[Title Page] [List of Genera] Comparison of Drawings] [Regional Keys to Genera] [Descriptions of New Taxa] [Geographical Distribution] [Color Photographs] See also Catalogue of Salticidae [ Title page] List of Genera - names beginning with: A BC DEFG HIJKL MN OPQ RS TUVWXYZ References: Authors beginning with: A BC DEFG HIJKL MN OPQ RS TUVWXYZ See also Catalogue: Myrmarachne] List of species: Myrmarachne]
Remarks on relationship and definition
of genus Myrmarachne (Araneae: Salticidae)
from
Jerzy Proszynski 2001. Remarks on jumping spiders of the genus Damoetas related to Myrmarachne (Araneae: Salticidae) with description of two new species. Annales zoologici, Warszawa, 51 (4): 517-522, figs 1-10.
Traditional interpretation of relationship of
Myrmarachne and similar genera was based on ant like shape of the body
and possession of numerous teeth on retrolateral ventral margin of chelicerae.
Additional characters were eyes I arrangement (single line along upper rim,
with AME distinctly bigger than ALE), sternum elongate and thin, tibia I –
not expanded laterally. That was idea expressed in Simon’s group Myrmarchneae
(Simon 1901: 393, 496-503). Other interpretations concerned first of all on
ant like body and resulted in merging a number of Simon’s group of genera
into subfamily Myrmarachninae by Petrunkevitch 1928: 57, 182. Summing
up various traditional approaches Bonnet 1959: 5052 lists 22 genera classified
into Myrmarachninae, as opposed to other ant like subfamilies: Agorinae,
Peckhaminae and Synagelinae. Phyletic background inferred from
that approach was illustrated by Jackowska, Proszynski 1975: 40, fig 2.
Revisional study of type specimens and new material
carried out by Proszynski 1976, 1984,
1987, 1991, and in press, Berry, Beatty, Proszynski 1996, Edmunds, Proszynski 2003, also complementary
drawings to Philippine Myrmarachne species studied by Barrion and Litsinger
1995, available at this Internet site.
Davies, Zabka 1989 indicated, however, other kind
of similarities mutual to both Myrmarachne and other genera, not necessarily
ant like. Davies, Zabka 1989: 200, dealing with Australian fauna only, considered
Damoetas Peckham et Peckham, 1908, Ligonipes Karsch, 1878, Myrmarachne
MacLeay, 1839 and Rhombonotus L. Koch, 1879 a part of natural group Myrmarachninae;
they did not discussed non-Australian members of that group; the present paper confirm that view.
Variation in structure
in of a number of Myrmarachne species from Malaya peninsula are discussed
in Edmunds, Proszynski 2003, based also on analysis of over 170 species of
that genus, shown by Proszynski in the Internet monograph “Salticidae (Araneae)
of the World” .The common features of Myrmarachne and several presumably
related genera are palpal organ with round or oval bulbus, containing translucent
internal channel of sperm reservoir - which may make either broad loop along
the edges of bulbus, or, in many species, an additional small, narrow loop
in the middle of bulbus. Embolus is coiled around the bulbus – usually 2 or
3 times, and expanded by white membranous or fleshy expansion along majority
of its length. Tibial apophysis is surprisingly constant in many species,
short, either simple or bent, often with a flange, is ended hook like. Even
more striking is structure of epigynum with external membraneous "window"
bisected by translucent internal longitudinal dark channel like spermathecae,
which in front of the "window" form either sclerotised vesicles,
or a coil, single or numerous. The entrance copulatory channel is always membranous
and transparent, beginning medially and then making a complicated coil, folded
and with irregular outline, ultimately joining posterior end of sclerotised
vertical channels of spermathecae. It is usually overlooked, unless stained
with Chlorazol Black E (whose blue staining gradually disappear during preservation
in alcohol), and often damaged or removed during preparation, unless preparator
is aware of its existence and particularly careful. It was observed for the
first time by Proszynski 1992: 185-186, 187, figs 88, 92 and is found in every
species of that group since. The vertical sclerotised channels of spermathecae
have a small, porous structure just near junction with membraneous channels,
slightly expanded, being possibly an opening to scent gland, whose soft duct
is presumably always destroyed. The vertical sclerotised channels of spermathecae
run anteriorly and in front of white membraneous “windows” ends either as
slightly dilated part, or form single spherical bodies, or are bent into transversal
channel. Transversal channel makes a coil, single or multiple, and then return
to axial extension of original channels and ends with small swelling (always
with small porous structure, being presumably nutritional pores) and is joined
by soft, terminal fertilisation duct. The sclerotised terminal parts in front
of “windows” have usually internal walls covered with minute teeth.
There
emerges a problem: which of these various characters, body shape, cheliceral
features, or genital organs similarities are more relevant for determination of
relationship among ant like Salticidae. Examination of hundreds of species, and
diagnostic drawings of even more species, convinces me that above mentioned
kinds of characters do change independently, in a mosaic fashion. There seem to
be little correlation between cheliceral dentition, body shape, leg spination and
coloration. It cannot be proved yet that genital organs similarities has more
phyletic significance among species resembling Myrmarachne. But we can
accept that as a working hypothesis and see to which taxonomic conclusion it
can lead.
Copyright
© for the page by J. Proszynski, 2003.