Sacculella, Colloff, 2022

Colloff, Matthew J., 2022, First records of Tumerozetidae and Nodocepheidae from Australia, with descriptions of new taxa and a re-assessment of the Polypterozetoidea (Oribatida, Brachypylina), Zootaxa 5194 (1), pp. 33-57 : 40-41

Sacculella gen. nov.

( Figures 3 , 4 )

Type species: Sacculella yarra sp. nov.

Definition. Adults. Relatively small, sub-globose, non-poronotic brachypyline oribatid mites. Rostrum covered by broad lamellae diverging posteriolaterally; with lamellar setae positioned ventrally on lamellae. Subcapitulum secondarily anarthric; apex of rutellum Y-shaped. Digitus fixus of chelicera a lobe-like structure; digitus mobilis comb-like. Rostrum truncated, anterior margin vertical in lateral view ( Figure 3a ). Bothridium well-developed, with peripheral and internal sclerotized thickening; bothridial setae elongated, setiform. Notogaster broader than long, smooth, without scalps; with 11 pairs of short, marginal notogastral setae; large, inflated, sub-trapezoid humeral processes. Humeral processes with V-shaped dorsal keels and extending as far as posterior margin of bothridia. Dorsosejugal furrow straight, transverse. Epimeral plates well-defined, sub-rectangular, separate in medial line. Pedotectum I and II, patronium and discidium well-developed. Circumpedal carina present. Genital setae 4 pairs, aggenital setae 1 pair, anal setae 2 pairs, adanal setae 2 pairs; anal plates lozenge-shaped; pre-anal organ T-shaped. Legs monodactylous, claw lacking dorsal tooth.

Diagnosis. Adults of this genus are unique among the non-poronotic Brachypylina and the Polypterozetoidea in having the following combination of character states: subcapitulum secondarily anarthric; rostrum covered by broad lamellae; rostrum truncated, vertical in lateral aspect; lamellar seta on ventral surface of lamella; with well-developed pointed discidium and circumpedal carina; notogaster broader than long, smooth, with 11 pairs of marginal notogastral setae; humeral processes large, inflated, sub-trapezoid, bearing setae c 2; 4 pairs of genital setae and 2 pairs of adanal setae.

Remarks. Sacculella gen. nov. is included in the Tumerozetidae on the basis of a set of shared character states with Tumerozetes : the secondarily anarthric subcapitulum, with a tectum derived from the genae and with a median infrabuccal cleft and the bases of setae a and h not hidden by the tectum in ventral orientation; the digitus fixus of the chelicera terminating in a lobe-like structure and the digitus mobilis with a comb-like margin; the presence of a circumpedal carina; two pairs of adanal setae; the sub-globose hysterosoma, more-or-less as broad as long; with 9 pairs of marginal notogastral setae.

Etymology. The generic prefix saccul - is derived from the Latin sacculus (a small bag or sac) and refers to the inflated humeral regions of the type species. The suffix - ella is the Latin diminutive, referring to the small size of the species.

Figures

FIGURE 3. Sacculella yarra gen. et sp. nov. (a) dorsal aspect; (b) ventral aspect; (c) lateral aspect. Scale bar = 100 μm

FIGURE 4. Sacculella yarra gen. et sp. nov. (a) palp; (b) chelicera; (c) digitus mobilis of chelicera, ventral aspect; (d) tutorium and sub-tutorium. Nodocepheus luxtoni sp. nov. (e) chelicera; (f) palp; (g) apex of rutellum; (h) tutorium and sub-tutorium; (i) rostrum and rostral setae; (j) Polypterozetes cherubin Grandjean, 1959, chelicera; (k) Podopterotegaeus miyamaensis Fujikawa, 2008, chelicera; (l) Nodocepheus dentatus Hammer, 1958, chelicera. Scale bars: a, b, d, e, f, h = 20 μm; i = 10 μm; c, g = 5 μm