Folsomia arunachalensis, Mandal, 2018

Mandal, G. P., 2018, Three new species of Collembola from India, Records of the Zoological Survey of India 118 (2), pp. 107-127 : 112-113

Folsomia arunachalensis sp. nov.

(Plate 2, Figures– 1–20, Table 3–4)

Type material: Holotype: Female on slide, INDIA, Arunachal Pradesh, Lower Dibang Valley District, 65 Mayudia , Altitude 2481 m., Latitude 28°14.103’N and 95°54.895’ E, date 03.xi.2015, coll. Dilip Mondal (Registration No. 1791/H14) deposited in the National Zoological Collection, Zoological Survey of India , (Kolkata) . Paratypes: 1 ex on slide, same data as Holotype

(Registration No. 1792/H14) and 50 exs in ethyl alcohol, same data as Holotype (Registration No. 1793/ H14) deposited in the National Zoological Collection, Zoological Survey of India, (Kolkata) .

Description: Body length up to 0.92 mm.

Colour: Ground colour creamy white, no pigmentation and ocelli ( Figure 1 ).

Head: Ommatidia absent. PAO broad, oval shape, without distinct constriction, with 3 guard setae ( Figure 2 ), PAO

1.3–1.4 times as long as width of Ant. I and 2.2 times more than inner edge of claw III. Maxillary palp bifurcated, maxillary outer lobe with 4 sublobal hairs ( Figure 3 ). Labral setal formula 4, 5, 4. Labium with 4+4 basomedian setae. Ventral side of head with 4+4 setae along linea ventralis (ventral grove). Ant. I, II, III respectively with 1, 1, 0 basal microsensilla (bm) and 2, 3, 3 sensilla (s). Ant. IV with weekly differentiated sensilla with apical lobe( Figures 4, 5, 6, 7 ).

Body chaetotaxy: Macroseta (Mac) obviously longer than ordinary seta. Sensillum (s) thinner-walled, shorter and more slender than common setae. Microsensillum (ms) thick–walled and shorter than common seta and sensillum ( Figures 8, 9, 10 ). Formula of body macrosetae Th– II, Th– III, Abd–I, II, III, V as 1, 1, 0, 1, 1, 5 per half tergum, longest on last 3 abdominal segment 2.77 times length of mucro. Sensillar and micro–sensillar formula respectively as 4, 3/2, 2, 2, 3, 5 (s) and 1, 1, 0 (ms) ( Figures 11, 12, 13 ). Medial sensilla on all tergites situated within P–row, on Abd. I– III between macrochaeta 1 and 2. Axial setae (common setae along median line on each side) of Th. II –Abd. III: 8–9, 9(10), 8(9), 8. Th. II with 20–22 setae in p–row.

Appendages: Unguis without lateral&inner teeth.Tibiotarsus with many additional setae. Ventral tube with 4+4 latero distal and 4–5 posterior setae ( Figure 14 ). Retinaculum 4+4 teeth and 1setae ( Figure 15 ). Tenent hairs absent. Anterior side of manubrium with 18 setae, posteriorly with 4 basal setae, of which 3 apical and 1 middle ( Figure 16 ); dens crenulated, anterior side with 22 setae, in two rows, posterior with 4 setae( Figures 17 and 18 ) and lateral side of dens with 11 setae ( Figure 19 ). Mucro with 2 teeth ( Figure 20 ), ratio of manubrium: dens:mucro as 5.1:8.5:1.

Etymology: The new species is named after the type locality.

Biology: In Arunachal Pradesh, found under the grasses, covered with dung of animals. The area is hilly and difficult terrain, covered with mixed vegetation of semi evergreen forests.

Discussion: Folsomia arunachalensis n. sp. belongs to the F. fimetaria group because of abdominal sensilla positioned in the p–row, ventral chaetae on Th. III usually missing and only one pair of macrochaetae present on thoracic segment (Potapov, 2001). The new species could be easily distinguished from all the known species of the genus by the body sensilla being 4, 3/2, 2, 2, 3, 5; setae on anterior side of manubrium being ‘18’ and anterior dental setae in two rows containing ‘20’ and other characters shown in Table 3.

Remarks: All species of the fimetaria group are blind, have no chaetae on ventral side of Abd. III and no or only 1+1 lateral sens thickened on Abd. V. The two main characters to discern the Folsomia species are ventral setae on the third thoracic segment and number of ventral setae on the distal region of the manubrium. The redescription of F. fimetaria by Lucianez and Simon, 2002 also clearly indicate that the absence of ventral setae on the third thoracic segment and manubrium with 4+4 ventral setae. The new species could be easily separated from other species in the fimetaria group by its particular body sensilla and chaetotaxy of manubrium and dens. Manubrium with 17 anterior setae arranged in 3+3, 3, 3–5 and posterior side of manubrium with 4 setae. Dens with 22 setae in anterior side arranged in two rows, posterior with 4 setae and laterally with 11 setae. Folsomia arunachalensis n. sp. is nearer to F. fimetaria ( Linnaeus, 1758) having without pigment and omma, maxillary pulp bifurcate, maxillary outer lobe with 4 sublobal hairs but strongly differs with other characters shown in Table 4.

Figures

Figures 1-22. Calx kailashi sp. nov. 1. Calx kailashi sp. nov. habitus (lateral view). 2. Calx kailashi sp. nov. habitus (lateral view). 3. Calx kailashi sp. nov. habitus (dorso- lateral view). 4. ventral view. 5. Antenna. 6. Apex of Ant. IV. 7. Apex of Ant.III. 8. Outer labral papillae. 9. differentiated external labial setae. 10. Eyes. 11. Dorsal cephalic chaetotaxy 12. Type of setae. 13. Cheatotaxy of Thorax..II– III. 14. Cheatotaxy of Abd.I–III. 15. Retinaculum. 16. Trochantral organ. 17. Tibiotarsal setae. 18. Hind foot complex. 19. Dorsal setae on Manubrium. 20. Mucro. 21. Male genital plate. 22. Type - locality of Calx kailashi sp.nov. at Panvasba Nallah, East side of Koderma Wild Life Sanctuary, district Koderma, Jharkhand, India.