The crab spider genus Tarrocanus Simon, 1895 with notes on the genera Alcimochthes Simon, 1895 and Domatha Simon, 1895 (Araneae: Thomisidae)
Author
Ileperuma Arachchi, Ilesha S.
Author
Benjamin, Suresh P.
text
Zootaxa
2019
2019-06-06
4613
3
587
593
journal article
26577
10.11646/zootaxa.4613.3.10
1a9205b6-b1c8-4f35-814f-15df27982b4c
1175-5326
3239825
B193E70D-FC46-44A5-97AA-14DB0AF30AA1
Genus
Tarrocanus
Simon, 1895
Type
species
:
Tarrocanus capra
Simon, 1895
: 979
: fig. 1047.
Diagnosis.
Species of
Tarrocanus
can be readily distinguished from other thomisid genera by the following characteristics: vertical and broad clypeus, elevated ocular area with slightly curved anterior row, enlarged prominent lateral eye tubercles (arrows in
Figs 1, 2, 4, 5
), tubercles of PLE larger than that of the other eyes and are either modified with prominent triangular shaped tooth-like projections (in
T. capra
) or without such modifications (
T. jaffnaensis
sp. nov
) and horseshoe shaped marking on the centre of prosoma starting from the base of PLE tubercles.
Tarrocanus
can be separated from
Alcimochthes
and
Domatha
by the strongly recurved anterior margin and posteriorly broader opisthosoma.
Description.
Small spiders, body size 2.5-3.0. Prosoma brown, laterals dark brown, clypeus, ocular area, middle of prosoma light brown with whitish hue, widest at the centre, horseshoe-shaped markings on the centre, outlined by whitish yellow lines (
Figs 1, 2
), covered with sparsely distributed long setae and sub-erect weak setae. Opisthosoma lighter than prosoma, covered with numerous spots and patches of reddish brown, dark brown and greyish white, anterior half strongly recurved, bell-shaped, covered with sparsely distributed short setae. Eyes with enlarged, yellowish brown, partly jointed tubercles, both eye rows recurved. Eye formula: ALE>PLE>PME>AME, triangular shaped tooth-like projection on PLE (prominent only in
T. capra
). Clypeus vertical and broad, chelicerae yellowish brown, legs pale with parsley distributed spines and setae. Palp: tegulum simple and round with no apophyses, VTA with long stem and hook-shaped, embolus either moderately long and slender or short, curved and stout. RTA rudimentary, ITA may or may not be present. Females are unknown.
Composition.
Two species:
T. capra
and
T. jaffnaensis
sp. nov
.
Distribution.
Currently known only from
Sri Lanka
.
Remarks.
Close relationship of
Tarrocanus
and
Alcimochthes
is confirmed by molecular data (Ileperuma Arachchi & Benjamin, in press). The extent of the relatedness of
Domatha
to
Tarrocanus
and
Alcimochthes
is yet unknown due to unavailability of molecular data for
Domatha
. A well represented sample, including species of the three genera (both sexes) is essential to evaluate their relationships and to corroborate their generic boundaries in morphological terms.