Sadocepheus remus, Colloff, 2023

Colloff, Matthew J., 2023, The oribatid mite superfamily Eutegaeoidea (Acari, Oribatida), with descriptions of new taxa from Australia and New Caledonia and a re-assessment of genera and families, Zootaxa 5365 (1), pp. 1-93 : 65-67

Sadocepheus remus sp. nov.

( Fig. 34 )

Dimensions. Holotype male length 667 μm, breadth 576 μm. Paratype male length 667 μm, breadth 576 μm. Paratype females (n = 5) mean length 737 μm (range 712–793 μm), mean breadth 575 μm (range 551–602 μm). Ratio of prodorsum to total length: 0.37 (holotype).

Description of adult. Prodorsum: rostrum acute, apex not covered by lamellae; rostral setae (ro) straight, thin, visible in dorsal aspect ( Fig. 34a ). Lamellae broad, more lightly sclerotised oval region centrally and anteriorly, with reticulate cerotegument, apically with a translamella. Lamellar cusps broad, sub-rectangular, extending well beyond rostrum. Lamellar setae short, stout, recurved, smooth. Large, curved pedotectum I projecting laterally well beyond margin of prodorsum and anteriorly almost level with translamella. Interlamellar setae (in) short, straight, smooth, on median margins of lamellae anterior of faint, transverse ridge. Bothridia corniculate, fused with lamellae. Bothridial seta long, head expanded, with sparse apical spines.

Notogaster: ratio of length to breadth: 0.72; notogaster rounded, convex, with reticulate cerotegument laterally, becoming smooth in centrodorsal region. Humeral processes with short, broad anterior section, heavily notched at base, extending as far anteriorly as bothridia, lateral margin sub-rectangular, extending posteriorly to between bases of setae lm and lp, posterior part with three indented, ovoid, lighter areas of cuticle bearing sinuous microsculpture ( Fig. 34a ). Lyrifissure ia visible. With nine pairs of thin, relatively long, smooth, setiform notogastral setae, sub-equal in length; p series shorter than others, not visible in dorsal aspect.

Ventral aspect: subcapitulum acute, elongate; subcapitular setae h slightly longer than a and m. Tutorium broad, well-developed, connected with ventral surface of lamellar cusp. Epimeral plates diffuse, broadly separated in midline, sub-rectangular to trapezoid, plates I extremely large, plates III much smaller than others; epimeral setation 3-1-2-2; setae very short, sub-equal in length ( Fig. 34b ). Pedotectum I (pd I) massive, with prominent horn-shaped apex; pd II very long, paddle-shaped, with convex anterior margin; discidium lobe-like, rounded. Ventral plate ovoid, markedly broader than long. Genital and anal plates separated by distance of one third of length of genital plates; genital plates 95 µm long, with six pairs of short setae, g 1 slightly longer than others; aligned longitudinally; three pairs of very short adanal setae; lyrifissure iad in para-anal position, close to margin of anal plate, about same as length of iad. Anal plates rectangular, 122 µm long. Pre-anal organ (po) oval.

Etymology. The specific name remus is Latin for oar or paddle, referring to the long, paddle-shaped pedotectum II.

Type designation, material examined and locality data. Holotype male, ANIC accession no. 53-1084, ANIC 459 , litter, Nothofagus moorei rainforest, O’Reilly’s Rainforest Retreat, Lamington National Park , Queensland, 28°14’S 153°08’E, 920 m, coll. R. W. Taylor, 21.iii.1973 . Paratypes: one male, one female, ANIC accession no. 53-1085, ANIC 460 , litter, Nothofagus moorei rainforest O’Reilly’s Rainforest Retreat, Lamington National Park , Queensland, 28°14'S, 153°08'E, 920 m ., coll. R. J. Kohout, 21.iii.1973 . Paratype: female, ANIC accession no. 53- 1086, ANIC 655 A, litter, Nothofagus moorei rainforest, O’Reilly’s Rainforest Retreat, Lamington National Park , Queensland, 28°14'S, 153°08'E, 920 m., coll. J. Lawrence and T. Weir, 22-27.xi.1978 . Paratypes: three females, ANIC accession no. 53-1087, ANIC 838 , litter, closed forest, Dorrigo National Park , New South Wales, 30°23'S, 152°44'E, 600 m, coll. L. Hill, 14.vi.1982 . One paratype female, ANIC accession no. 53-1088, ANIC 775 , litter, closed forest, Richmond Range State Forest , New South Wales, 28°29’S 152°35’E, 600 m, coll. T. Weir and A. Calder, 13-14.ii. 1983 .

Diagnosis. Sadocepheus remus can be distinguished from other species in the genus by the following combination of characters: (1) the short, blunt lamellar cusps; (2) the recurved lamellar setae; (3) the apex of the rostrum visible in dorsal view; (4) the light areas of cuticle with wavy microsculpture on the humeral processes; (5) the prominent notch at the base of the anterior lobe of the humeral process; (6) the relatively long notogastral setae of the l and h series; (7) the prominent, wide tutorium connected with the ventral surface of lamellar cusps; (8) the massive pedotectum I with a prominent sharp spine; (9) the elongated, paddle-shaped pedotectum II with a curved anterior margin; (10) the large, lobe-shaped discidium.

Remarks. Sadocepheus remus is morphologically quite different from other members of the genus. In S. dhatiwalalensis , S. donvictorianoensis Ermilov and Corpuz-Raros, 2017 , S. dubius , S. foveolatus , S. makarcevae , S. sausai , S. serratus and S. undulatus pedotectum II is sub-rectangular. Of these species, the discidium is pointed and spine-like in S. donvictorianoensis , S. elevatus and S. sausai . In S. nortonroyi pedotectum II is sub-circular. In S. yakuensis Aoki, 2006 and S. subniger the coxisternal region has not been described but S. yakuensis has much longer notogastral setae than S. remus and S. subniger has much more strongly convergent lamellae and the humeral processes have different morphology.

Figures

FIGURE 34. Sadocepheus remus sp. nov., adult (a) dorsal aspect; (b) ventral aspect. Scale bar = 200 μm.