Evolution of nuptial-gift-related male prosomal structures: taxonomic revision and cladistic analysis of the genus Oedothorax (Araneae: Linyphiidae: Erigoninae)
Author
Lin, Shou-Wang
Author
Lopardo, Lara
Author
Uhl, Gabriele
text
Zoological Journal of the Linnean Society
2022
2021-11-20
195
417
584
journal article
115951
10.1093/zoolinnean/zlab033
75b10efe-a17d-4d10-b46e-094c6a7ebf01
0024-4082
6967774
BE2B3859-8F6A-4543-8A69-91840F82377B
EMERTONGONE
GEN. NOV.
Type
species:
Lophocarenum montiferum
Emerton, 1882
.
Derivatio nominis:
The genus name is a combination of Emerton, in honor of the American arachnologist James Henry Emerton, the original describer of the
type
species, and the ending of the generic name ‘
Erigone
’. Genus gender feminine.
Diagnosis:
Males:
Small-sized, dark-brown-coloured erigonine. This genus is characterized by its male prosomal modification comprising a post-PME groove, post- PME lobe, the anteriorly protruded hirsute clypeus and the shorter distance from PLE to clypeal lower margin compared to PME. Despite its superficial partial similarity of prosomal modification with
Oe.
gibbosus
, this genus has no separate radix and embolus connected by a membranous region, and the embolic membrane is erected from distal part of distal suprategular apophysis. These characters distinguish it from all taxa in Clade 13.
Females:
Can be distinguished from all other examined taxa by the shorter distance from ALE to clypeus margin compared to distance from AME to clypeus margin, the hirsute clypeus, and the transverse slit on the epigyne between the two copulatory openings (
Fig. 65E, G
).
Species included:
Emertongone montifera
(
Emerton, 1882
)
comb. nov.
Phylogenetic justification:
Although the prosomal modification of
Em.
montifera
superficially resembles that of
Oe.
gibbosus
, the palpal configuration of this species is different from that of
Oedothorax
as delimited in the present study. In the phylogeny (
Fig. 2
), this species is sister to Clade 12; i.e. more closely related to the
Walkenaeria
and
Gonatium
representatives than to all
Oedothorax
,
Callitrichia
,
Mitrager
and other representatives in Clade 13. The similarity in prosomal morphology is, therefore, a result of homoplasy. After a comprehensive literature research of erigonine male palpal structures, no morphologically resembling species was found that can suggest at least a preliminary (i.e. phenetic) close relatedness. Base on these findings and its resulting phylogenetic placement, this species neither belongs to
Oedothorax
, nor can it be transferred to any other established taxon.We, therefore, propose the erection of
Emertongone
gen. nov.
for this unique species.