First fossil Molinaranea Mello-Leitão, 1940 (Araneae: Araneidae), from middle Miocene Dominican amber, with a phylogenetic and palaeobiogeographical analysis of the genus
Author
Saupe, Erin E.
Author
Selden, Paul A.
Author
Penney, David
text
Zoological Journal of the Linnean Society
2010
2010-04-30
158
4
711
725
http://dx.doi.org/10.1111/j.1096-3642.2009.00581.x
journal article
10.1111/j.1096-3642.2009.00581.x
0024-4082
4890027
MOLINARANEA
MELLO- LEITÃO, 1940
Type
species:
Molinaranea molinai
Mello-Leitão, 1940
Diagnosis:
See
Levi (2001)
.
Distribution:
Recent species are found in
Chile
,
Argentina
, the
Falkland Islands
, and Juan Fernandez Island. The fossil species is found in
Dominican Republic
amber (this paper).
Remarks:
Molinaranea
was created as a monotypic genus by Mello-Leitão in 1940; the gender is feminine.
Levi (2001)
used the paramedian apophysis to help distinguish amongst genera of
Araneidae
, a structure that is unfortunately not discernable in our specimen. A filiform (thread-like) embolus is visible adjacent to the conductor, however, and distinguishes our specimen from members of
Parawixia
Pickard- Cambridge 1904 and
Ocrepeira
Marx 1883
, which have robust emboli. Furthermore, our specimen can be placed with confidence within
Molinaranea
for the following reasons: the median apophysis is prominent, forked, and projects away from the palpal bulb. Although this morphology occurs in other genera, such as
Parawixia
,
Spilasma
Simon, 1897
, and
Ocrepeira
(
Levi, 1992
,
1993
,
1995
), the details differ from those in our specimen. For example, our specimen and members of
Molinaranea
have prongs that do not re-curve as prominently as those in members of
Ocrepeira
.
In those members of
Ocrepeira
that do have median apophysis prongs, the prongs are usually of unequal thickness, differing from the quasi-equal prong widths in
Molinaranea
and our specimen (
Levi, 1993
). Members of both
Ocrepeira
and
Parawixia
have median apophyses that typically thicken distally, whereas members of
Molinaranea
and our specimen thin distally (
Levi, 1992
,
1993
). Members of these same genera also possess many processes, bumps and/or indentations on the median apophysis, unlike the smoother median apophyses present in
Molinaranea
and our specimen. Additionally, many
Parawixia
species
with forked prongs on the median apophysis possess numerous (more than three) tubercles on the opisthosoma (more than the two present in our specimen). In
Spilasma
, the median apophysis is commonly trifid distally, with relatively short prong lengths, unlike the bi-forked prongs in
Molinaranea
.
Male members of
Spilasma
also possess a ventral, sclerotized area extending from the sides of the pedicel to the genital groove (
Levi, 1995
), a feature lacking in our specimen.