Cryophilic Isotomidae (Collembola) of the Northwestern Rocky Mountains, U. S. A.
Author
Fjellberg, Arne
text
Zootaxa
2010
2513
27
49
journal article
10.5281/zenodo.196078
3afa748f-2467-40ae-83ec-00984bfe7362
1175-5326
196078
Desoria garibaldii
sp. n.
(
Figs. 44–49
,
115F
)
Type
material
(all in alcohol, sex not checked).
Holotype
and 60
paratypes
from "
Canada
, B.C., Garibaldi Park, Helm Glacier,
49o57'N
,
123o0'W
,
02.IX.1983
. Muddy blue ice at terminal lobe,
1,770 m
alt. A. Fjellberg 398/83" (
INHS
). Other material:
USA
, Alaska, Ptarmigan Glacier, summer 2003, P. Hartzell leg; Washington, Snohomish Co., Honeycomb Suiattle Glacier,
12.VIII.2002
, snow pack on glacier ice, P. Hartzell leg.; same county,
Columbia
Glacier,
04.VIII.2002
, snow pack on glacier ice, P. Hartzell leg; same state, Whatcom Co., Easton Glacier,
48o44''N
,
121o50'W
,
04.VIII.2002
, on snow, P. Hartzell leg.
Description
. Body size up to
1.6 mm
. Body shape slender, typical
Desoria
(
Fig. 115F
). Head shape normal. Abd. 5–6 almost completely fused, with a weak incision between the tergites and a distinct break in setal cover. Colour completely black, including extremities. Head without white spots between eye-fields. Freshly collected specimens with a greenish lustre. Unlike most species even small juveniles as dark as the adults. Ocelli 8+8, rather small. PAO oval, about 1.5 as long as diameter of nearest ocellus. Three setae associated with PAO (
Fig. 48
). Ant. 1 with 5–8 short curved ventroapical sensilla and a few curved setaceous sensilla (
Fig. 45
). Ant. 2 with a single ventrolateral curved sensillum in apical position. Ant. 3 organ, with a few additional sensilla (
Fig. 46
). Ant. 4 with bifurcate pin seta and a small apically expanded peg in the subapical organ. Labrum with 4/554 normal setae, apical edge with 4 sharp ridges and a composite ventral ciliation. Frontoclypeal field with 10–15 setae, two setae between antennal base and upper corner of labrum. Maxillary palp bifurcate, 4 sublobal setae. Labial palp complete, guard e
7
present; terminal seta on the papillae as long as guards. Hypostomal papilla with subequal H and h1/h2. Labial base with 5(4) median and 5 lateral setae. Head with 4+4(3) postlabial setae. Mandibles normal, strong. Maxillae unmodified, with 3-toothed capitulum and short lamellae densely covered with fine denticles. Integument smooth. Ground cover of setae uniform and dense, not markedly "double" (cf.
Fig. 30
) except on dorsal side of head and thorax. Macrochaetae smooth, short, poorly differentiated from ordinary setae. Median macrochaeta on abd. 5 only 1.0–1.2 as long as inner length of last claw. Sensillary formula in a juvenile specimen as 55/44456, spine-like microsensilla 10/001 (
Fig. 44
). On abd. 1–4 sensilla set slightly anterior to p-row; anterior sensilla present on abd. 4–5. Ventral tube on each side with 1+1 frontal and 5–6 lateral setae, posterior side with 4–6 setae. Retinaculum with 4+4 teeth and 9–15 setae. No ventral setae on thorax. Manubrium with blunt apical teeth and 2–3 short ventroapical setae on each side, ventromedial field with many (>40) setae. Dens dorsally crenulated, with 20–30 dorsal setae extending beyond mid point; ventroapical seta not prolonged. Mucro short and compact, with 4 sharp primary teeth. Inner lateral lamella not reaching tip of subapical tooth and so forming a small secondary tooth; lateral seta absent (
Fig. 49
). Tibiotarsi with 11 apical setae, all acuminate. Inner side of tib.1–2 with 3–4 setae along each side of median line. Claws with small lateral teeth, a weak inner tooth may be present on anterior two pairs of claws; unguiculus with a high dorsal lamella (
Fig. 47
). Males present, reproductive individuals not seen.
Etymology
. The new species is named after the
type
locality, Garibaldi Provincial Park in British
Columbia
. The park itself was named in honour of Guiseppe Garibaldi (
1807–1882
), the Italian revolutionary who paved the way for a unified
Italy
.
Discussion.
The species is recognised by the dark colour, short body setae, compact mucro and many dorsal setae on dens. It is close to
D. cancellarei
Christiansen et Bellinger, 1980
, described from snow in Iowa, but this latter species is pale blue and has only 6+6 ocelli and longer abdominal setae (longest abdominal macrochaetae at least twice as long as inner edge of last claw). Also
garibaldii
has a 4-toothed mucro, while the mucro has 5 teeth in
cancellarei
.
Distribution and ecology
. Common and abundant on and near snow and glacier ice in the northwestern Rocky Mountains in Alaska, British
Columbia
and Washington (details see above).