Tectocepheus kumayaensis, Nakamura & Fukumori & Fujikawa, 2010

Nakamura, Y. - N., Fukumori, S. & Fujikawa, T., 2010, Oribatid Fauna (Acari, Oribatida) From The Kumaya Cave Of Iheya Village In Central Ryukyu Arc, South Japan, With A Description Of Several New Species, Acarologia 50 (4), pp. 439-477 : 447-450

Tectocepheus kumayaensis sp. nov.

[Japanese name: Kumaya-kuwagatadani] ( Figs. 6 and 7 )

Diagnosis — Body length 264 µm; width 178 µm. Rostral anterior margin without incision, broadly truncate with two concavities. Setae in trigonal pyramidal, roughened. Sensilli with globular head. Bothridia with deep incision, without swelling or projection. Depression and dorsosejugal scissure absent. Humeral region with small triangular projection. Ten pairs of notogastral setae. Genito-anal setal formula: 6-1-2-3. Lyrifissures iad located along, near anterior margin of anal aperture. Epimeral setal formula: 3-1-3-3. Trochantera III and IV bearing carina with sharply pointed apex. Monodactyl.

Material examined — Holotype (Female) (NSMT-Ac 13590) from point C.

Etymology — After the name of sampling point, Kumaya Cave.

PLATE 2: Oppiella (Oppiella) nova ( Oudemans, 1902) (photos by Nakamura Y.)

Measurements and body appearance — Body length 264 µm; width 178 µm. Body colour light brown. Whole body surface covered cerotegument; cerotegument irregularly granulate.

Prodorsum — Rostral anterior margin without incision, broadly truncate with two concavities ( Fig. 6A ). Setae ro (33 µm) and le (30 µm) spiniform, extending for a short distance anterior of rostral anterior margin; setae ro barbed unilaterally; setae le roughened throughout length; ro nearly as long as le. Lamellar cuspis without dent nor swelling, not extending to level of rostral anterior margin. Rostral and lamellar transverse ridges distinct. Setae in (5 µm) small trigonal pyramidal, roughened throughout length. Sensilli (45 µm) composed of thin, roughened stem and globular head which bears dark coloured spines. Setae ex (8 µm) smooth, short, longer than setae in. Bothridia opened anterolaterally, with deep incision, without swelling or projection.

Notogaster — Depression and dorsosejugal scissure absent. Humeral region with small triangular projection. Ten pairs of notogastral setae short setiform, roughened throughout length. Lyrifissures ia aligned perpendicular to notogastral outline, antero-laterally to setae c 2; im obliquely, laterally to lp; ip perpendicular to notogastral outline between p 1 and p 2. Setae h 3 inserted antero-lateral to gla.

Ventral region — Genital (36 µm) and anal (57 µm) apertures almost pentagonal in form; distance (22 µm) between them appreciably shorter than half length of anal aperture. Genito-anal setal formula: 6-1-2-3; all setae smooth setiform ( Fig. 6C ). Setae g 1 and g 2 inserted nearer anterior margine of plates. Setae ag inserted latero-posteriorly to genital aperture. Setae ad 1 and ad 2 aligned in postanal position, ad 3 in adanal. Lyrifissures iad located along, near anterior margin of anal aperture. Sternal ridge distinct at epimeres borders 2-4; bo. 1,2, sj distinct. Epimeral setal formula: 3-1-3-3; setae smooth, minute setiform. Diarthric subcapitulum bearing 3 pairs of setae: a (13 µm), m (2 µm) and h (11 µm); setae thin smooth setiform; relative lengths: a ≈ 6x h; m ≈ 4x h ( Fig. 6B ).

Legs — Monodactyl; claws with few dens. Legs not studied. Trochantera III and IV bearing carina with sharply pointed apex ( Fig. 7B ). On tarsus I, famulus ε trigonal pyramidal situated between solenidia bacilliform ω 1 and setiform ω 2 ( Fig. 7A ). Solenidion ’ 1 on tibia I originating from apophysis, about three times longer than the length of ω 1.

Remarks — Rostrum with two concavities of the new species is similar in appearance to those of Tectocepheus alatus Berlese, 1913 and T. shirakamiensis Fujikawa, 2001 . However, the new species differs from them in form of cuspis, dorsosejugal region, humeral region, and situation or direction of lyrifissures ia and iad. The new species has a small body size, verrucose globular sensilli and subpallel lyrifissures iad to anal aperture as is the case of T. minor Berlese, 1903 [1904] sensu Bernini (1973) and Japanese specimens collected by Fujikawa. At first she considered these Japanese specimens as T. cuspidentatus Knülle, 1954 ( Fujikawa, 1988) , because (1) she could not find out similar characters like rostrum with two deep incisions between Japanese specimens and Berlese Collection (204/6, 217/27- 30 and 82/36-40) in addition slides in the Berlese Collection were hardly examinable for her, and (2) she could find that Japanese specimens beared a stricking resemblance in the rostrum shape, sensilli and lamellar cusps, and situation of lyrifissures iad with a specimen of T. cuspidentatus in Zoological Museum Copenhagen. Latter the Japanese specimens were identified as T. minor ( Fujikawa, 2001) according to Nübel-Reidelbach (1994). After that, Mahunk and Mahunka-Papp (1995) and Laumann and al (2007) pointed out that T. minor has medially weakly protruding rostral anterial margin, cusps bearing inner and outer dens, globular sensilli, notogaster without depressions, bothridium ventrally expanded, trochanter IV bearing a dorsal spur and lyrifissures iad situated subparallel to anal aperture. Fujikawa (1995; 1999) could not observe individual variation in presence or absence of rostral incisions, form of rostral anterior margin, presence or absence of dens of cusps, and situation of iad subparallel to anal aperture. Now we consider that the abovementioned Japanese specimens should be reidentified as T. cuspidentatus . Tectocepheus minor by Fujita and Fujiyama (2001) should be also included in the species, T. cuspidentatus, Fujita and Fujiyama (2001) suggested that, unlike T. velatus , T. cuspidentatus could migrate in response to seasonal environmental changes. The new species differs from all the species of the genus in having rostral anterior margin with two concavities without incisions, cusps without dens and swelling, trigonal pyramidal interlamellar setae, and form of carina on trochanter III and IV.

Figures

FIGURE 6: Tectocepheus kumayaensis sp. nov. A, Dorsal view; B, Camerostome; C, Genito-anal region.

FIGURE 7: Tectocepheus kumayaensis sp. nov. A, Solenidial region on tarsus and tibia of leg I; B, Left epimeral region.