The oldest records of Polyxenida (Myriapoda, Diplopoda): new discoveries from the Cretaceous ambers of Lebanon and France
Author
Duy-Jacquemin, Monique Nguyen
Histoire naturelle, Département Systématique et Évolution, Arthropodes, CP 53, 61 rue Buffon, F- 75231 Paris cedex 05 (France) monguyen @ mnhn. fr
monguyen@mnhn.fr
Author
Azar, Dany
Lebanese University, Faculty of Science II, Biology Department, BP 26110217 Fanar-Matn (Lebanon) and Department, Saint-Joseph University, Campus of Sciences and Technology, Mar Roukos (Mkalles), BP 11 - 1514 Beirut (Lebanon) azar @ mnhn. fr
azar@mnhn.fr
text
Geodiversitas
2004
26
4
631
641
journal article
10.5281/zenodo.4665318
1638-9395
4665318
Electroxenus jezzinensis
n. sp.
(
Figs 1
;
2
)
“Polyxenid millipede” –
Grimaldi 1996: 36
.
TYPE MATERIAL
. —
Holotype
: one adult specimen, number JS 231/1, Acra collection, provisionally deposited in the Muséum national d’Histoire naturelle, Paris (
MNHN
).
ETYMOLOGY. — After Jezzine, the
type
locality.
TYPE
LOCALITY AND
TYPE
HORIZON
. —
Jouar Es-Sous
locality,
Jezzine area
,
Caza of Jezzine
,
Mouhafazit Loubnan El-Janoubi
,
South
Lebanon
;
Lower Cretaceous
, Valanginian-Hauterivian (135-125 million years). The amber piece is mounted on a microscope slide in
Canada
balsam medium
.
FIG. 2. —
Electroxenus jezzinensis
n. gen., n. sp.
, holotype adult (JS 231/1), Acra collection;
A
, right latero-dorsal part of head with ocelli group and five basal antennal articles;
B
, distal articles of left antenna;
C
, right antenna;
D
, three distal articles of right antenna;
E
, trichomes on tergite II;
F
, right palpus of gnathochilarium;
G
, right leg III from femur to telotarsus;
H
, right telotarsus leg IV;
I
, distal right leg I;
J
,
K
, hooked caudal trichomes. Abbreviation:
t
, trichobothria. Scale bars: A, E, G, I-K, 20 µm; B-D, 40 µm; F, 50 µm; H, 25 µm.
DIAGNOSIS. — As for genus.
DESCRIPTION
Adult (
Figs 1
;
2
)
Grimaldi (1996: 36)
figured the habitus of the same specimen without giving a description. The sexual organs, penis or vulvae, normally located at the base of the second pairs of legs are not preserved; in addition the state of preservation of the coxae does not allow observation of the absence or the presence of coxal glands, hence the sex cannot be determined.
Measurements.
Body length =
2.25 mm
; penicil length =
0.70 mm
; head trichomes length =
0.18 mm
; total length =
3.10 mm
.
Head.
Six visible ocelli (
Fig. 2A
), but more might be present. The longer anterior trichomes of vertex are
200 µm
long. Eight antennal articles. Length of right sixth article 2.5 times the diameter. Three or four sensilla basiconica observed on the seventh article, more visible on the right antenna. Three (perhaps four) thin sensilla basiconica visible on right article VI: two or three long and a third that seems shorter than the two others (
Fig. 2
B-D). Elongated lateral expansion of palp with at least 17 sensilla, but perhaps more (
Fig. 2F
). Labrum not visible.
Trunk.
The long, thin trichomes of the tergites are grouped into two, separate, oval clusters with an additional posterior row, subdivided in its middle (
Fig. 2E
). The longer lateral trichomes of tergites reach
150 to 160 µm
; the trichomes of posterior row are only
70 to 95 µm
long. Only 12 pairs of legs are visible. Some pubescent cylindrical setae visible on coxae. Spine of tarsus II longer than the claw (
Fig. 2G, I
). Telotarsus with well visible posterior lamellate process longer than claw (
Fig. 2
G-I) and one anterior spinous denticle seen on several telotarsi. Telson with caudal penicil not of same
type
as
Polyxenus
Latreille, 1803
and
Propolyxenus
Silvestri, 1948
(
Condé 1969
)
; trichomes of caudal penicil with five, six (
Fig. 2K
) or seven (
Fig. 2J
) aligned hooks).