Willowsia jacobsoni (Börner, 1913)

Mandal, Pritha, Mandal, Guru Pada, Suman, Kusumendra Kumar, Bhattacharya, Kaushik Kumar & Kumari, Simran, 2024, Taxonomic insight on some newly recorded species of the springtails (Hexapoda: Collembola) from North Eastern and Eastern states of India, Journal of Insect Biodiversity and Systematics 10 (2), pp. 215-229 : 221

Willowsia jacobsoni (Börner, 1913) ( Fig. 5).

Material examined. 5 specimens, India, West Bengal, Alipurduar district , Dhowla Jhora Tea Garden, N 26°34'12'', E89°41'24'', 64.9 m a.s.l., 06-II-2023, leg. P. Mandal., reg. no- 3395/H14 .

Diagnosis. Average adult body length 1.7 mm (two specimens). General body colour dull white to pale yellow with dark blue bands on Th. II, Abd. III and posterior 1/4 of Abd. II & Abd. IV. Antennae become gradually darker from apex of Ant. II. Blue-brown pigment patch present on all tita. No other pigment patches observed in our specimens ( Fig. 5A). Body scales are with long basal rib type, manubrial scales elongated. Ant. IV with a unilobed apical bulb. Antennal segment ratio I: II: III: IV- 1: 2.4: 1.3: 2.6. Ant. III sensorial organ with two rods. Antennae: head diagonal- 1: 2. Labral chaetae formula as 4/5, 5, 4, pre-labral chaetae ciliated. Labral intrusion with more than one denticles. Tip of lateral process of the labial palp reaching the apex. Head chaetotaxy same as per Katz (2017) ( Fig. 5B). Unguis with internal basal paired, two unpaired teeth, tenet hair clavate, larger than the unguis ( Fig. 5C). Trochanteral organ with 18–20 spines. Retinaculum quadridented ( Fig. 5D). Dens crenulated and without spines, smooth part 2 times as mucro in length. Mucro bidentate with a basal spine, reaching sub-apical tooth ( Fig. 5E) .

Distribution in India. West Bengal (Darjeeling).

General distribution. West Africa, Madagascar, Continental South East Asia, Malaysia, Hawaii, Melanesia & Micronesia, Antillean & South Florida, Caribbean Mainland, Australia ( Bellinger et al., 1996 –2024).

Remarks. The previous distribution of Willowsia in India from Himachal Pradesh and Jammu & Kashmir ( Mandal, 2018) was wrongly interpreted. After rechecking the slides, it becomes obvious that they were another species of Willowsia which were misidentified. Here we are providing an updated distribution of Willowsia jacobsoni from West Bengal, India. The specimens were collected from the ant nest of Caesalpinia pulcherrima plant.