Eutegaeus woiwurrung, 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 : 15-18

Eutegaeus woiwurrung sp. nov.

( Figs. 2–4 )

Dimensions. Holotype female: length 1,062 μm, breadth 858 μm. Paratype males (n = 4): mean length 976 μm (range 960–985 μm); mean breadth 774 μm (range 742–815 μm). Paratype females (n = 9): mean length 1,009 μm (range 983–1,036 μm); mean breadth 805 μm (range 750–819 μm). Ratio of prodorsum to total length: 0.38 (holotype). Paratype tritonymphs (n = 6): mean length 859 μm (range 823–908 μm); mean breadth 651 μm (range 602–719 μm).

Description of adult. Prodorsum: rostrum acute; rostral setae (ro) curved, well-developed, with spinose ornamentation, visible in dorsal view. Lamellae broad, separated medially, parallel; with partial translamella at base of lamellar cusps; lamellar setae (le) smooth, curved, extending well beyond apices of rostral setae, emerging from cup-shaped incisions, each seta flanked by two sharp teeth of equal size; cusps extending anteriorly just beyond rostrum ( Fig. 2a ). Interlamellar seta (in) about same length as seta le. Bothridia projecting laterally beyond margin of prodorsum, with anterior condyle of enantiophysis H in form of V-shaped posterior flange. Bothridial seta long, curved, bacilliform, smooth.

Notogaster: thin membranous cerotegument covering parts of notogaster; ratio of length to breadth: 0.78; notogaster rounded, convex. Humeral processes relatively narrow, with dorsal keel, slightly waisted basally, then expanded and pointed apically, extending to point level with middle of lamella ( Fig. 2a ). Short, sharp lateral projection bearing lyrifissure ia on notogaster posterolateral of humeral process. With eight pairs of notogastral setae, l series, h 2 and h 3 present, relatively long, curved, with fine spines along convex aspect; setae la and lm in sub-marginal position, lp, h 2 and h 3 and p series marginal ( Fig. 2c ); setae of p series very short, curved, smooth. Lyrifissures im present lateral of setae lm.

Ventral aspect: subcapitulum acute apically; mentum as long as broad; subcapitular setae short, smooth, sub-equal in length. Tutorium relatively short, apex blunt. Epimeral plates discrete, all broadly separated in midline, plates I sub-triangular to rectangular, others sub-rectangular, plates II shorter than others. Epimeral setation 3-1-4-2; setae 1b, 3b, 3d and 4c at least twice as long as others ( Fig. 2b ). Pedotectum I (pd I) well-developed, sub-rectangular; pd II small, pointed; discidium with sharp point. Ventral plate broader than long. Genital and anal plates separated by distance about same as length of genital plates; genital plates 115 µm long, with six pairs of setae, g 5 displaced laterally; lyrifissure iad in para-anal position, some distance from margin of anal plate, same as seta ad 3. Anal plates lozenge-shaped, 214 µm long. Pre-anal organ (po) broad, flat T-shaped.

Description of tritonymph, nymphal and larval scalps. Tritonymph prodorsum: rostrum acute; rostral setae with fine spines, on short tubercles; lamellar setae with spinose ornamentation, emerging from shallow depression on lamellar cusp; median apex of cusp with long, sharp tooth ( Fig. 3a ). Lamellae strongly incised laterally just posterior of setae le and again anterior of bothridia, with blocky, alveolate microsculpture. Lateral margin of prodorsum alveolate, posteromedian region smooth, porose; setae in minute. Bothridia with broad flanges posteriorly and anteriorly ( Fig. 3b ). Bothridial seta long, slim, expanded apically, with sharp tip.

Tritonymph gastronotum: U-shaped, broader (657 µm) than long (617 µm). Gastronotal setae emerging from elongate, cup-shaped or hemi-semicircular overlapping scales, each with pointed tip anteriorly and posteriorly and ornamented with fine, vein-like pattern from medial setal insertion canal ( Fig. 3a ). With 11 pairs of setae (c 1 absent): c 2 on short tubercles posterior of bothridium, smooth, setiform; setae c 3, the l and h series and p 1 straight, ornamented with fine spines; scale of seta h 1 smaller than those of other h and l series; setae p 1 on single rectangular scale; setae p 2 and p 3 minute, positioned ventrally. Cuticle alveolate between setal scales and with cerotegument of blunt spines.

Deutonymphal scalp: with eight pairs of setae: c 1 and c 3, l series and h 2, h 3 and p 1; scale of seta h 1 present but seta absent; setae p 1 without scale but on long apophyses ( Fig. 3a ).

Protonymphal scalp: with seven pairs of setae: c 3, l series, h 2, h 3 and p 1; p 1 on short tubercles ( Fig. 3a ).

Larval scalp: with alveolate microsculpture; scales absent, seven pairs of setae on short tubercles: l series, h 3 and centrodorsal d series. Setae dp on ovoid sclerite ( Fig. 3a ).

Deutonymph ventral aspect: epimeral setal formula 3-1-2-2; with three pairs of genital setae, one pair of aggenital setae, three pairs of adanal setae; anal setae absent ( Fig. 4b ).

Tritonymph ventral aspect: epimeral setal formula 3-1-3-3; with five pairs of genital setae, one pair of aggenital setae, two pairs of anal setae and three pairs of adanal setae ( Fig. 4a ).

Ontogenetic formula of gastronotic setae (including one larval and two protonymphal and deutonymphal setae not present on scalps): 8-(9,10,11)-8.

Type designation, material examined and locality data. Holotype female, ANIC accession no. 53-1027; paratypes: six females, five males, eight nymphs, ANIC accession nos. 53-1028 & 1029, ANIC 297 , Moss and litter, Nothofagus cunninghami rainforest, Cumberland Creek Valley, near 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 . Paratype: female, ANIC accession no. 53-1030, Cumberland Creek Valley nr. Cambarville [Marysville-Woods Point Road], Yarra Ranges National Park , Victoria, 37º33’S 145º53’E, coll. R. E. Roughley, 12.iii.1996 . Paratypes: two females, one tritonymph, ANIC accession no. 53-1031, moss, Nothofagus cunninghami rainforest, rainforest walk, Maits Rest, Great Otway National Park , Victoria, 38°45’S, 143°33’E, coll. M.J. Colloff, 19.vii.2011 . Paratype female, ANIC accession no. 53-1032, TAS-012, pyrethrum knock-down, Nothofagus cunninghamii rainforest, Site 3, Pipeline Road, Savage River , Tasmania, 41º30'S 145º20'E, coll. J. Diggle, 20.iv.1989 .

Etymology. The specific name is a noun in apposition. The species is named for the Woiwurrung People of the Yarra Valley and the Victorian Great Dividing Range on whose traditional land this species was found.

Diagnosis. Eutegaeus woiwurrung can be distinguished from other species in the genus by the following combination of characters: (1) the barbed rostral setae; (2) the presence of a projection posterior of the humeral process; (3) the epimeral setal formula 3-1-4-2; (4) some epimeral setae are twice as long as others; (5) lyrifissure iad is some distance from the margin of the anal plate; about the same as that of ad 3; (6) the lamellar seta emerges from a deep, cup-shaped incision of the lamellar cusp and is flanked by two sharp teeth of equal length; (7) the posterior margin of the bothridium bears the anterior condyle of enantiophysis H.

Remarks. The other Eutegaeus spp. that have a sharp lateral projection posterior of the humeral process are E. nothofagi sp. nov., E. bidhawal sp. nov., E. odontatus sp. nov., E. curviseta and E. membraniger , the latter two from New Zealand. E. nothofagi sp. nov. is morphologically most similar to E. woiwurrung . The former species also has the epimeral setal formula 3-1-4-2 (also found in E. papuensis from Papua New Guinea) and a V-shaped bothridial flange. However, E. nothofagi sp. nov. is much larger, has small teeth on the lamellar cusp with a shallow incision and has condyles on the prodorsum.

The association of the immatures with the adult is based on their presence in the same samples and the absence of other adults of Eutegaeus spp. The tritonymphs of E. woiwurrung are 859 μm long, which accords with the mean length of the adults (females 1,062 μm, males 976 μm), whereas the tritonymphs of E. nothofagi sp. nov. are longer than the adults of E. woiwurrung (cf. below). Also, the shape and size of the large median tooth on the lamellar cusp of the tritonymph of E. woiwurrung matches that of the adult, whereas the paired teeth on the lamellar cusp of the adult E. nothofagi sp. nov. are smaller and of a different shape.

The tritonymph of this species has the epimeral setal formula 3-1-3-3, but in the adult, it is 3-1-3-2, with seta 4b absent as in E. bhidawal sp. nov., E. ptilosus sp. nov., E. odontatus sp. nov., E. similis and E. soror . Seta 4b is present in the adults of those other species of Eutegaeus for which the epimeral setal formula can be clearly determined.

Figures

FIGURE 2. Eutegaeus woiwurrung sp. nov., adult (a) dorsal aspect; (b) ventral aspect; (c) detail of left notogastral seta lm. Scale bar = 200 μm.

FIGURE 3. Eutegaeus woiwurrung sp. nov., immatures (a) tritonymph (Tn), dorsal aspect, bearing larval (La), protonymphal (Pn) and deutonymphal (Dn) scalps. Arrow indicates the scale associated with seta h1, but the seta itself is absent. Scale bar = 200 μm; (b) tritonymph, bothridium. Scale bar = 40 μm.

FIGURE 4. Eutegaeus woiwurrung sp. nov., immatures (a) tritonymph, ventral aspect. Scale bar = 150 μm; (b) deutonymph ventral aspect. Scale bar = 200 μm.