Bornebuschiidae, 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 : 67

Bornebuschiidae fam. nov.

Type genus: Bornebuschia Hammer, 1966, p. 75 .

Diagnosis. Rostrum complex, modified: with one or two incisions medially or with median ridge or tongue-like protuberance and associated lateral lobes; anterior margin transverse, not rounded. Lamellae either very long with pointed free cusps extending considerably beyond rostrum or with blunt free cusps extending just beyond rostrum; lamellar setae positioned markedly sub-apically and laterally. Bothridia free, not fused with lamellae. With well-developed condyles of enantiophyses H on posterior prodorsum and anterior notogaster; anterior condyle, or both condyles, of prodorsal enantiophysis B present, positioned medially of enantiophyses H. Humeral process short, not reaching further than bothridium, rounded apically, emerging from anterolateral margin of notogaster. Subcapitulum narrow, much longer than broad. Notogaster U-shaped; with eight ( Bornebuschia ) or nine ( Dicrotegaeus ) pairs of setae arranged in three ranks: marginal (p series); sub-marginal (h 2 and h 3), and centrodorsal (la and lm); setae of p series typically same size and shape as other notogastral setae, visible in dorsal aspect: only p 1 occasionally slightly smaller, positioned on ventral notogastral margin. Chelicerae modified: either thin with chelicerate digits but with reduced number of teeth or needle-like, with mobile digit elongated, longer than fixed digit, bearing two minute apical teeth. Perigenital carinae and/or enantiophyses E4 present, enantiophyses V on lateral margins of epimeral plates III and IV. Pedotectum I trapezoid/rectangular in ventral aspect; pd II rectangular; discidium lobed, rounded. Circumpedal carina absent. Six pairs of genital setae, penultimate pair displaced laterally; two or three pairs of adanal setae. Anal plates lozenge-shaped. Pre-anal organ T-shaped ( Bornebuschia ) or oval ( Dicrotegaeus ).

Remarks. Luxton (1988b) included Bornebuschia and Dicrotegaeus , both confined to New Zealand, within the Compactozetidae , but highlighted the modified rostrum and fine, needle-like chelicerae in Bornebuschia nodosa Luxton1988 and Dicrotegaeus mirabilis Luxton,1988 ,a synapomorphy,and quite unlike the slim, chelate chelicerae of Atalotegaeus mensarosi , though this type of modification is found in Dicrotegaeus mariehammerae Ermilov & Minor 2015 and D. incurvus Ermilov & Minor 2015 . Bornebuschia and Dicrotegaeus are unlike other Compactozetidae , as detailed above, particularly regarding the disposition of the notogastral setae in three ranks and the morphology of the lamellae, rostrum and subcapitulum and are hereby placed in the new family, Bornebuschiidae . There are several other synapomorphies for the family, including the lobed or incised rostrum; presence of enantiophyses V; setae le emerging sub-apically, at or near the base of the lamellar cusp and the arrangement of the notogastral setae in three ranks. Luxton (1988b, p. 310 and Fig. 1B ) described the subcapitulum of Bornebuschia nodosa Luxton, 1988b as ‘oval’ with 3-4 pairs of ‘hypostomal setae’ and that of Dicrotegaeus mirabilis Luxton 1988b as ‘urnlike’ (p. 311, Fig. 3B ), i.e. slim and acute, broadening basally and not arched as in other Eutegaeoidea , and with 4-5 pairs of ‘fine hypostomal setae’. These setae were not mentioned in the original description of B. peculiaris Hammer, 1966 , which did not include a diagram of the ventral aspect. Nor were they mentioned in the descriptions of D. mariehammerae Ermilov & Minor, 2015 and D. incurvus Ermilov & Minor, 2015 . If confirmed, subcapitular neotrichy would represent a further synapomorphy of Bornebuschia and Dicrotegaeus within the Eutegaeoidea . Bornebuschia and Dicrotegaeus both have the lamellar setae positioned markedly sub-apically and laterally of the apices of the lamellar cusps and are the only known genera in the Eutegaeoidea with enantiophyses V present.

Figures

FIGURE 1. Global distribution of genera and species of Eutegaeoidea and Cepheoidea, based on records of type localities of species described prior to the present work. Inset: detail of type localities of species in New Zealand.

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.