Eremaeozetes malleensis, Colloff, Matthew J., 2012

Colloff, Matthew J., 2012, New eremaeozetid mites (Acari: Oribatida: Eremaeozetoidea) from the south-western Pacific region and the taxonomic status of the Eremaeozetidae and Idiozetidae, Zootaxa 3435, pp. 1-39 : 10-15

Eremaeozetes malleensis sp. nov.

( Figs. 5–8 )

Dimensions. Holotype male length 558 μm, breadth 308 μm. Paratype females mean length (n = 4) 524 μm (range 488−573 μm); mean breadth 304 μm (range 284−336 μm); paratype male lengths 551, 556 μm, breadths 282, 309 μm. Ratio of prodorsum to total length: 0.28 (holotype).

Female. Cerotegument: amorphous, thin, granular, complete dorsally, sparser ventrally, covered in organic and mineral debris.

Prodorsum: Lamellae relatively narrow, not extending laterally beyond margins of bothridia, fused posteriomedially, striated on posteriolateral margins, otherwise smooth, separated along anterior third by narrow median slit with parallel margins. Lamellar cuspides slightly curved medioventrally, broadly separated apically. Posteriolateral lamellar margins transverse, incised ( Fig. 5 a). Rostral seta (ro) thin, minute (3 μm long), emerging from squat tubercle ( Fig. 5 b). Lamellar seta (le) 4 μm long, spiniform, emerging from squat tubercle on apex of lamella. Bothridial seta 59 μm long; head narrow, club-shaped, barbed. Bothridium prominent, broad, cup-shaped, rim undulating.

Notogaster: Length 421 μm; ratio of length to breadth 1.37; notogaster broad, U-shaped; broadest in region of pteromorphs. Dorsosejugal suture concave becoming acute medially; median projection entire, extending to bothridia, overhanging prodorsum ( Fig. 5 a). Dorsosejugal lobe triangular, broader than long, extending anteriorly as far as bothridium, medial margin straight. Lenticulus immediately posterior of apex of median projection of dorsosejugal suture, 41 μm long, 34 μm broad, ovoid, broadest basally, with discrete, simple margin. With faint elongate foveolae; faint, paired undulating longitudinal ridges, converging medially posterior of setae lp. Ten pairs of smooth, short (8–14 μm) spiniform setae on squat tubercles. Lyrifissure ih longitudinal, 22 μm long, positioned lateral of seta lm. Caudal region of notogaster rounded, with tubercles of h and p series projecting beyond margin.

Subcapitulum: Mentum U-shaped, as long as broad; anterior margin slightly reflexed; region immediately posterior of margin concave, smooth ( Fig. 5 b). Central region of mentum with sinuous, interdigitating ridges. Seta h 17 μm long, m 11 μm.

Coxisternum: Epimeral setae short, sub-equal (6–8 μm long), spiniform, formula 3-1-2-2 ( Fig. 5 b). Pre-genital sclerite trapezoid, with undulating margins, bearing seta 3a. Genital and anal plates separated by distance of three quarters length of genital plate. Genital plates sub-hexagonal, smooth; each plate 87 μm long, 45 μm broad, with six setae; g 1 lateral of g 2-6; g 2 longer than others; g 1 and g 3-5 with bacilliform cerotegument. Aggenital seta thin, spiniform, 6 μm long, positioned posteriolateral of genital plate. Ventral plate striate posteriolaterally, otherwise smooth.

Anogenital Region: Anal plates sub-hexagonal ( Fig. 5 b); each anal plate 66 μm long, 30 μm broad, smooth. Anal setae spiniform, 5 μm long. Adanal setae spiniform; ad 1-2 positioned on ridge immediately posterior of anal plates; distance between ad 1 and ad 2 three times mutual distance between ad 1; ad 3 positioned laterally.

Lateral aspect: Rostrum curved, acute apically, with distinct anterior projection marked by transverse ridge dorsal of insertions of rostral setae ( Fig. 5 c). Rostral seta minute, spiniform, on squat tubercle some distance from apex of rostrum. Tutorium narrow, fused apically with rostrum – without free apices. Lamellar cuspides curved anterioventrally, pointed apically, not reflexed; lamellae curved, free of prodorsum for 0.6 of entire length, with posterior septum connecting with tutorium ventrally. Lamellar setae minute, spiniform, just posterior of apex of lamellar cusp. Lamellae smooth; pedotectum I smooth, curved, lacking tooth. Interbothridial region flat. Lenticulus bulbous, curved, projecting above dorsal surface. Dorsosejugal lobe not extending as far as bothridium; pteromorph triangular, narrow, pointed, curved, smooth, extending almost as far as ventral surface, 134 μm long, 59 μm broad basally; posterior margin undulating. Centrodorsal region of notogaster flat from posterior of lenticulus to level with seta lp; posterior notogaster between lp and p 1 curved, convex.

Legs: Pretarsi heterotridactylous ( Fig. 6 ). Formulae: Leg I: 0-4-2(1)-4(2)-16(2); Leg II 0-4-3(1)-4(1)-15(2); Leg III 0-2-2(1)-4(1)-12; Leg IV 1-2 -2(1)-3(1)-11.

Tritonymph. Length 482 μm, breadth 306 μm. Prodorsum: Rostral seta (ro) straight, smooth, 21 μm long, on short cylindrical apophysis ( Fig. 7 a). Lamellar seta (le) 25 μm long, with club-shaped tuberculate cerotegument. Interlamellar seta (in) with club-shaped tuberculate cerotegument, 20 μm long. Bothridial seta (bs) 48 μm long, with club-shaped, tuberculate head. Prodorsum smooth, with complex series of longitudinal and transverse ridges.

Gastronotic Region: Length 315 μm; ratio of length to breadth 1.04; U-shaped ( Fig. 7 b). Cuticle with sparse, broadly-spaced plicate ridges. With 15 pairs of setae 25–44 μm long; all except p series with club-shaped tuberculate cerotegument; p series positioned ventrally; l series positioned along lateral margin.

Coxisternum: Epimeral plates separated along sternal line by transversely-ridged cuticle ( Fig. 7 b). Epimeral setal formula 3-0-1-1. Epimeral setae smooth, setiform, 8–14 μm long. Epimeral plates smooth.

Anogenital Region: Each genital plate 61 μm long, 15 μm broad, with six smooth, setiform setae, 7 μm long ( Fig. 7 b). Genital plates surrounded by longitudinal and transverse striate cuticle. Each anal plate 83 μm long, 14 μm broad, smooth. Setae of p series spiniform, smooth, 12–18 μm long, p 2-3 straight, p 1 curved.

Legs: Pretarsi monodactylous ( Fig. 8 ). Formulae: Leg I: 0-4-2(1)-4(2)-13(2); Leg II 0-3-3(1)-4(1)-12(2); Leg III 0-2-2(1)-3(1)-13; Leg IV 1-2 -2-3(1)-12.

Material examined. Holotype male, gutter of flight intercept trap, Mallee eucalypt woodland on dune-swale system, Bookmark Biosphere Reserve, 31 km N.W. of Renmark, South Australia, 33°59'S, 140°30'E, ca. 45 m., coll. K.R. Pullen, 30 Mar.–2 May, 1995. Paratype male and paratype tritonymph, gutter of flight intercept trap, Casuarina and Mallee eucalypt woodland, Bookmark Biosphere Reserve, 79 km N.N.W. Renmark, South Australia, 33°31'S, 140°24'E, ca. 80 m., coll. K.R. Pullen, 29 Mar.–3 May, 1995. Four paratype females and one paratype male, gutter of flight intercept trap, Mallee eucalypt woodland on dune-swale system, 14 km W.N.W. Renmark, South Australia, 34°07'S 140°37'E., ca. 30 m., coll. K.R. Pullen, 28 Feb.–28 Mar. and 6 May–7 June, 1995. Holotype and paratypes deposited in the Australian National Insect Collection, CSIRO Ecosystem Sciences, Canberra.

Etymology. This species is named for its habitation of Mallee eucalypt woodland.

Remarks. The association of the tritonymph with the adult is based on their presence in the same sample; the thin, elongate shape of the bothridial seta and the setation of the legs, with the solenidia on tibia I emerging from a long apical apophysis, with φ 2 in the dorsal position. The tritonymph has setae in and the full complement of dorsal setae (da, dm and dp), absent in the adult.

Eremaeozetes malleensis differs from other species in the genus by the following combination of characters: 1) the narrow lamellae, not extending laterally beyond the margins of the bothridia; 2) the acute dorsosejugal suture overhanging the prodorsum; 3) the ovoid lenticulus, broadest basally; 4) the faint, elongate foveolae on the notogaster; 5) the faint, paired, undulating longitudinal ridges, converging medially posterior of setae lp; 6) the apically acute rostrum in lateral view, with a distinct anterior projection; 7) the narrow pteromorph in lateral view, with an undulating posterior margin; 8) the heterotridactylous pretarsus.

Eremaeozetes malleensis is a member of the Reticulatus species group. It is morphologically most similar to E. darwinensis in that it has basically the same pattern of notogastral ridges, though they are much fainter, and it is heterotridactylous. Other species morphologically allied to the Reticulatus group but which lack well defined dorsal ridges include E. undulatus Mahunka, 1985 from St. Lucia (of unknown dactylous configuration), E. acutus Covarrubias, 1967 from Chile (which is heterotridactylous) and E. roguini Mahunka, 1998 from St. Lucia (which is monodactylous).

Figures

FIGURE 5. Eremaeozetes malleensis sp. nov., holotype female, cerotegument removed; a) dorsal; b) ventral; c) lateral aspect.

FIGURE 6. Eremaeozetes malleensis sp. nov., left legs, antiaxial view, cerotegument removed; a) Leg I; b) Leg II; c) leg III; d) Leg IV.

FIGURE 7. Eremaeozetes malleensis sp. nov., tritonymph, cerotegument removed; a) dorsal; b) ventral.

FIGURE 8. Eremaeozetes malleensis sp. nov., tritonymph, left legs, antiaxial view, cerotegument removed; a) Leg I; b) Leg II; c) leg III; d) Leg IV.