Tumerozetidae Hammer 1966

Redefinition of Tumerozetidae

Definition. Relatively small, sub-globose non-poronotic brachypyline oribatid mites with the hysterosoma moreor-less as broad as long; with modified plate-like extensions of humeral, notogastral and/or prodorsal region forming convex coverings of the prodorsal surface. Subcapitulum secondarily anarthric with genal tectum divided by medial infrabuccal cleft; labiogenal articulation absent; bases of setae a and h positioned on tectum rather than covered by it. Rutellum bifurcate; chelicerae modified, with digitus fixus bearing lobe-like scale apically; digitus mobilis with comb-like fringe. Prodorsum with well-developed lamellae with cusps. Humeral processes well-developed; either relatively short and projecting anteriomedially or massive, covering lateral prodorsum between dorsosejugal furrow and bothridia. Tutorium and pedotectum I present; pedotectum II present or absent. Well-developed discidium present. Notogaster with 9-11 pairs of marginal setae. With well-developed circumpedal carinae. Epimeral plates discrete, separated in mid-line. Genital setae 4-5 pairs; aggenital setae 1 pair, anal setae 2 pairs, adanal setae 2 pairs; monodactylous.

Remarks. The redefinition of the family is required to accommodate Sacculella gen. nov., defined below. Hitherto, the definition of Tumerozetidae was based on that for Tumerozetes by Hammer (1966), as modified by Luxton (1985). Hammer did not define the family, stating only “ Tumerozetes does not belong to any family known so far but forms its own family, the Tumerozetidae.” Family definitions were given by Piffl (1972) and Woas (2002). Piffl (1972) defined the family as Polypterozetoidea with medial notogastral sculpture extending over the dorsosejugal boundary, without scalps, with 10 pairs of notogastral and 6 or 5 pairs of genital setae, and only 2 pairs of adanal setae.

Woas (2002) defined the Tumerozetidae as follows: “Prodorsum with swollen, plate-like, interlamellar projections dorsal of well-developed lamellae; digitus fixus of chelicera separated from main cheliceral body by distinct step, with hook-like tooth ks (shared with Polypterozetidae). Cuticle with extremely well-developed cerotegument (shared with Polypterozetes, Gymnodamaeoidea and most of the ancient Eupheredermata) covering larger parts of prodorsum; rostral region bill-shaped, distinctly incurved, ending bluntly and turned down sharply at its distal end; tutoria developed; central portion of notogaster with two longitudinal dorsal carinae; humeral region of notogaster with shoulder pieces (reminiscent of Polypterozetes); notogaster encircled by a line of setae (resembling immatures of Polypterozetes), in some species the setae bifurcate; in ventral aspect, acetabular region with smaller triangular processes in place of pedotecta II (shared with Polypterozetidae); epimeral region with four pairs of distinct epimera (shared with Polypterozetidae); genital opening flanked by distinct aggenital ridges (reminiscent of Carabodes); preanal organ tubular-claviform, almost reaching rear border of genital opening (shared with Megeremaeidae); anal opening wider posteriorly than anteriorly and at most as long as genital opening; ventral plate with carina circumpedalis, dorsal branch qp in front of dorsosejugal line of notogaster; bases of rutella fused with mentum, Y-shaped tips distinctly separated from mentum (shared with Polypterozetidae); genu of leg I abruptly calyx-like, broadened distally.”

There are some issues with this definition. Woas (2002) confused the well-developed interlamellar plates (bearing the interlamellar setae) with the lamellae, though they are clearly different and separate when viewed in lateral orientation (Figure 1c). The description of the chelicera with hook-like tooth ks, as in Polypterozetes cherubin (Figure 4j) does not accord with the morphology of the chelicera of Tumerozetes roughleyi sp. nov. (Figure 2d), the only species in the Tumerozetidae for which the chelicera has been described. The cerotegumental covering is unique in that it consists of ovoid-rectangular lumps of a dark, possibly waxy, secretion (Hammer 1966, p. 81 stated “thick solid strings of wax are attached to the lamellar plates, to the lateral sides of the hysterosoma, etc.”), but the cerotegument is not necessarily extensive and in T. roughleyi sp. nov. it tends to be mostly confined to the anterior part of the rostrum. The small triangular process referred to ‘in place of pedotecta II’, and found in Polypterozetes, is the patronium, positioned between pedotecta I and II. This structure is clearly illustrated for Tumerozetes bifurcatus Hammer, 1966 by Norton and Behan-Pelletier (2009, Fig. 15.51F therein), is present in T. roughleyi sp. nov. (Figures 1b, 1c) and probably all other Tumerozetes spp. described by Hammer (1966), though it was not illustrated or mentioned in her descriptions. Finally, the preanal organ is claviform and reaching the posterior margin of the genital plate in T. bifurcatus (Hammer 1966, Figure 110a therein) but in T. roughleyi sp. nov. it is broad, T-shaped and does not extend as far as the genital plate (Figure 2g).