Sinella cavernarum ( Packard, 1888 )

Wu, Jun, Yan, Qibao & Zhang, Feng, 2016, Supplementary descriptive notes of the Sinella and Coecobrya (Collembola: Entomobryidae) species from North America, Hawaii and Japan, Zootaxa 4085 (4) : -

Sinella cavernarum ( Packard, 1888)

Figs 17–32

Degeeria cavernarum Packard, 1888

Entomobrya lucifuga Folsom, 1902

Entomobrya (Parasinella) cavernarum Bonet, 1931 Parasinella cavernarum Bonet, 1942

Sinella (Parasinella) cavernarum Gisin, 1944

Type locality. Wyandotte Cave , Harrison, Indiana, USA.

Material examined. Two topotypes, female and male on slides, USA: Indiana: Wyandotte Cave , 27.viii.1928, leg. C. Bolivar and R. Jeannel, slide labeled as “ Bonet det. 1931”, deposited in MNHN. One slide per locality , USA: Ohio: Adams: Morrison's Cave , 2.vii.1980 (# 4618) ; USA: Ohio: Ottawa: Kindt's Cave , 14.vii.1980 (# 4619) ; USA: Ohio: Wyandot: Mine , 10.vii.1980 (# 4620) ; USA: Ohio: Highland: Kessler's Cave , 1.vii.1980 (# 4623) ; USA: Ohio: Ottawa: Duff's Cave , 15.vii.1980 (# 4627) ; USA: Maryland: Garrett: John Friend's Cave , 6.vii.1988 (#7063); deposited in CARC.

Redescription. Body length up to 2.6 mm. Body whitish.

Antenna 2.1 times as long as cephalic diagonal. Antennal segments ratio as I: II: III: IV = 1: 1.8: 1.7: 2.6. Ant.III organ not clearly seen. No apical bulb.

Eyes absent. Labral papillae absent. Prelabral and labral chaetae 4/ 5, 5, 4, all smooth ( Fig. 17 ). Dorsal cephalic chaetotaxy with 5 sutural (S) and 5 mac in Gr. II ( Fig. 18 ). Lateral process of labial palp straight, as thick as normal chaetae, with tip slightly beyond apex of labial papilla ( Fig. 19 ). Subapical chaeta of maxillary outer lobe slightly larger than apical one; 3 smooth sublobal hairs on maxillary outer lobe. Labial chaetae as m 1m 2rel1l2, all smooth; chaeta r 0.8 length of chaeta m; chaetae X, X2–4 smooth ( Fig. 20 ).

Trochanteral organ with 16 smooth spiny chaetae; 12 in arms and 4 between them ( Fig. 21 ). Inner differentiated tibiotarsal chaetae ciliate with ciliations moderately appressed to axis; inner outstanding macrochaetae 2, located at about 0.33 distance from base, ciliate and tapered at tip. Unguis with 3 inner teeth; paired ones unequal. Unguiculus lanceolate and outer edge weakly serrate. Tenent hair I–III pointed in one MNHN specimen, and II–III clavate in another MNHN specimen, subequal to unguiculus in length ( Figs 22–24 ). Abd.IV 2.9 times as long as Abd.III along dorsal midline. Tenaculum with 4 + 4 teeth and one large striate chaeta. Ventral tube anteriorly not clearly seen; posteriorly with 10 smooth chaetae ( Fig. 25 ); each lateral flap with 9 smooth chaetae ( Fig. 26 ). Manubrium without smooth chaetae. Manubrial plaque not clearly seen. Distal smooth part of dens 1.8 times as long as mucro. Mucro bidentate with basal spine short, its tip just reaching apex of subapical tooth; apical tooth much longer than subapical one ( Fig. 27 ).

Th.II with 4 (m1, m2, m 2i, m 2i 2) medio-medial, 6 medio-lateral, about 30 posterior mac, 1 ms, and 2 sens; m5, p4, p 4i, p 4i 2, p5, p5pi as mac; ms external to sens ( Fig. 28 ). Th.III with about 42 mac and 2 lateral sens ( Fig. 29 ). Abd.I with 7 (m2–4, m 2i, a2, a3, m4p) mac, 1 ms, and 1 sens. Abd.II with 6 (a2, a3, m3, m3e, m3ea, m3ep) central, 1 (m5) lateral mac and 2 sens. Abd.III with 3 (a2, a3, m3) central, 3 lateral (am6, pm6, p6) mac, 1 ms, and 2 sens ( Fig. 30 ). Abd.IV with 7 (I, M, A5, A6, B4–6) central and about 14 lateral mac ( Fig. 31 ). Abd.V with 3 sens ( Fig. 32 ).

Ecology. Most from caves.

Distribution. Illinois, Indiana, Pennsylvania, Columbia, Kentucky, Tennessee, Missouri, Maryland, Ohio.

Remarks. This species has long apical tooth on mucro, labial chaetae m 1m 2rel1l2 and abundant tergal mac. The chaetotaxy represents the typical Nearctic fauna of Sinella . Christiansen & Bellinger (1980, 1998) doubted that it could be separated into several taxa because of wide records in North America and variation in ungual structure and chaetotaxy. Because many details of specimens from non-type localities were not available, we didn’t resolve their doubt in this study.

Figures

FIGURES 17 – 27. S. cavernarum: 17, labrum; 18, dorsal cephalic chaetotaxy; 19, lateral process of labial palp; 20, ventral chaetae of head; 21, trochanteral organ; 22, for claw; 23, mid claw; 24, hind claw; 25, posterior face of ventral tube; 26, lateral flap of ventral tube; 27, mucro.

FIGURES 28 – 32. Dorsal chaetotaxy in S. cavernarum: 28, Th. II; 29, Th. III; 30, Abd. I – III; 31, Abd. IV; 32, Abd. V.