A new genus of oribatid mite, Spineremaeus gen. nov. and three new species of Scapheremaeus (Acari: Oribatida: Cymbaeremaeidae) from Norfolk Island, South-west Pacific, and their biogeographical affinities Author Colloff, Matthew J. text Zootaxa 2011 2828 19 37 journal article 10.5281/zenodo.206955 c2b78e7e-e0ad-42c5-8334-facb1f08c146 1175-5326 206955 Spineremaeus gen. nov. Diagnosis. Cymbaeremaeidae with the following combination of characters: interbothridial ridge entire bearing prominent interlamellar setae emerging from well-developed apophyses with protuberant apical rims. With ten pairs of notogastral setae; lm and lp and lyrifissurae im in central position on notogaster, on lateral margins of an elongate, irregular, sub-rectangular notogastral ridge. Circumdorsal scissure absent. Lenticulus large, bulbous, protuberant; notogaster with centrodorsal region strongly domed and lateral region flat. Type species: Spineremaeus smithi sp. nov. Remarks. Spineremaeus is closest morphologically to Scapheremaeus Berlese, 1910 . The new genus is established based on the presence of the prominent, broad interlamellar setae emerging from well-developed rimmed apophyses on an entire interbothridial ridge. The well-developed, thick, barbed interlamellar setae represent a synapomorphic character within the Cymbaeremaeidae , shared with Bulleremaeus from New Zealand ( Hammer, 1966 ). The prominent, rimmed apophyses of the interlamellar setae are considered autapomorphic within the Oribatida . The crenellated, sub-rectangular centrodorsal ridge might conceivably represent the vestige of a circumdorsal scissure, and is an autapomorphy within the Oribatida . Setae lm and lp and lyrifissurae im have migrated from lateral positions, as found in most species of Scapheremaeus , to centrodorsal positions along the margins of the circumdorsal ridge. The interpretation that the centrodorsal setae are lm and lp , rather than dm and dp , is based partly on lyrifissurae im co-located in the centrodorsal position, but also that Scapheremaeus spp. belonging to the Humeratus species-group ( Colloff, 2009 ), for example Sc. hungarorum Mahunka 1986 (cf. also Mahunka, 2010 ), show a tendency for setae lm and lp to be positioned towards the centrodorsal region, though not lyrifissurae im . Scapheremaeus emarginatus Hammer, 1966 also has setae lm and lp positioned centrodorsally. Spineremaeus shares the absence of a circumdorsal scissure with two of the non-plicate species-groups of Scapheremaeus , as well as with all other genera within the Cymbaeremaeidae . The members of the Humeratus species-group have the circumdorsal scissure reduced to its anterior portion only, with the posterior portion fused. In the Emarginatus group the circumdorsal scissure is absent altogether ( Colloff, 2009 ). Members of the Emarginatus group are found in Australia , Java, New Zealand , and a somewhat anomalous member, Sc. morenoi ( Balogh & Mahunka, 1974 ) is from Cuba ( Colloff, 2010a ). Scapheremaeus pinguis sp. nov. described herein from Norfolk Island (cf. below) is also a member of the Emarginatus group.