Crotonia tasmaniana, Colloff, Matthew J., 2009

Colloff, Matthew J., 2009, New species of Crotonia (Acari: Oribatida) from Tasmania Rainforest, and the habitat preferences of Crotoniidae, Zootaxa 2027, pp. 43-54 : 45-47

Crotonia tasmaniana sp. nov.

( Fig. 1 )

Crotonia dicella Colloff, 1990 : sensu Łochyńska, 2008b.

Dimensions: holotype female body length 1356, breadth 569; paratype females (n = 17): mean length 1397 (range 1306–1600); mean breadth 626 (range 528–678); paratype males (n = 8) mean length 1226 (range 1190–1254); mean breadth 525 (range 498–550); mean ratio of length of prodorsum to total length: 0.33 (both sexes).

Prodorsum: rostrum with very prominent naso; rostral setae straight, smooth ( Fig. 1 a). Lamellar setae recurved, smooth. Lamellar apophyses as long as their mutual distance; extending anteriorly beyond apices of rostral setae. Interlamellar apophyses twice as long as broad; interlamellar setae slender, flagelliform, smooth; extending anteriorly well beyond apices of rostral setae. Prodorsal ridges extending more than half the distance between interlamellar and lamellar apophyses; strongly-developed posterior inter-bothridial ridge present, with sparse fovelolae; cuticle posterior of ridge smooth. Median alveolar field present. Prodorsal microsculpture microporose.

Notogaster: ratio of length to breadth 1.5; broadest at level of seta e 2 ( Fig. 1 a). Dorsosejugal suture complex, diffuse, with pre-notogastral shield separated from notogastral shield by transverse hyaline strip on which tubercles of setae c 1 and c 2 are positioned. With 14 pairs of notogastral setae, all smooth. Notogastral shield discrete, with lateral porose margins extending just posterior to setae f 2; central field between setae d 2 also porose, extending posteriorly as far as gla, surrounded by dense tuberculate region, contiguous posteriorly. Setae c 3 flagelliform, extending as far as bothridium, on apophyses slightly shorter but thicker than those of setae in. Setae c 2 and c 1 on tubercles, c 2 almost three times longer than c 1. Distance between tubercles c 3 and c 2, c 2 and c 1and both c 1 116, 41 and 48, respectively. Lateral hyaline strip (suprapleural scissure) well developed, bearing tubercles of setae cp, e 2 and f 2. Setae cp longest of the notogastral setae, then e 2; d 2 short, setiform, on alveloli. Tubercles of setae f 2 prominent, projecting beyond lateral margin, shorter than e 2; opisthosomal gland opening gla positioned at level slightly anterior of f 2. Apophyses of spiniform setae f 1 slightly separated from those of h 1, projecting anteriorlaterally; those of h 1 projecting posteriolaterally. Setae h 2 85, spinose; their apophyses long, parallel for most of their length, diverging apically; caudal margin between them transverse, apophyses of setae h 3 positioned ventral and posterior of h 1 when viewed dorsally. Apophyses of setae f 1, h 1 and h 3 ca. 25–30, subequal.

Ve n t e r: epimeral microsculpture punctate, strongly tuberculate marginally and in perigenital region ( Fig. 1 b); epimeral setae smooth, spiniform, formula 3-2-3-3; seta 4a longer than others, 3c on well-developed tubercle. Circumgenital foramen and genital plates sub-circular. Each genital plate 202 long, 115 broad with eight spiniform setae. Anal plate 65 broad, 350 long. Setae of p series well-developed, p 2 and p 3 smooth, on short tubercles, subequal; p 1 longer, with spinose ornamentation, on short apophyses, positioned close together ( Fig. 1 b).

Material examined: holotype female from Mt. Michael. Paratypes: 12 males, 23 females, 37 adults (gender not determined), 17 immatures from Mt. Michael; 29 adults, 103 immatures from Mt. Victoria.

Etymology. This species is named for the State of Tasmania.

Remarks. This species was mis-identified by Łochyńska (2008b) as Crotonia dicella , a species described by Colloff (1990) from South Africa. Crotonia dicella differs from C. tasmaniana sp. nov. as follows: 1) it possesses very large conical apophyses of setae c 3, larger than those of setae in; 2) the apophyses of h 2 are longer, closer together and more strongly reflexed medially; 3) most of the lateral and caudal notogastral setae have spinose microsculpture; 4) setae d 2 are represented only by vestigial punctations, not setae; 5) the dorsosejugal suture is simple, discrete, with no pre-notogastral shield, not diffuse, with the tubercles of c 1 and c 2 positioned on a transverse hyaline strip; 6) the notogastral microsculpture is porose, not tuberculate; 7) apophyses of setae h 3 are positioned ventrally, between f 1 and h 1 in dorsal view, not posterior to h 1; 8) a cluster of birefringent punctations is present in the caudal region; 9) setae c 2 are almost as long as c 3, not markedly shorter; 10) a median prodorsal alveolar field is absent; 11) the interlamellar and lamellar setae have extensive flecking of cerotegument; 12) the rostral setae are curved and have spinose ornamentation.

C. tasmaniana sp. nov. can be differentiated from other members of the genus by the following combination of characters: 1) the epimeral setal formula; 2) the relative lengths of setae of the c series; 3) the tuberculate notogastral microsculpture with a central porose region; 4) apophyses of setae h 2 more or less parallel, diverging apically, with the transverse notogastral margin between them. It shares with C. ardala and C. pauropelor the differential lengths of the c series: setae c 3 longest, then c 2, c 1 shortest. The epimeral setal formula is the same (3-2-3-3) for C. ecphyla and C. tasmaniana sp. nov., but the former species has short, subequal setae c 1 and c 2, with setae c 3 on very large apophyses, very short prodorsal ridges, punctate notogastral microsculpture, and no apparent trans-bothridial ridge.

Crotonia tasmaniana sp. nov. appears to be a member of the Cophinaria species group sensu Luxton 1982. However, since that publication, several species with characteristics of the Cophinaria group have been described, or redescribed, that have the full complement of setae in the c series. These include C. alluaudi ( Berlese, 1916) as redescribed by Olszanowski (1996), C. ardala Luxton, 1987 , C. borbora Luxton, 1987 , C. capistrata Luxton, 1987 , C. dicella, Colloff, 1990 , C. ecphyla Colloff, 1990 , C. pauropelor Colloff, 1990 , C. rothschildi ( Berlese, 1916) , as redescribed by Mahunka (1991); C. tasmaniana sp. nov. and C. tryjanowskii Olszanowski, 2000 . All these species show either African or Australian distributions.

The other members of the Cophinaria group are C. brachyrostrum Hammer, 1966 , C. cophinaria ( Michael, 1908) , as redescribed by Wallwork (1977) and Luxton (1982), C. jethuremerae Lee, 1985 and C. lyrata Colloff, 1990 ; the first two species are known from New Zealand, while the latter two are from Australia and South Africa. The species with the full complement of c setae probably do not merit a separate species group at present because the polarity of this character state is not yet known. Incidentally, the synonymy of C. brachyrostrum with C. cophinaria by Luxton (1982) is questionable. The decision was not based on an examination of the types, and the differences can not simply be attributed to variation. For example C. cophinaria has very large epimeral setae 3d on long apophyses (illustrated by both Hammer 1966 and Luxton 1982). C. brachyrostrum appears to lack setae 3d altogether.

Figures

FIGURE 1. Crotonia tasmaniana sp. nov. Female a) dorsal; b) ventral