Topalia caliginosa, Colloff, 2019

Colloff, Matthew J., 2019, The oribatid mite genus Topalia in Australia (Oribatida: Nosybeidae) and the taxonomic status of related families and genera, Zootaxa 4647 (1), pp. 290-321 : 293-295

Topalia caliginosa sp. nov.

( Figs. 1–3 , 11a , 12a , 14a )

Dimensions. Holotype length 378 μm, breadth 233 μm. Paratypes: mean length (n = 11) 370 μm (range 340–394 μm); mean breadth 226 μm (range 204–236 μm). Ratio of prodorsum to total length: 0.34 (holotype).

Adult. Integument: prodorsum with sparsely-distributed tubercles. Notogaster with coarse irregular granules and tubercles overlaying fine pattern of angular foveolae. Cerotegument sparing or absent in centrodorsal region. Underlying cuticle smooth.

Prodorsum: rostrum incised, with two lateral teeth and shorter median tooth. Lamellae separated along midline, incurved apically, with narrow anterior translamella positioned ventrally. Interlamellar region with sub-semicircular ridge bearing setae in on squat tubercles. Bothridial seta short, with attenuated club-shaped apices with blunt spines.

Notogaster: ratio of length to breadth: 1.1. Anterior margin of notogaster straight, transverse, then indented posterior of bothridia. Humeral projections (h) rounded, bearing seta c 2, incurved posteriorly at level of lyrifissurae ia. Margins of centrodorsal ridge well-developed, converging anterior of setae dm, then diverging; posterior part of ridge rounded. Setae of p series visible only in ventral aspect. notogastral setae on squat tubercles.

Ventral aspect: subcapitulum narrow; with very short spiniform setae h; rutellum pointed with three minute, curved, sharp teeth. Chelicerae slim, narrow; digits with reduced number of teeth. Palp setal formula 0-2-1-2-7.

Epimeral plates I one-third broader (anterior to posterior) than long (lateral to medial); sub-rectangular to ovoid; epimera III and IV partly fused transversely and along mid-line; epimeral setation 3-1-2-2. Perigenital carina curved, ca. 35 µm long, extending posteriorly to point level with seta g 3 ( Fig. 1b ). Genital plates 40 µm long, same length as anal plates and twice length of distance between them.

Lateral aspect: apices of lamellar cusps curved ventrally and medially. Interlamellar region slightly domed. Anterior margin of rostrum between tutorium (tu) and rostral seta strongly concave, becoming vertical dorsally. Tutorium with short free cusp. Anterior margin of pedotectum I rounded, convex; apex of pedotectum II extending almost as far as level of dorsal margin of acetabulum of leg I. Centrodorsal ridge protruding to level of interlamellar region, initially concave, becoming flattened, extending posteriorly as far as level of insertion points of setae h 2; region immediately posterior slightly concave.

Legs: Tarsus I with 16 setae including short setiform famulus ( Fig. 3a ); solenidia ω 1 and ω 2 subequal in length (33 µm); tibia I with solenidion φ 1 very long (122 µm), flagelliform. Genu I bearing short solenidion σ. Femur IV with one dorsal and one ventral seta. Tarsus IV with 12 setae ( Fig. 3b ).

Material Examined and Locality Data. Holotype and 24 paratypes: ANIC 4016 , moss on Sassafras ( Atherosperma moschatum ), cool temperate rainforest, 1077 m., Errinundra Saddle, Errinundra National Park , Victoria, 37°19’S 148°51’E, coll. M.J. Colloff, 29.ix.2009.

Etymology. The specific name is derived from the Latin caligo (mist), referring to the weather conditions common at its type locality.

Diagnosis. Topalia caliginosa sp. nov. can be distinguished from all other species in the genus by the following combination of characters: (1) the rostrum incised medially; (2) the anteromedial edges of lamellae separated almost as far posteriorly as insertion points of setae in; (3) the domed interlamellar region; (4) the anterior margin of notogaster transverse medially, then stepped posterior of bothridia; (5) epimera III and IV partly fused; (6) epimeral setation 3-1-2-2.

Remarks. Topalia caliginosa sp. nov. is morphologically most similar to T. royi sp. nov., with which it shares the semi-fused epimera III and IV, setae in on squat tubercles, the medially-separated lamellae and the pattern of angular foveolae of the notogastral cerotegument. Topalia caliginosa sp. nov. differs from T. royi sp. nov. in the transverse and stepped anterior margin of the notogaster, rather than wavy and indented medially; the smooth lamellae with a sparingly granular cerotegument, rather than with fine striae and with a divided rostrum rather than an entire one.

Figures

FIGURE 1. Topalia caliginosa sp. nov. (a) dorsal aspect; (b) ventral aspect; (c) lateral aspect. Scale bar = 100 µm.

FIGURE 2. Topalia caliginosa sp. nov. (a) prodorsum showing lamellae (LA) with part of right lamella removed, rostrum (RO) and tutorium (Tu); (b) subcapitulum and rutella (RU); (c) chelicera; (d) palp; (e) bothridum and bothridial seta. Scale bars = (a) & (b) = 50 µm; (c) & (e) = 25 µm; (d) = 15 µm.

FIGURE 3. Topalia caliginosa sp. nov. (a) Leg I; (b) Leg IV. Scale bar = 50 µm.

FIGURE 11. Prodorsal morphology of taxa included in the character analysis. Outgroups not illustrated. (a) Topalia caliginosa sp. nov.; (b) Nosybea genavensis Mahunka, 1993; (c) Lamellocepheus personatus (Berlese, 1910), based on Weigmann & Murvanidze (2003) and Mahunka & Mahunka-Papp (2009); (d) Microtegeus borhidii Balogh & Mahunka, 1974; (e) Charassobates cavernosus Grandjean, 1929; based on Grandjean (1958); (f) Neoeutegaeus sp. (Colloff, unpublished); (g) Licneremaeus braziliensis Bonfim, Silva & Oliveira, 2017; (h) Podopterotegaeus altimontanus Piffl, 1972.

FIGURE 12. Notogastral morphology of taxa included in the character analysis. Outgroups not illustrated. (a) Topalia caliginosa sp. nov.; (b) Nosybea genavensis Mahunka, 1993; (c) Lamellocepheus personatus (Berlese, 1910), based on Weigmann & Murvanidze (2003) and Mahunka & Mahunka-Papp (2009); (d) Microtegeus borhidii Balogh & Mahunka, 1974; (e) Charassobates cavernosus Grandjean, 1929; based on Grandjean (1958); (f) Neoeutegaeus sp. (Colloff, unpublished); (g) Licneremaeus licnophorus (Michael, 1882), based on Ito (1982); (h) Podopterotegaeus tectus Aoki, 1969.

FIGURE 14. Anogenital morphology of taxa included in the character analysis. Outgroups not illustrated. (a) Topalia caliginosa sp. nov.; (b) Nosybea genavensis Mahunka, 1993; (c) Lamellocepheus personatus (Berlese, 1910), based on Weigmann & Murvanidze (2003) and Mahunka & Mahunka-Papp (2009); (d) Microtegeus borhidii Balogh & Mahunka, 1974; (e) Charassobates cavernosus Grandjean, 1929; based on Grandjean (1958); (f) Neoeutegaeus sp. (Colloff, unpublished); (g) Licneremaeus licnophorus (Michael, 1882), based on Ito (1982); (h) Podopterotegaeus altimontanus Piffl, 1972.