those from the South Island.

Clothing: Of simple setae.

Body: Length up to 1·5 mm. Antennae about half as long again as head, the four segments related as 20: 30: 22: 51. Ocelli on dark fields, eight to each side, the posterior inner two very small, remainder all large and equal. Postantennal organ oval, equal to or smaller than an ocellus, never larger. Prothorax only partly covered by mesothoracic terga. Abd. IV slightly longer than Abd. III as 65: 58. Ventral tube short.

Legs: Claw with single inner tooth about two-thirds down, no outer teeth. Empodial appendage not quite as long as half the claw and with a broad outer lamella reaching to apex and a broad semi-circular inner lamella reaching about half-way. Two clavate tenent hairs longer than claw to each foot.

Furcula: Short, not reaching ventral tube. Manubrium to dens to mucro as 35: 16: 9. Dens with four long ventral setae arranged in two pairs, and one short dorsal seta at junction with mucro. Mucro long and tapering with single terminal upturned tooth.

Localities: Paiahia, North Auckland, under the bark of manuka trees and amongst leaf debris under tree-ferns; Lake Mapourika, under the bark of kahikatea trees.

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Type: Slide 3/567 and Figured Paratype: Slide 3/568, Dominion Museum Collection.

Isotomina lamellata sp. nov. Plate 53, figs. 221–223.

Colour: In life, a deep blue-black. Mounted specimens deep violet-blue on body, with pale intersegmental bands, antennae darker bluish-violet, especially distal half of Ant. IV. Ocelli on deep blue fields. Legs and furcula pale blue.

Clothing: Rather sparsely clothed with short, simple setae and some longer ones around tip of abdomen.

Body: Length 1·9 mm. Antennae slightly longer than head, the four segments related as 14: 20: 16: 35. Ocelli eight to each side and all large. Postantennal organ very large, elliptical, and at least as long as two ocelli. Abd. III to Abd. IV as 35: 41.

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Legs: Claw very broad at base, and tapering to fine point with single inner tooth about half-way down. No outer teeth. Empodial appendage about half as long as claw, with very broad, almost semi-circular inner lamella reaching half-way from base; and a medium outer lamella reaching to tip. Two clavate tenent hairs as long as claw to each foot.

Furcula: Not reaching to ventral tube. Mucro long and tapering, slightly over half as long as dens, with an apical tooth and a broad recurved sub-apical tooth. Dens with three prominent ventral setae. Dens not annulated or corrugated.

Localities: Akatarawa Divide, 1,400 ft. altitude, in rotten logs; Fish River Gorge, Haast Pass, under rimu bark; Lake Brunner, in bush soil and debris; Maruia Valley, under bark of fuchsia trees; Buller Gorge, near Westport, in old logs; Waiho Gorge, South Westland, under bark of Olearia illicifolia; Lake Wakatipu, under stones, north end of lake.

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Type: Slide 3/576, Dominion Museum Collection.