Willowsia nigromaculata ( Lubbock, 1873 )

Katz, Aron D., 2017, A new endemic species of Willowsia from Florida (USA) and descriptive notes on all New World Willowsia (Collembola: Entomobryidae), Zootaxa 4350 (3), pp. 549-562 : 553-554

Willowsia nigromaculata ( Lubbock, 1873)

Figs 2 , 13 , 17

Material examined. USA: Illinois, Pope Co., Dixon Springs Ag . Center, 37.43435, -88.66718, elev. 524ft, hand collected on pavement on dying Arilus cristatus , 23Sep2011, A. Katz, adk11-159, 6 on slides ( INHS 810,157– 810,162 ), 30 in ethanol ( INHS 810,163 ) ; Illinois, Urbana, 19 Montclair Rd. , 40.094873, -88.206853, 6.vii.2008, by kitchen sink, F. Soto-Adames, 1 on slide ( INHS 810,164 ) ; Illinois, Urbana, 19 Montclair Rd. , 40.094873, - 88.206853, 2012, F. Soto-Adames, 1 on slide ( INHS 810,165 ).

Complement to description based on American specimens. Habitus as in Figure 2 . Scales long basal rib type ( Fig. 13 ) and absent on antennae, legs, and furcula. Dorsal chaetotaxy of the head as in Figure 17 : row An with 5 mac; anterior mac A0, A2, A3, A5 present; 3+3 median mac, M1, M2, M4 present, M3 always absent; sutural mac, S0, S2, S3, S 4i, S4, S 5i, S5 present, S6 as mic; posterior mac Ps5 absent. Outer maxillary lobe with 3 sublobal hairs. Prelabral setae ciliate. Labral papillae each with single seta-like projection. Labial triangle as MrEL1L2A1– 5, r always present. Lateral process of labial palp thin, curved, blunt, reaching tip of labial papilla E. Cephalic groove with 8+8 ciliate setae.

Ecology. This species occurs in leaf litter, and is also considered a nuisance species in North America as it is commonly found inside homes.

Distribution. Cosmopolitan, including North and Central America.

Remarks. Willowsia nigromaculata is the only member of the genus with the following combination of characters: color pattern as in Figure 2 ; long basal rib scale type ( Fig. 13 ); scales absent from antennae, legs, and furcula; labral papillae with a single seta-like projection; prelabral setae ciliate; labial triangle seta r present ; outer maxillary lobe with 3+3 sublobal hairs; dorsal head with 3+3 median mac, 6+6 sutural mac, mac S0 present, and mac Ps5 absent ( Fig. 17 ); Th. II with 1+1 median mac and 7+7 posterior mac; Abd. I with 3+3 mac; Abd. II with 3+3 inner mac; Abd. III with 3+3 inner and 3+3 lateral mac; and Abd. IV with 7+7 inner mac.

In the Americas, this species is most similar to W. buski : both have basal long rib scale type ( Zhang et al., 2011); scales absent on antennae, legs, and manubrium; labral papillae each with a single seta-like projection; ciliate prelabral setae, labial triangle r seta present, 3+3 sublobal hairs of outer maxilla; 3+3 median mac, 6+6 sutural mac, and mac S0 present dorsally on head; 3+3 inner mac on Abd. II; and 3+3 lateral mac on Abd. IV. They can be differentiated by color pattern and chaetotaxy: W. nigromaculata has a distinct dorsal pigment pattern, while W. buski is uniformly dark blue or purple without a clear pattern; dorsal head mac Ps5 is absent in W. nigromaculata (present in W. buski ); 1+1 median mac on Th. II ( W. buski has 2+2); 3+3 mac on Abd. I ( W. buski has 2+2); 3+3 inner mac on Abd. III ( W. buski has 2+2), and 7+7 inner mac on Abd. IV ( W. buski has 5+5). See Table 1 for additional diagnostic characters.

The specimens observed for this study matched morphological descriptions, including dorsal chaetotaxy, by Christiansen & Bellinger (1998) and Zhang et al. (2011).

Figures

FIGURES 1 – 4. Habitus: 1, Willowsia buski; 2, Willowsia nigromaculata; 3, Willowsia jacobsoni (male); 4, Willowsia jacobsoni (female). Scale bars = 200 µm.

FIGURES 5 – 14. Scales: 5 – 7, Willowsia pyrrhopygia sp. nov.; 8 – 10, Willowsia mexicana; 11, Willowsia jacobsoni; 12, Willowsia buski; 13, Willowsia nigromaculata; 14, Americabrya arida. Scale bars = 1 µm.

FIGURES 15 – 19. Head dorsal chaetotaxy: 15, Willowsia buski; 16, Willowsia jacobsoni; 17, Willowsia nigromaculata; 18, Willowsia mexicana; 19, Willowsia pyrrhopygia sp. nov. Scale bars = 100 µm.