Crotonia monteithi, 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 : 20-22

Crotonia monteithi sp. nov.

( Figs. 7 , 18 g, 21)

Dimensions: holotype female length 869, breadth 420. Ratio of length of prodorsum to total body length: 0.33 (holotype).

Description of female. Prodorsum: ratio of length to breadth 1.0. Rostrum with prominent naso, projecting well beyond rostrum; lateral edges parallel; rostral seta 33, straight, spiniform, smooth ( Fig. 7 a). Lamellar seta 233, recurved, barbed, flagelliform apically. Lamellar apophyses 95, straight, thin, parallel, shorter than their mutual distance by just less than a quarter; extending anteriorly beyond apices of rostral setae. Interlamellar apophyses twice as long as broad; interlamellar seta 294, flagelliform, smooth; extending anteriorly as far as apex of curve of lamellar setae. Prodorsal ridges well-developed, strongly curved medially, extending anteriorly a third of the distance between bases of interlamellar and lamellar apophyses. Diameter of bothridium 40; auriculate ridge of bothridium in the form of four or five blunt points; hexagonal reticulations of operculum lacking concentric ridges and with point of origin near lateral margin ( Fig. 18 g). Inter-bothridial ridge well-developed, straight, transverse, curved anteriolaterally at margins, with a slight median invagination. Median field of muscle sigilla not apparent. Prodorsal microsculpture smooth, porose.

Notogaster: ratio of length of notogaster to breadth of notogastral shield 1.12; notogastral shield broadest at level of bases of setae e 2 ( Fig. 7 a); ratio of width of shield to entire notogastral width 1.0; lateral margins of notogastral shield expanded, sub-circular. Dorsosejugal suture diffuse, with very faint ridge. Region posterior of apophyses of setae c 3 with a slight concavity and a small ridge bearing short (17) lyrifissure ia. With 14 pairs of smooth notogastral setae. Pre-notogastral shield not apparent. Apophysis of seta c 3 long (50), slightly curved, cylindrical, projecting anteriolaterally well beyond border of notogastral shield; seta c 3 flagelliform, 156, extending anteriorly as far as bothridia. Seta c 1 and c 2 short, thin, setiform, 33 and 47. Notogastral shield occupying entire visible dorsal surface, sub-circular, porose. Lateral hyaline strip (suprapleural scissure) very narrow. Setae cp and e 2 extremely long, curved, setiform, 320 and 295 respectively; apex of cp overlapping base of e 2, apex of extending posteriorly beyond caudal margin. Seta d 2 thin, setiform, very short (22); mutual distance (155) slightly less than that between setae c 2. Seta f 2 on small squat tubercle barely projecting from margin of notogastral shield. Opisthosomal gland opening gla positioned medial of setae f 2. Caudal apophyses originating directly from caudal margin; no caudal stalk present. Apophysis of seta h 2 consisting of a pair of very long (195), closely-spaced stalks of irregular thickness, inflexed basally, then diverging slightly. Apophysis of seta h 1 (28) emerging dorsolaterally from point of inflexion of that of h 2; apophyses of seta f 1 (30) separate from, and anterior of, that of seta h 1. Caudal margin between apophyses of setae h 2 transverse. Seta h 3 not visible in dorsal view. Caudal setae smooth, short, straight, semi-spiniform, flagelliform apically, f 1 and h 1 subequal in length (40–45), h 2 64.

Ven te r: epimeral microsculpture smooth, porose ( Fig. 7 b); epimeral setae smooth, spiniform, subequal, formula 3-1-3-3; ca. 14–22 long; seta 3c on well-developed tubercle. With lcs broad, curved, forming an obtuse angle (ca. 125°) with pcs. Anteriolateral margin of adanal plate with narrow, deep indentation. Genital plates sub-circular; posterior margin transverse. Perigenital region smooth, porose. Each genital plate 155 long, 83 broad, with eight setiform setae, subequal in length (22); two pairs of aggenital setae, subequal in length to genital setae. Anal plate narrow (42 broad), 188 long, with three short (10) setae on central region; three pairs of spiniform adanal setae, ad 2-3 shorter and thinner than spiniform stout ad 1 (25). Ventral margin of notogaster surrounding anal plates curved, U-shaped. Setae p 2 and p 3 setiform, subequal in length (22), p 1 strongly curved, 30, tubercles of p 1 almost adjacent.

Material examined. QM S26052 , sieved litter, rainforest, Cape Tribulation, Queensland, 16°05'S 145°27'E, coll. G.B. Monteith, D.K. Yeates & G. Thompson, 2.x.1982. Holotype deposited in the Queensland Museum, Brisbane.

Etymology. This species is named in honour of Dr Geoff Monteith (Queensland Museum), in recognition of his contribution to Australian entomology.

Remarks. Crotonia monteithi differs from all from all other Crotonia spp. by the following combination of characters: 1) the poorly-defined dorsosejugal suture and apparent lack of a pre-notogastral shield; 2) the extremely long apophyses of setae c3 with long, flagelliform setae extending as far as interlamellar setae; 3) with greatly elongated setae cp and e 2; 4) with very long apophyses of setae h 2, originating on the caudal margin not on a caudal stalk; 5) with barbed lamellar setae; 6) notogastral plate uniformly smooth, porose; lacking lateral strips of small tubercles.

Crotonia monteithi is morphologically most similar to Crotonia brisbanensis in the relative lengths and mutual distances of setae of the c series, the barbed lamellar setae, the poorly-defined and relatively diffuse dorsosejugal suture and the overall morphology and proportions of the caudal apophyses. They differ in that C. monteithi has setae d 2 present, lacks a caudal stalk and lateral tubercles on the notogastral shield.

Figures

FIGURE 7. Crotonia monteithi sp. nov. holotype female a) dorsal; b) ventral.

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.