Pterozetes lawrencei, 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 : 69-70

Pterozetes lawrencei sp. nov.

( Fig. 35 )

Dimensions. Holotype female length 838 μm breadth 677 μm. Paratype female lengths 808 μm, 830 μm; breadths 667 μm, 656 μm. Ratio of prodorsum to total length: 0.41 (holotype).

Description of adult. Prodorsum: rostrum acute, apex almost covered by lamellae; rostral setae (ro) curved, thin, smooth, not visible in dorsal aspect ( Fig. 35b ). Lamellae narrow, fused anteriorly in midline, concave anterior margin bearing reticulate microsculpture and two sharply-pointed lateral apices, lateral margins almost straight, parallel ( Fig. 35a ). Lamellar setae short, thin, smooth, on anterior margin. Median area of lighter cuticle and two long, thin lighter oval regions lateral of median area. Interlamellar setae absent. Bothridia rounded projections, fused with lamellae. Bothridial seta long, thin, smooth, pointed.

Notogaster: ratio of length to breadth: 0.75; notogaster U-shaped, convex. Humeral processes long, extending as far as apex of tutorium, very broad at level of dorsosejugal scissure, with slight notch just anterior of seta la, anterior section broad, curved apically, with short, blunt terminal tooth and striated and reticulate microsculpture ( Fig. 35a ). Lyrifissures ia not visible. With nine pairs of thin, short, smooth, setiform setae positioned marginally, l and h series sub-equal in length, p series shorter than others, not visible in dorsal aspect.

Ventral aspect: subcapitulum acute, elongate, covered by tectum basally; subcapitular setae h slightly longer than a and m. Chelicerae chelate-dentate, of normal proportions. Tutorium very broad, apex blunt. Epimeral plates I very broad, trapezoid, lateral margins diffuse, broadly separated in midline; plates II and III very narrow, plates IV lacking posterior margin and setae; epimeral setation 3-1-3-2; setae very short, sub-equal in length ( Fig. 35b ). Pedotectum I (pd I) well-developed, sub-rectangular in ventral outline, with short, blunt apex; pd II rectangular in outline with medial indentation; discidium curved, sub-rectangular with posterior tooth; perigenital carina absent, posterior tubercle of enantiophysis E4 present. Ventral plate ovoid, markedly broader than long. Genital and anal plates separated by distance same as length of genital plates; genital plates 84 µm long, with five pairs of short, curved setae, g 1 positioned markedly posterior of anterior margin; setae aligned longitudinally; three pairs of extremely short adanal setae; lyrifissure iad in para-anal position, some distance from margin of anal plate, more than length of iad. Anal plates rectangular, 145 µm long. Pre-anal organ (po) oval with cylindrical apex.

Etymology. This species is named in honour of its co-collector, Dr John F. Lawrence, my former colleague and curator of Coleoptera at the Australian National Insect Collection, Canberra.

Type designation, material examined and locality data. Holotype female, ANIC accession no. 53-1055, ANIC 592 , leaf litter and decaying log, Cement Creek, 5 km west of Warburton , Victoria, 37°3’3S 145°42’E, coll. J. Lawrence and T. Weir, 18.i.1977 . Paratypes: two females, ANIC accession no. 53-1056 & 1057, ANIC 297 , Moss and litter, Nothofagus cunninghami rainforest, Cumberland Creek Valley, nr. Picnic Area [Cumberland Memorial Scenic Reserve], Yarra Ranges National Park , Victoria. 37°34’S 145°52’E, 920 m ., coll. R. W. Taylor and R. J. Bartell, 4.xi.1970 .

Diagnosis. Pterozetes lawrencei has the following distinctive character states: (1) the median area of lighter prodorsal cuticle and two long, thin lighter oval regions lateral of the median area; (2) the absence of interlamellar setae; (3) the apically curved humeral processes with a short terminal tooth and striated and reticulate microsculpture; (4) the broad tutorium with blunt apices; (5) the broad, trapezoid epimeral plates I; (6) the very narrow epimeral plates II and III; (7) the rectangular discidium with a posterior tooth; (8) five pairs of genital setae with the first pair well posterior of the anterior margin of the genital plate; (9) the oval pre-anal organ with a cylindrical apex.

Remarks. The humeral processes of P. lawrencei are different from those of P. novazealandicus which are broad basally with a triangular extension that is folded ventrally ( Hammer, 1966, Plate XXXV, Fig. 106a). However, both species have extensive reticulate and striate microsculpture on the humeral processes. The anterior margins of the lamellae of P. lawrencei are much more strongly concave, the lateral teeth are more prominent and the species has five pairs of genital setae rather than six. The internal margins of the anterior parts of the humeral processes of P. novazealandicus are concave and the apex is sharply pointed, not convex with a terminal tooth as in P. lawrencei . Hammer did not illustrate the full complement of notogastral, epimeral and anal setae or the lateral margins of the coxisternum in P. novazealandicus because the specimen she examined was heavily sclerotised, so it cannot be confirmed whether P. novazealandicus shares character states related to these structures without re-examination of the type material.

Figures

FIGURE 35. Pterozetes lawrencei sp. nov., adult, (a) dorsal aspect; (b) ventral aspect. Scale bar = 200 μm.