Compactozetes pirumorpha, 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 : 57-59

Compactozetes pirumorpha sp. nov.

( Fig. 29 )

Dimensions. Holotype female length 880 μm, breadth 721 μm. Paratype males (n = 4) mean length 833 μm (range 829–838 μm), mean breadth 672 μm (range 656–695 μm). Paratype females (n = 9) mean length 912 μm (range 885–928 μm), mean breadth 732 μm (range 695–758 μm). Ratio of prodorsum to total length: 0.41 (holotype).

Description of adult. Prodorsum: rostrum entirely covered by lamellae; rostral setae (ro) only visible in ventral aspect, short, smooth, curved. Lamellae very broad, with reticulate apical microsculpture, apices fused; anterior lamellar margin truncated, forming concave transverse apex with small sharp points laterally ( Fig. 29a ); lamellae curving ventrally and fused with rostrum; with large lateral foramina between lamellae and prodorsum, visible in ventral view ( Fig. 29b ) and corresponding with lighter, ovoid areas of cuticle on dorsal surfaces of lamellae. Tutorium poorly-developed with short, pointed apex. Massive, curved pedotectum I projecting laterally well beyond margin of prodorsum and as far as level of apices of tutorium. Lamellar seta (le) short, thin, smooth, curved laterally on anterolateral margin of lamella. Interlamellar setae (in) setiform, on lamellae close to median margins. Bothridia corniculate, fused with lamellae, projecting slightly beyond posterolateral lamellar margins. Bothridial seta long, head slightly expanded with few apical spines.

Notogaster: ratio of length to breadth: 0.74; notogaster rounded, convex, with reticulate cerotegument laterally. Humeral processes short, broad, anterior region sub-triangular extending to bothridia, lateral margin extending posteriorly as far as bases of setae lp, with four indented, ovoid lobes indicated by lighter areas of cuticle ( Fig. 29a ). Lyrifissures ia and im not visible. With nine pairs of short, smooth, setiform notogastral setae in marginal position, l and h series longer than p series which are visible in dorsal aspect.

Ventral aspect: subcapitulum acute, elongated; subcapitular setae h thin, longer than a and m. Margins of epimeral plates diffuse, plates broadly separated in midline, sub-rectangular to trapezoid, plates III much smaller than others; epimeral setation 3-1-2-2; epimeral setae short, 4c longer than others ( Fig. 29b ). Pedotectum I (pd I) massive, with prominent horn-shaped apex, lateral margins strongly convex with small lateral cusp; pd II rectangular, with median indentation; discidium broad with blunt apex; perigenital carina present, enantiophysis E4 absent. Ventral plate ovoid, broader than long. Genital and anal plates separated by distance of two-thirds length of genital plates; genital plates 86 µm long, with six pairs of short setae, g 1 slightly longer than others, 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 sub-rectangular, 112 µm long. With shallow, curved ridge posterior of anal plates. Pre-anal organ (po) oval.

Etymology. The specific name is derived from the Latin pirum, meaning ‘a pear’, referring to the shape of the species in dorsal view.

Type designation, material examined and locality data. Holotype female, ANIC accession no. 53-1072, paratypes: eight females, three males, ANIC accession no. 53-1073, ANIC 107 , moist upland hardwood forest (cf. Invasive Species Council and TierraMar, 2021 for description), Mount Pitt , Norfolk Island, 29°1’S, 167°56’E, 230 m, coll. M.S. Upton, 12.vii.1968 . Paratype: male, ANIC accession no. 53-1074, ANIC 1025 , litter under Araucaria heterophylla, Red Road Track , Norfolk Island National Park, Norfolk Island, 29°01'S 167°57'E, coll. T. A. Weir, 14.xi.1984 .

Diagnosis. Compactozetes pirumorpha can be distinguished from other species in the genus by the following combination of characters: (1) the very short, curved rostral setae; (2) the small sharp points on the anterolateral margin of the fused lamellae; (3) the humeral process with a sub-triangular anterior lobe and a slight indentation posterior of it; (4) the notogastral setae of the l, h and p series all short, subequal in length; (5) the very large, broad, curved pedotectum I with a pointed apex; (6) the small cusp on the lateral margin of pedotectum I; (7) the rectangular pedotectum II with a median indentation; (8) the presence of faint perigenital carinae; (9) the shallow, curved ridge posterior of the anal plates.

Remarks. Compactozetes pirumorpha belongs to the species group, ‘rotoruensis’, which includes C. duonodulus sp. nov. (cf. below) to which it is morphologically most similar, including the shape of pedotectum I and pd II; the broad, pointed discidium and the short notogastral setae, sub-equal in length. Compactozetes pirumorpha differs from C. duonodulus sp. nov. in the sharply pointed (rather than rounded, tuberculate) lateral apices of the lamellae; the absence of enantiophyses E4 and the shorter humeral processes, extending only to just posterior of the bothridia.

Figures

FIGURE 29. Compactozetes pirumorpha sp. nov., adult (a) dorsal aspect; (b) ventral aspect. Scale bar = 200 μm.