Akabosia matsudoensis Kinoshita, 1919

Figs 71-72, 73-78, 79-81, 82-87, 88-89

Akabosia matsudoensis Kinoshita, 1919: 16-20.

Examined specimens.

5♀♀ on slides, China, Jiangsu Province, Nantong City, Intersection of Tongning Highway and Pingning Road, 32°04'21″N, 120°50'19″E, sample number 1249, collected by Y-T Ma, 1-IX-2022, in the leaf litter of Salix babylonica .

Description of specimens from China.

Size. Body length up to 1.81 mm.

Coloration. Ground colour pale white to pale yellow. Eye patches dark blue. A little brown pigment present on antennae and Abd. V (Figs 71, 72).

Head. Antenna 0.70-1.03 times body length; antennal segment ratio I: II: III: IV = 1: 1.10-1.34: 1.10-1.40: 1.60-1.83. Apical bulb of Ant. IV simple (Fig. 73). Eyes 8 + 8, G and H smaller than others; interocular chaetae with p, r, and t mes. Dorsal cephalic chaetotaxy with five antennal (An1, An2a, An2, An3a1, An3), two median (M2, M4), and three sutural (S2, S3, S6) mac (Fig. 74). Labral chaetae as 2/5, 5, 4, prelabral chaetae ciliate, other smooth; labral margin with four papillae (Fig. 75). Basal chaeta of maxillary outer lobe thin, subequal to apical one; sublobal plate with three smooth chaeta-like processes (Fig. 76). Lateral process (l.p.) of labial papilla E differentiated, as thick as normal chaeta, with tip not reaching apex of papilla E (Fig. 77). Labium with ABCDF chaetae, all smooth, chaeta F apically blunt; chaetae of labial base as MRL1L2, all ciliate (Fig. 78).

Thorax. Th. II with one medio-medial (m2), three (p1-3, p4 rarely present) posterior mac, one ms and one sens (ms antero-enternal to sens). Th. III with five (p1-4, p4i) mac and one sens (Fig. 79). Trochanteral organ with 25-31 smooth spiny chaetae (Fig. 80). Tenent hair ciliate and longer than inner edge of unguis, with tip capitate. Unguis with three inner teeth, basal pair located at 0.41-0.50 distance from base of inner edge of unguis, distal one small and at 0.75-0.76 distance from base; inner lamellae of unguiculus truncate, external lamellae acuminate (Fig. 81).

Abdomen. Range of Abd. IV length as 9.21-10.45 times dorsal axial length of Abd. III. Chaetotaxy Abd. I-III as in Fig. 82. Abd. I with five (a1, a3, m2-4, a1 rarely absent, a3 sometimes absent), one ms. Abd. II with two (m3, m3e) central, one (m5) lateral mac. Abd. III with two (pm6, p6) lateral mac, one ms and one sens. Lateral part of Abd. IV with 10-12 mac. Middle part of Abd. IV with two (A1, Ae1) mac anteriorly; four (A3, B3, Be1, C1) mac centrally; four or five (B4, B5, A6, A4 and A5 sometimes absent) posteriorly (Fig. 83). Abd. V with three sens, middle one posterior to m3 (Fig. 84). Anterior face of ventral tube with 11-15 ciliate chaetae, 3+3 of them as mac, line connecting proximal (Pr) and external-distal (Ed) mac oblique to median furrow (Fig. 85); posterior face with many ciliate chaetae; lateral flap with five or eight smooth and seven or 24 ciliate chaetae (Fig. 86). Mucro rectangle and with two teeth apically and one small tooth medio-distally (Figs 87 - 89).

Remarks.

The genus Akabosia was established by Kinoshita in 1919 and it can be separated from its similar genus Salina by the crenulated dens (dens is not crenulated in Salina). Only one species, A. matsudoensis Kinoshita, 1919, has been reported in the genus and its localities include Japan (Kinoshita 1919; Yosii 1954, 1965), Korea (Mitra 1977) and China (Zhang et al. 2015). The characters of our specimens agree well with their description in colour pattern, chaetotaxy of dorsal body, labrum and mucro, and we describe some additional characters including maxillary outer lobe, labial papilla E, chaetotaxy of Abd. V for the first time. The medio-distal tooth on the mucro was overlooked previously as it is very small and located on the lateral side.