Crotonia cornuta, Colloff, Matthew J. & Perdomo, Giselle, 2009

Colloff, Matthew J. & Perdomo, Giselle, 2009, New species of Crotonia (Acari: Oribatida: Camisiidae) from Nothofagus and Eucalyptus forests in Victoria, Australia, with a redescription of the fossil species Crotonia ramus (Womersley, 1957), Zootaxa 2217, pp. 1-36 : 5-7

publication ID	https://doi.org/ 10.5281/zenodo.189961
DOI	https://doi.org/10.5281/zenodo.6225392
persistent identifier	https://treatment.plazi.org/id/03FEC052-FFF3-DC7A-569F-5CECFC6E0CF0
treatment provided by	Plazi
scientific name	Crotonia cornuta
status	sp. nov.

Treatment

Crotonia cornuta View in CoL sp. nov.

(Figs. 2, 15, 17–19)

Dimensions. Holotype female length 1040, breadth 525. Female paratypes (n = 4) mean length 1074, (range 1067–1082); mean breadth 534 (range 521–553). Female paratype lengths 910, 916, 1091; breadths 411, 427, 442. Mean ratio of length of prodorsum to total length: 0.33.

Female. Prodorsum: rostrum well-developed, with very prominent naso, lateral edges incurved; rostral setae (ro) 41, straight, spiniform, smooth (Fig. 2a). Lamellar setae (le) 205, recurved, smooth. Lamellar apophyses 102, two thirds as long as their mutual distance; extending just posterior of apices of rostral setae. Interlamellar apophyses twice as long as broad; interlamellar setae (in) slender, 270, flagelliform, smooth; extending anteriorly just beyond interlamellar apophyses. Prodorsal ridges extending two thirds of the distance between interlamellar and lamellar apophyses. Diameter of each bothridium 44; auriculate bothridial ridge in the form of simple D-shaped projection; bothridial membrane reticulate, with broad, well-defined, tripartite, parallel divisions between elongated cells ( Fig. 18 View FIGURE 18 e). Inter-bothridial ridge in the form of a shallow crenellated curve. Median field of muscle sigilla present. Prodorsum porose.

Subcapitulum: with three setae on gena. Oral setae or 1 bifurcate, flat, barbed unilaterally; or 2 spiniform, sparsely barbed, 20; or 3 slightly longer than or 2 ( Fig. 15 View FIGURE 15 f).

Notogaster: ratio of length to breadth 1.38; broadest at bases of setae e 2 (Fig. 2a). Dorsosejugal suture discrete, simple. With 14 pairs of smooth notogastral setae. Pre-notogastral shield separated from notogastral shield by transverse hyaline strip and bearing thin setiform setae c 2, 112, and shorter c 1, 67. Apophyses of setae c 3 prominent, 34, at least twice as long as broad; setae c 3 flagelliform, 280, extending just posterior of apices of prodorsal ridges. Notogastral shield discrete, porose; bordered laterally by two narrow strips of small tubercles extending posteriorly almost as far as setae f 1, ca. 2–3 tubercles wide, with porose cuticle laterally and medially. Caudal region with sparse tubercles, extending onto lateral notogastral plates. Lateral hyaline strip (suprapleural scissure) well developed, bearing tubercles of setae cp e 2 and f 2. Tubercles of setae f 2 on sub-triangular projections extending beyond lateral margin. Setae cp setiform, 140; d 2 setiform, 75; e 2 setiform, 104. Opisthosomal gland opening gla positioned at level slightly anterior of f 2. Smooth, flagelliform setae f 1 80, their apophyses projecting posteriolaterally and clearly separated from those of h 1. Setae h 2 75, flagelliform, smooth; their apophyses slightly longer, 134, than distance between them, parallel for most of their length, diverging apically; caudal margin between them transverse. Apophyses of setae f 1 and h 1 30–35, cylindrical, subequal; those of h 3 15, squat.

Ven ter: epimeres porose (Fig. 2b); Epimeral plates I with sharp, horn-like projections posteriolaterally; epimeral plates II with well-defined median borders. Epimeral setae smooth, spiniform, formula 3-1-3-3; setae 4a and 2b longer than others, 3c with cerotegument, on well-developed tubercle. Genital plates subcircular anterior of setae ag 2; with straight diagonal and transverse margins posterior of setae ag 2. Each plate 197 long, 112 broad with eight spiniform setae and a strongly-developed median carina. Two pairs of aggenital setae subequal in length to genital setae. Genital plates of some specimens with faintly-defined, lighter, transverse strip of cuticle. Perigenital region tuberculate. Anal plate 48 broad, 230 long, striate, with three spiniform setae in central region. Three pairs of spiniform adanal setae. Ventral margin of notogaster surrounding anal plates U-shaped with pronounced posteriomedian notch. Setae of p series smooth, setiform; p 3 60, setiform; p 2 110, setiform; p 1 105. Tubercles of setae p 1 on short projecting ridge; same distance apart as their length (Fig. 2b).

Lateral view: Caudal margin almost perpendicular to notogastral shield ( Fig. 17 View FIGURE 17 e); distance between dorsal and ventral surface ca. 360. Apophyses of setae f 1 and h 1 and h 2 pointing dorsolaterally, those of h 2 prominent, horizontal, pointing posteriorly; those of h 3 positioned on ventral surface of apophyses of setae h 3, posterior of those of h 1, pointing posterioventrally. Apophyses of setae p 1 positioned on caudal region; the most dorsally of the p series, then p 2, then p 3. Distance between apophyses of p 1 and h 3 230. Pleuraspis with few, scattered tubercles in dorsal half.

Male. As for female, except 0.9 of the length and 0.8 of the breadth.

Material Examined and Locality Data. Holotype female, one paratype female, two paratype males, litter, in riparian zone, coastal Angophora and Eucalyptus forest, Quarry Beach, Mallacoota, 149°44'2"E, 37°35'18"S, 20 m, coll. J. Bloszyk & S. Konwerski, 3.viii.2007 (CRO-006). Two paratype females, litter from tree fern (CRO-010): same locality data as CRO-006. One paratype male, litter from sedges, coastal Angophora and Eucalyptus forest, near picnic site, Sou-West Arm, Mallacoota, Croajingolong National Park. 149°41'31"E, 37°30'28"S, 30 m, coll. J. Bloszyk & S. Konwerski, 3.viii.2007 (CRO-017). Holotype, paratype female and two paratype males (CRO-006) deposited in Department of Entomology, Museum Victoria, Melbourne. Remaining paratypes in Australian National Insect Collection, CSIRO Entomology, Canberra.

Other material: Five nymphs, CRO-006; one nymph, CRO-017; one nymph, CRO-013: same data as CRO-017. One female, one male, one nymph sieved rotten wood, Eucalyptus forest, 4 km SE of Toolangi State Forest, Victoria, 37°32'39"S 145°31'38"E, 820 m, coll. D. Black, 15.i.1990. One male, one nymph, litter, Mount Donna Buang, Yarra Ranges National Park, Victoria, 37°42’S 145°41’E, 1235 m., coll. R.W. Taylor & R.J. Bartell, 5.ix.1970 ( ANIC Berlesate no. 299). One female, moss and litter, rainforest with Nothofagus cunninghami, Cumberland Creek Valley , nr. Cumberland Memorial Picnic Area [Cumberland Scenic Reserve], Yarra Ranges National Park, Victoria. 37°34’S 145°52’E, 920m. Coll. R.W. Taylor & R.J. Bartell, 4.xi.1970 ( ANIC Berlesate no. 297).

Etymology. The specific name cornuta refers to the horn-like or spine-like structure on each posteriolateral margin of epimeral plates I.

Remarks. The association of the male and the female of this species is based on the shared morphology of the bothridial auriculae, the caudal setae and their apophyses, the relative dimensions of setae of the c series, d 2 and e 2 and the tuberculate notogastral shield.

Crotonia cornuta sp. nov. differs from all other Crotonia spp. by the following combination of characters: 1) epimeral plates I with sharp, horn-like projections posteriolaterally 2) with setae c 2 present; 3) setae c 3 long, extending to midway point of prodorsal ridges; 4) notogastral shield with narrow lateral strips of small tubercles, and with diffuse tuberculate microsculpture on caudal and humeral regions, otherwise porose; 5) bothridia with narrow, curved anteriolateral auriculae; 6) setae c 1 about two-thirds the length of c 2 which are between a third and half the length of c 3; 7) inter-bothridial ridge a distinctive, crenellated, shallow curve; 8) setae d 2 very long: as long as setae cp.

Crotonia cornuta . holotype female a) dorsal; b) ventral.

Crotonia cornuta sp. nov. is a member of the Capistrata species-group ( Colloff, 2009b) and is morphologically most similar to Crotonia alpina sp. nov. and Crotonia victoriae sp. nov. It differs from both species by the presence of lateral corniculate extensions on epimeral shields I; stout, elongate epimeral setae 1b, the shape of the bothridial auriculae and the confinement of tuberculate notogastral microsculpture to narrow lateral strips and the caudal region. It differs from C. alpina sp. nov. in that setae c 3 and d 2 are shorter, the lateral apophyses of setae f 1 and h 1 are spaced apart from each other; and from C. victoriae sp. nov. by its markedly smaller size; setae h 1 and h 2 are flagellate (rather than spinose); setae d 2 and cp are longer; and setae p 1 are shorter and positioned more dorsally on the caudal margin.