Plumachaetas yoshii, Zhang, Feng & Deharveng, Louis, 2015

Zhang, Feng & Deharveng, Louis, 2015, A revision of Pseudoparonella, Plumachaetas, Parachaetoceras and Lawrenceana (Collembola: Paronellidae), with description of three new species from New Caledonia, Zootaxa 4058 (4), pp. 561-577 : 570-572

Plumachaetas yoshii sp. nov.

Figs 23‒36

Types. Holotype: female on slide, New Caledonia: Riviere Bleue, alt. 170 m, Malaise trap, 26.iii‒9.iv.1987, L. Bonnet de Larbogne and J. Chazeau leg. (# ρ7(12)ε1). Paratypes: 3 female on slides and 9 in alcohol, same data as holotype. Two paratypes on slides in NJAU and others in MNHN.

Description. Length of body: up to 4.5 mm.

Ground colour pale yellow in alcohol. Antennae gradually dark from I to IV. Lateral stripes on Th. II‒Abd.I and Abd. IV. Th. III with a middle posterior narrow stripe. Abd. III with a transverse dark band. A pair of dorsal patches on middle and posterior Abd. IV ( Fig. 23). Ant. I‒II and legs with some long straight chaetae ( Fig. 23). Scales mostly pointed, coarsely striate, and present on Ant. I‒II, head, terga, legs, ventral tube, and ventral side of furcula ( Fig. 24 ).

Antenna 1.8 times as long as body length. Antennal segments ratios I: II: III: IV = 1: 1.3: 1.0: 3.0. Ant. III organ with 2 thin rod-like chaetae ( Fig. 25 ). Ant. IV apically with a thick spiny chaeta and without apical bulb ( Fig. 26 ).

Eyes 8+8; G and H much smaller than others. Prelabral and labral chaetae 4/5, 5, 4; prelabrals ciliate; chaetae of the p-row much longer than others and the median three thicker than lateral two ( Fig. 27 ). Lateral process of labial palp extremely short ( Fig. 28 ). Subapical chaeta of maxillary outer lobe thick and blunt ( Fig. 29 ); chaetae on sublobal plate not clear. Labial triangular chaetae as MREL1L2; all ciliate; R 0.8 times as long as chaeta M ( Fig. 30 ). Dorsal cephalic chaetotaxy as in Fig. 31 .

Th. II with 5 median and 12 posterior macrochaetae. Th. III with 15 central macrochaetae ( Fig. 32 ). Trochanteral organ with more than 50 smooth, spiny chaetae ( Fig. 33 ). A small ventrodistal swelling present on tibiotarsi. Unguis with 2 lateral and 3 minute inner teeth; lateral one at 0.40‒0.50 from base, inner pair with tip reaching 0.30‒0.45 from base of ventral edge, and distal one 0.72 from base. Unguiculus I‒III truncate with a corner tooth and an outer minute tooth. Tenent hairs clavate and shorter than unguis ( Figs 34, 35 ).

Abd. IV 7.0‒8.0 times as Abd. III in length along dorsal midline. Abd. I with 7 macrochaetae. Abd. II with 5 central and 3 lateral macrochaetae. Abd. III with 1 central and 4 lateral macrochaetae. Abd. IV centrally with 19‒22 anterior and 6‒7 posterior macrochaetae, and laterally with 12‒15 macrochaetae. Accessory microchaetae of bothriotrichal complexes on Abd. II–IV modified as scale-like chaetae. Tenaculum with 4 + 4 teeth and one large striate chaeta. Ventral tube anteriorly with 8 apically large chaetae and many ciliate small chaetae; posteriorly with more than 100 ciliate chaetae. Posterior face of manubrium without modified chaetae. Dens with many thick ciliate chaetae; a large distal socket present in all mounted-specimens with seta lost indicating distal one much larger than others. Mucro tridentate ( Fig. 36 ).

Etymology. Named after the collembologist R. Yoshii , who published major works on Paronellidae .

Remarks. This new species is similar to Pl. sunae sp. nov., Pl. halmaherae ( Yoshii & Suhardjono, 1992) and Pl. queenslandica ( Schött, 1917) in colour pattern, long antennae with long chaetae, thick subapical chaeta of outer maxillary lobe, scale morphology and mucro. Of the three species, Pl. yoshii sp. nov. has five elongate labral chaetae in the p-row (two in Pl. halmaherae , three in Pl. sunae sp. nov. and Pl. queenslandica ). Pl. queenslandica has the lanceolate unguiculus and the most abundant spiny chaetae on trochanteral organ, while other three have truncate unguiculus and fewer spiny chaetae. Of the tergal macrochaetotaxy, Pl. yoshii sp. nov. has 6, 5 central macrochaetae on Abd. I and II respectively, differing from 5, 5 in Pl. sunae sp. nov., 8, 4 in Pl. halmaherae and 4, 6 in Pl. queenslandica . Of the mucronal teeth, Pl. halmaherae has four, Pl. yoshii sp. nov. has three and Pl. sunae sp. nov. has two and as does Pl. queenslandica ( Table 2 ).

Figures

FIGURES 24 – 36. Plumachaetas yoshii sp. nov.: 24, body scales, tip rounded in the left and pointed in the right; 25, Ant. III organ; 26, Ant. IV apical chaetae; 27, labrum; 28, lateral process of labial palp; 29, maxillary outer lobe; 30, labial triangle chaetae, same as other two new species; 31, dorsal cephalic chaetotaxy; 32, dorsal body chaetotaxy from Th. II to Abd. IV (pseudopore not clearly seen on Abd. IV); 33, trochanteral organ; 34, mid claw; 35, hind claw; 36, mucro.