Crotonia ardala Luxton, 1987

Colloff, Matthew J., 2010, The Gondwanan relict oribatid genus Crotonia (Acari: Oribatida: Crotoniidae) from rainforests in Queensland and Northern New South Wales: new species show a mixed pattern of short-range and long-range endemism, Zootaxa 2649, pp. 1-51 : 17-20

Crotonia ardala Luxton, 1987

( Figs. 6 , 18 f, 21)

Dimensions: syntypes: female lengths 932, 1088; breadths 458, 460. Male length 830, breadth 380. Ratio of length of prodorsum to total body length: 0.3 (female specimen labelled ‘holotype’).

Redescription of female. Prodorsum: ratio of length to breadth 1.04. Rostrum with squat naso, barely projecting beyond rostrum; lateral edges parallel; rostral seta 20, straight, spiniform, smooth ( Fig. 6 a). Lamellar seta 123, recurved, barbed, flagelliform apically. Lamellar apophyses short (42), straight, thin, parallel, close together, positioned just posterior of naso, same length as their mutual distance, extending anteriorly as far as apices of rostral setae. Interlamellar apophyses short, thin, as long as broad; interlamellar seta 207, flagelliform, smooth; extending anteriorly beyond apex of curve of lamellar setae. Prodorsal ridges curved medially, with lateral plaques, extending anteriorly over half the distance between bases of interlamellar and lamellar apophyses. Diameter of bothridium 38; auriculate ridge of bothridium in the form of a pair of sub-triangular projections; hexagonal reticulations of operculum lacking concentric ridges and with point of origin near lateral margin ( Fig. 18 f). Inter-bothridial ridge a shallow, indented, well-defined curve without a median invagination. Median field of muscle sigilla present. Prodorsal microsculpture smooth, porose with region of cuticular plaques lateral of prodorsal ridges.

Notogaster: ratio of length of notogaster to breadth of notogastral shield 1.5; notogastral shield broadest at level of bases of setae e 2 ( Fig. 6 a); ratio of width of shield to entire notogastral width 0.84; lateral margins of notogastral shield convex, oval, inflated. Dorsosejugal suture a single discrete ridge. Region lateral of apophyses of setae c 3 very slightly concave, waisted. Lyrifissure ia short (45 long) located immediately posterior of concave region. With 14 pairs of smooth notogastral setae. Pre-notogastral shield separated from notogastral shield by broad transverse hyaline strip, and bearing long flagelliform seta c 3 (247) emerging from short (15) apophyses, extending anteriorly as far as bases of lamellar apophyses. Long, thin, flagelliform seta c 2 (148) and shorter setiform seta c 1 emerging from small tubercles on posterior margin of pre-notogastral shield. Notogastral shield smooth, slightly convex, tapering to U-shape anterior of caudal apophyses; caudal region with elongated crenellated margins; shield bordered laterally by broad strips of small rhomboid plaques. Lateral hyaline strip (suprapleural scissure) wide, bearing tubercles of setae cp e 2 and f 2. Seta d 2 long (80) thin, setiform; mutual distance (133) the same as that between setae c 2. Seta cp long, setiform, e 2 slightly shorter, f 2 shorter (52), curved, on tubercle but not projecting from margin of notogastral shield. Opisthosomal gland opening gla positioned medial of setae f 2. Caudal apophyses on very short broad stalk, projecting posteriorly from caudal margin. Caudal apophyses clustered; those of h 2 longer than others (74), inflexed apically. Apophysis of h 1 (32) emerging dorsolaterally from bases of that of h 2; that of f 1 (45) curving dorsolaterally. Seta f 1 and h 1 short, subequal (32), covered in bacilliform cerotegument. Seta h 2 50, spiniform. Seta h 3 positioned anteriorly and ventrally of h 1, just visible dorsally.

Ve nt e r: epimeral microsculpture smooth, porose (Fig. 10b); most ventral setae with bacilliform cerotegument; epimeral setae smooth, spiniform, subequal, formula 3-1-3-3; ca. 10–20 long; seta 3c on welldeveloped tubercle. With lcs broad, curved, forming an obtuse angle (ca. 130°) with pcs. Anteriolateral margin of adanal plate with a narrow, shallow indentation. Genital plates sub-circular; posterior margin transverse. Perigenital region densely tuberculate. Each genital plate 138 long, 84 broad, with eight setiform setae, subequal in length (15); two pairs of aggenital setae, subequal in length to genital setae. Anal plate narrow (35 broad), 190 long, with three short (25) setae on central region of plate; three pairs of spiniform adanal setae, ad 2-3 slightly shorter and thinner than spiniform stout ad 1 (37). Ventral margin of notogaster surrounding anal plates acutely V-shaped. Setae p 2 and p 3 setiform, subequal in length (32), p 1 flagelliform apically, 59, tubercles of p 1 almost adjacent.

Lateral view: Caudal margin perpendicular to notogastral shield ( Fig. 6 c); dorsal and ventral surfaces convex, not parallel, distance between them ca. 396. Apophysis of seta f 1 pointing dorsally, those of h 1 posteriodorsally, those of h 2 twice the length of h 1, more-or-less horizontal, pointing posteriorly; those of h 3 positioned ventral of h 1, pointing ventrolaterally. Caudal cluster positioned at same level as notogastral shield. Apophysis of seta p 1 almost at junction of caudal margin and ventral surface; p series equidistantly spaced. Pleuraspis with dorsal series of small rhomboid plaques.

Material examined. Syntypes: female (labelled ‘holotype’), QM S40735 , moss on trees and rocks, rainforest, Summit TV Station, Bellenden Ker Range, Queensland, 17°16' S 14551'E, 1560 m., coll. Earthwatch/QLD. Museum, 1–7.xi.1981. Female (Labelled ‘paratype’) QM S40774 , moss on tree trunks, rainforest, Summit TV Station, Bellenden Ker Range, Queensland, 17°16'S 145°51'E, 1560 m., coll. 25– 31.x.1981. Male (labelled ‘paratype’), QM S40732 , moss on tree trunks, rainforest, Summit TV Station, Bellenden Ker Range, Queensland, 17°16'S 145°51'E, 1560 m., coll. Earthwatch/QLD. Museum, 25– 31.x.1981 (QM Berlesate No. 370).

Non-type material: Seven males, seven females, moss, ANIC 367, forest, summit of Mount Bellenden Ker, Queensland, 17°16’S 145°51’E, ca. 1560 m., coll. R.W. Taylor and J.E. Feehan, 7.vii.1971.

Remarks. As for Crotonia borbora and C. capistrata, Luxton (1987) did not publish a holotype designation for C. ardala (cf. remarks section of C. borbora ) so all the material mentioned by him constitutes a syntype series. The specimen from sample QM S40735 is labelled ‘holotype’ and this is hereby designated the lectotype. All other members of Luxton’s series therefore become paralectotypes.

Luxton’s (1987) depiction of the caudal apophyses of Crotonia ardala is slightly different from that herein (his Figs. 3 and 5 B differ from each other). The apophyses are closer to those shown in Luxton’s Fig. 5 B, but h 2 are shorter and more curved medially. Also, the caudal setae are not barbed: setae h 2 are recurved and setiform, not spiniform, and setae f 1 and h 1 have bacilliform cerotegument.

Crotonia ardala differs from all from all other Crotonia spp. by the following combination of characters: 1) the lamellar apophyses are relatively close together and short; barely further apart than width of naso, and only just extending beyond it; 2) long flagelliform setae c 3 (though barely extending as far as lamellar apophyses), slightly shorter setae c 2, subequal in length to setae d 2, and setae c 1 shorter still; 3) setae cp long, extending almost as far as bases of setae e 2; 4) notogastral shield with lateral strips of small rhomboid plaques; these also present on pleuraspis; 5) apophyses of setae h 2 relatively short, only about twice as long as those of h 1, their apices strongly curved medially; 6) auriculate ridge of bothridium with a pair of large, blunt lateral projections; 7) barbed lamellar setae.

Crotonia ardala is morphologically similar to C. maculata in the relative lengths and mutual distances of setae of the c series, as well as the well-developed setae d 2. But C. ardala has much shorter apophyses of setae h 3 and rhomboid plaques rather than sub-circular maculae on the notogastral shield.

Łochyńska (2008b) recorded C. ardala from Queensland, New South Wales and Victoria. The doubtful validity of records from Victoria was discussed by Colloff & Perdomo 2009), based on the highly localised distribution of C. ardala , confined to rainforest in northern Queensland. The specimens on which these records were based were recently returned to the Australian National Insect Collection and determined as follows. ANIC 367 (Mt. Bellenden Ker, Queensland): C. ardala , 23 females, 24 males, five nymphs. ANIC 450 (Miala National Park, nr. Mt. Glorious, Queensland; labelled ANIC 0 45 by Łochyńska [2008b]): C. maculata , one female. ANIC 469 (Clyde Mountain, southern New South Wales): C. sp. near victoriae Colloff & Perdomo, 2009 , one female, three males, five nymphs. ANIC 770 (Wiangaree State Forest, northern New South Wales): C. daviesae , two females. ANIC 772 (Wiangaree State Forest): C. daviesae , two females; C. brisbanensis , one female; Crotonia sp. near capistrata , one female, four males. Material from ANIC 297 (Cumberland Scenic Reserve, Victoria) was not available for study. These identifications confirm that Crotonia ardala has a localised distribution, confined to the Mount Bellenden Ker region, North Queensland.

Figures

FIGURE 3. Crotonia brisbanensis sp. nov. holotype female a) dorsal; b) ventral; c) posteriolateral.

FIGURE 5. Crotonia capistrata Luxton, 1987 holotype female a) dorsal; b) ventral; c) posteriolateral.

FIGURE 6. Crotonia ardala Luxton, 1987 holotype female a) dorsal; b) ventral; c) lateral.

FIGURE 18. Details of bothridia of a) Crotonia sterigma sp. nov.; b) Crotonia borbora Luxton, 1987; c) Crotonia brisbanensis sp. nov.; d) Crotonia maculata sp. nov.; e) Crotonia capistrata Luxton, 1987; f) Crotonia ardala Luxton, 1987; g) Crotonia monteithi sp. nov.; h) Crotonia daviesae sp. nov.; i) Crotonia weiri sp. nov.; j) Crotonia yeatesi sp. nov.; k) Crotonia cameroni sp. nov.; l) Crotonia eungella sp. nov. m) Crotonia queenslandiae sp. nov.; n) Crotonia seemani sp. nov.; o) Crotonia raveni sp. nov.