On the genus Hermippus Simon, 1893 (Araneae: Zodariidae, Zodariinae) in India with the description of three new species from the Western Ghats and proposing a new biogeographical hypothesis for the distribution of the genus
Author
Sankaran, Pradeep M.
Author
Jobi, Malamel J.
Author
Joseph, Mathew M.
Author
Sebastian, Pothalil A.
text
Zootaxa
2014
3893
1
114
126
journal article
10.11646/zootaxa.3893.1.5
88264cca-af41-4906-ade0-1e7cae1447c5
1175-5326
230449
BA1E5A6D-FB15-47BD-BDFA-F661689CAC2C
Hermippus gavi
sp. nov.
Type
material.
Holotype
: Female (
ADSH
10901303):
India
, Kerala, Pathanamthitta,
Gavi
(
9o26'09.07''N
and
77o09'56.78''E
),
3942 ft
. alt., Pradeep M. S. leg.
21 December 2013
, by hand.
Diagnosis.
Females of
H. gavi
sp. nov.
can be recognized by the presence of highly sclerotized epigyne with ‘W’ shaped median septum (Figs 15a & 17a), the oval, obliquely placed spermathecae (
Fig 17
b) and the characteristic dorsal opisthosomal pattern (
Figs 14a
& 20).
Description.
FEMALE (
Figs 14a–14
d, 16 & 20): Carapace uniform coquelicot, shiny, finely granulated, almost glabrous. Fovea longitudinal, reddish. Eyefield black. Clypeus black, finely granulated. Chilum triangular, wider than long, dark brown. Chelicerae black, promargin with two teeth, while retromargin without teeth or denticles. Labium and maxillae light brown; maxillae scopulated. Sternum yellowish-orange, posterior tip short, sharp, with poorly defined inter-coxal extensions. Opisthosoma oval, hairy, dorso-laterally black; dorsum provided with a characteristic pattern of chalk-white patches (
Figs 14a
& 20); lateral opisthosoma with a narrow, longitudinal, roughly zig-zag chalk-white stripe; venter grayish with a few chalk-white stripes. Spinnerets yellowish; spigots big and conspicuous (Fig 20). Posterior ventral spines present, arranged in two rows (Fig 16). Legs yellowish-orange; tarsi rebordered, with 4–7 short spines. Palpal segments yellowish-orange with dark brown tarsus. Body length 7.21. Prosoma length 3.48, prosoma width (at the middle) 2.73, prosoma thickness (at the middle) 2.04. Opisthosoma length 3.73, opisthosoma width (at the middle) 2.82, opisthosoma thickness (at the middle) 2.62. Eyes diameter: AME 0.16. ALE 0.22. PME 0.15. PLE 0.22. Eye interdistance: AME–AME 0.10.
PME–PME 0.25. AME–ALE 0.37. PME–PLE 0.50. AME–PME 0.16. ALE–PLE 0.08. Clypeus height at AMEs 0.76, at ALEs 0.56. Chilum length 0.17, width 0.42. Chelicera length 1.11. Measurements of palp and legs. Palp 2.54 [0.78, 0.51, 0.46, 0.79], I 8.72 [2.36, 1.01, 1.91, 2.02, 1.42], II 8.79 [2.43, 1.04, 1.85, 2.12, 1.35], III 8.47 [2.34, 1.02, 1.71, 2.24, 1.16], IV 10.04 [2.49, 1.05, 2.01, 2.96, 1.53]. Leg formula: 4213. Spination. Palp. femur 0 200, patella 1010, tibia 3213, tarsus 4054; legs: femora
I–II 1300
, III–IV 0500; patella I 0 0 0 0,
II–IV 1000
; Tibia
I 1006
,
II 2016
,
III–IV 2136
; metatarsus
I 1016
,
II 1017
, III 4044, IV 4048; Tarsi I–II 0 0 0 4, III 0 0 0 7, IV 0 0 0 6. Copulatory organ (Figs 15a, 15b, 17a & 17b): Epigyne simple and nearly rectangular (Figs 15a & 17a). Posterior border line of the epigyne thick with a median concavity (Figs 15a & 17a). Median septum W–shaped, highly sclerotized (Figs 15a & 17a). Spermathecae oval, obliquely placed, without definite copulatory duct or head (Figs 15b & 17b). Fertilization duct with a sharp proximal bent, lies in close contact with the proximo-lateral part of spermathecae (
Fig 17
b).
Male.
Unknown
Etymology.
The specific epithet is a noun in apposition and is referring to the
type
locality of the species. Gender masculine.
FIGURES 14a–14d, 15a–15b & 16.
Hermippus gavi
sp. nov.
14a Female (holotype) habitus, dorsal view; 14b Female habitus, ventral view; 14c Female habitus, retrolateral view; 14d Female, frontal view. 15a Epigyne; 15b Internal duct system. 16 Posterior ventral spines.
FIGURES 17a–17b.
Hermippus gavi
sp. nov.
Female copulatory organ. 17a Epigyne; 17b Internal duct system. CO = Copulatory opening; FD = Fertilization duct; MS = Median septum; PB = Posterior border line of the epigyne; SH = Spermathecal head. Scale bars: 17a, 0.16 mm; 17b, 0.15 mm.
FIGURES 18, 19 & 20.
Hermippus
spp., Female opisthosoma showing the characteristic dorsal pattern. 18
H. globosus
sp. nov.
19
H. inflexus
sp. nov.
20
H. gavi
sp. nov.
Scale bars: 18, 0.47 mm; 19, 0.48 mm; 20, 0.53 mm.
Natural history.
H. gavi
sp. nov.
inhabits semi-deciduous forest.
Distribution.
At present known only from the
type
locality in Kerala, Southern
India
.
Note.
All the described Oriental
Hermippus
species (
Fig 21
) can be separated from those of the Afrotropical species by four homoplasious characters: presence of posterior ventral spines (PVS) in front of the spinnerets, absence of external tooth on the cheliceral fang, absence of dorsal abdominal scutum and rebordered tarsi of legs. By considering these, all the described species of
Hermippus
can be categorized into two species groups:
The
cruciatus
–group:
Represented by all the five described Oriental species including
H. cruciatus
Simon, 1905
,
H. arjuna
Gravely, 1921
,
H. globosus
sp. nov.
,
H. inflexus
sp. nov.
,
H. gavi
sp. nov.
The
loricatus
–group:
Represented by all the seven described Afrotropical species including
H. loricatus
Simon, 1893
,
H. affinis
Strand, 1906
,
H. schoutedeni
Lessert, 1938
,
H. septemguttatus
Lawrence, 1942
,
H. minutus
Jocqué, 1986
,
H. tenebrosus
Jocqué, 1986
and
H. arcus
Jocqué, 1989
.
Two hypotheses can be suggested to explain the migration of the genus
Hermippus
from Africa to
India
: one through
Madagascar
before its separation from
India
or through ‘Oman-Kohistan-Dras
Island
Arc’. If the first hypothesis is true, then
Madagascar
should have representatives of an African genus like
Hermippus
. But
Hermippus
species are not recorded so far from
Madagascar
. It is already hypothesized that migration of zodariid genera like
Cydrela
Thorell, 1873
and
Hermippus
from Africa to the Oriental Region might have occurred after the separation of Indian plate from
Madagascar
(
Dankittipakul
et al.
2012
). It is therefore plausible that the migration of
Hermippus
spp. from Africa to Indian subcontinent occurred after its separation from
Madagascar
through the ‘Oman-Kohistan-Dras
Island
Arc’.
After its African origin, probably during the Early Cretaceous around 105 MYA after the separation of South
America
from Africa,
Hermippus
species might have started their migration to Indian subcontinent around 65–60 MYA by the end of the Cretaceous during the Cretaceous–Tertiary (K/T) period. During this time, the Indian subcontinent, during its northward drift to Asia, reattached to northeast Africa through the land bridge formed of a volcanic island arc named Oman-Kohistan-Dras Island Arc, which may have provided the crucial biotic link between Africa and
India
during the Late Cretaceous (
Chatterjee & Scotese 2010, fig 7.3
). The ‘Oman-Kohistan- Dras Island Arc’ hypothesis was proposed as an alternative for the ‘Greater Somalia’ hypothesis proposed by
Briggs (2003)
,
Chatterjee & Scotese (1999)
and
Chatterjee & Rudra (1996)
. The ‘Greater Somalia’ hypothesis was proposed to explain the existence of a continental corridor promoting faunal migration between
India
and Africa during the Late Cretaceous time. However, this hypothesis was rejected (
Chatterjee & Scotese 2010
) as the ‘Greater Somalia’ broke up from Africa during the Late Triassic-Early Jurassic time due to the spreading of the Neotethys. Before the reattachment with Africa, Indian subcontinent had separated from
Madagascar
also. The
cruciatus
—group of
Hermippus
might have migrated from Africa to Indian subcontinent after its separation from
Madagascar
through the land bridge of Oman-Kohistan-Dras Island Arc. After reaching the Indian subcontinent, the
cruciatus
—group of
Hermippus
might have faced and survived the second and third phases of the fatal Deccan volcanic eruptions happened in the Indian subcontinent around 65 MYA, one of the major causative factors resulted in the Cretaceous–Paleogene (K/Pg) mass extinction (
Keller
et al.
2009
) and one of the species of the
cruciatus
—group (
H. cruciatus
Simon, 1905
) extended its habitat into
Sri Lanka
also (
Fig 21
).