Crotonia seemani, Colloff, Matthew J., 2010

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 : 37-38

Crotonia seemani sp. nov.

( Figs. 14 , 18 n, 21)

Dimensions: holotype female length 1272, breadth 529. Paratype females length 1303, 1296, breadth 585, 553. Paratype male length 1264, breadth 470. Ratio of length of prodorsum to total body length: 0.34 (holotype).

Description of female. Prodorsum: ratio of length to breadth 1.03. Rostrum with squat naso, barely projecting beyond rostrum; lateral edges concave; rostral seta 35, straight, spiniform, smooth ( Fig. 14 a). Lamellar seta 248, recurved, smooth. Lamellar apophyses 104, curved, narrow, about two thirds as long as their mutual distance; extending anteriorly as far as apices of rostral setae. Interlamellar apophyses cylindrical (22 long, 11 broad); interlamellar seta 363, flagelliform, smooth; extending anteriorly as far as apex of curve of lamellar setae. Prodorsal ridges absent. Diameter of each bothridium 54; auriculate ridge of bothridium a blunt, sub-rectangular projection, longer than broad, bearing a series of ramifying ridges; hexagonal reticulations of operculum with point of origin near lateral margin; with parallel and concentric ridges ( Fig. 18 n). Inter-bothridial ridge and median field of muscle sigilla not apparent Prodorsal microsculpture smooth, porose.

Notogaster: ratio of length of notogaster to breadth of notogastral shield 1.63; notogastral shield broadest at level of bases of setae e 2 ( Fig. 14 a); ratio of width of shield to entire notogastral width 0.84; margins of shield between c 3 and e 2 more-or-less straight, and between e 2 and the caudal apophyses; sub-hexagonal.

Dorsosejugal suture well-defined, with single discrete ridge slightly indented medially. Lyrifissure ia short (23) positioned in concavity lateral of seta c 3. Posterior of concavity, a short, narrow ridge extends onto cuticle dorsal of acetabulum III. With 13 pairs of smooth notogastral setae (c 2 absent).Transverse hyaline strip barely evident. Long flagelliform setae c 1 (282) and c 3 (173) on short, squat tubercles; c 3 extending anteriorly to point mid-way between interlamellar and lamellar apophyses. Notogastral shield with diffuse lateral strips of small tubercles extending anteriorly along transverse margin and broadening in caudal region. Lateral hyaline strip (suprapleural scissure) narrow, ventral of main body of dorsal notogastral plate. Setae cp, e 2 and f 2 short, stout, spiniform (ca. 25) on small tubercles. Seta d 2 thin, 28, setiform; mutual distance (100) slightly less than that between setae c 1. Straight, spiniform seta f 2 (80) on prominent conical tubercle. Opisthosomal gland opening gla positioned medial of setae f 2. Caudal apophyses bi-lobed, originating directly from caudal margin; no caudal stalk present. Apophyses of h 2 very long (184) expanded basally, slightly inflexed, medially, then diverging apically; caudal margin between them an inverted U-shape. Apophysis of h 1 (30) emerging dorsolaterally from base of that of h 2; apophysis of f 1 (35) projecting dorsolaterally, slightly separated from, and anterior of, that of h 1. Apophysis of seta h 3 positioned ventral of h 1. Setae f 1 and h 1 smooth, short, recurved, flagelliform apically, subequal in length (58–63) seta h 2 straight, spiniform, 60.

Ve nt er: epimeral microsculpture smooth, porose ( Fig. 14 b); epimeral setae smooth, spiniform, formula 3- 1-3-3; 25–35 long; 3c on well-developed tubercle. With lcs broad, straight, sloping diagonally, forming obtuse angle (ca. 130°) with pcs. Anteriolateral margin of adanal plate with narrow, shallow indentation. Genital plates sub-circular; posterior margin straight, transverse. Perigenital region smooth. Each plate 185 long, 110 broad, with eight setiform setae, subequal in length (20–30); two pairs of aggenital setae, subequal in length to genital setae. Anal plate narrow (63 broad), 323 long, with three short (17) thick setae on posterior region of plate; adanal setae ad 2-3 setiform, ad 1 spiniform (52). Margin of notogaster surrounding anal plates V-shaped. Setae of p series setiform, subequal in length (28–38), mutual distance between tubercles of p 1 about the same as width of tubercle. Tubercles of setae h 3 broad, sub-conical, on posteriolateral margins of bases of apophyses of setae h 2.

Lateral view: Caudal margin perpendicular to notogastral shield ( Fig. 14 c). Dorsal and ventral surfaces more or less parallel, distance between them perpendicular of seta f 2 425. Caudal apophyses at level slightly lower than that of notogastral shield. Apophysis of seta f 1 pointing anteriodorsally, h 1 posteriodorsally; those of h 2 four times the length of h 1, curved, horizontal, pointing posteriorly; those of h 3 positioned on caudal margin ventral of h 2, pointing posterioventrally. Apophysis of seta p 1 on caudal region, slightly less than a third of the distance between ventral and dorsal surfaces; p 2 positioned at junction between caudal margin and ventral surface; distances between p series subequal. Pleuraspis with scattered tubercles in dorsal half.

Material examined. Holotype female and paratype female, QM S26046 , moss on trees and rocks, Sky Window Lookout, Eungella National Park, Queensland, 21°10'S 148°31'E, 771 m., rainforest, coll. G.B. Monteith, 18 Apr 1979. Paratype female and paratype male, QM S26047 , moss on trees and rocks, rainforest, summit of Mount Macartney, Queensland, 20°50'S 148°33'E, 855 m., coll. G.B. Monteith, 21.iv.1979. Holotype and paratypes deposited in the Queensland Museum, Brisbane.

Etymology. Crotonia seemani is named in honour of Dr Owen Seeman (Queensland Museum), in recognition of his contribution to Australian acarology.

Remarks. Crotonia seemani differs from all other Crotonia spp. by the following combination of characters: 1) prodorsal ridges absent; 2) immensely elongated, narrow, sub-hexagonal notogastral shield; 3) thin, curved lamellar apophyses; 4)setae of c series long, flagelliform, with c 1 longer than c 3; 5) trans bothridial ridge absent; 6) notogastral shield bordered laterally, anteriorly and caudally by a broad zone of tubercles; 7) anal setae very short, confined to posterior region of plate; 8) lateral ridge of bothridium blunt, sub-rectangular, with a series of branching ridges; 9) setae cp, e 2 and f 2 short, subequal, stout, spiniform.

Although Crotonia seemani is a member of the Cophinaria species-group, like C. queenslandiae , it is not morphologically particularly similar to any other member of the group, or to any other species of Crotonia either.

Figures

FIGURE 14. Crotonia seemani sp. nov. 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.