The epigean Australasian species of Neobidessodes gen. n. diving beetles- a revision integrating morphology, cybertaxonomy, DNA taxonomy and phylogeny (Coleoptera: Dytiscidae, Bidessini)
Author
HENDRICH, LARS
Author
HAWLITSCHEK, OLIVER
Author
BALKE, MICHAEL
text
Zootaxa
2009
2009-11-12
2288
1
1
41
http://dx.doi.org/10.11646/zootaxa.2288.1.1
journal article
10.11646/zootaxa.2288.1.1
1175-5326
10093582
Neobidessodes
Hendrich & Balke
gen.n.
(
Figs 1–21
)
Type
species
.
Bidessus denticulatus
Sharp, 1882
by present designation.
Diagnosis.
Neobidessodes
Hendrich & Balke
gen.n.
is assigned to the Bidessini based on the bisegmented parameres of the aedeagus (
Figs 17
,
18
) (
Biström 1988
). It is a genus of small to medium sized Bidessini (
2.3–4.2 mm
), in
Australia
now represented by eight species and by one species in southern New
Guinea
.
Etymology.
The name
Neobidessodes
is derived from the Greek word
Neo
[new] and
Bidessodes
, a valid genus name for a group of Neotropical predaceous water beetles. Its gender is masculine.
The new genus is well separated from all other Bidessini by the combination of the following combination of characters: 1) body elongate oval; 2) basal pronotal striae in some species absent or fine, in others sharply incised, oblique, not connected by a transverse groove; 3) elytra lacking basal striae and sutural striae; 4) epipleura lacking transverse carina; 5) head lacking cervical line and its foremargin not bordered; 6) prosternal process broad, distinctly excavated and marginated; 7) inner margin of both metacoxal wings strongly ridged; 8) hind margin of abdominal ventrites 3–5 without row of minor irregular dentate processes; 9) well-developed finger-like apical lobe on distal segment of paramere. All but two (
N. limestonensis
and
N. gutteridgei
) of the species studied have a more or less contrasting black/yellow surface. The ground pattern of these species includes various yellow or reddish spots (
Figs 1–12
). The median lobes are simple and very elongate, in ventral view strongly tapered or rounded at tip.
The Neotropical genus
Bidessodes
can be separated from Australian
Neobidessodes
gen.n.
by having 1) a non excavated and marginated prosternal process, and 2) a visible distinct row of minor irregular dentate processes on the hind margin of the abdominal ventrites 3–5.
Molecular systematics.
Our phylogenetic analyses show (
Fig. 27
) that
Neobidessodes
gen.n.
is not part of the
Allodessus
/
Limbodessus
, the
Uvarus
/
Gibbidessus
/
Kakadudessus
or the
Leiodytes
/
Clypeodytes
clades. It is rather part of a separate lineage sister to the first two clades. The DNA sequence data from the mitochondrial cytochrome
c
oxidase 1 and 16S rRNA genes also show that
Neobidessodes
gen.n.
does not belong to any of the known Oriental and Australasian Bidessini genera (the morphologically strongly deviating
Borneodessus
Balke, Hendrich, Mazzoldi & Biström, 2002
was not available for sequencing). Our data show that Australian
Neobidessodes
gen.n.
are not closely related to South American
Bidessodes
and recognition of
Neobidessodes
gen.n.
does not create paraphyly among other Australasian genera. This result is well supported in all analyses (
Fig. 27
). Essentially the same tree topology was recovered with different analytical approaches (maximum likelihood, parsimony and Bayesian probabilities as implemented in MrBayes,
Fig. 27
, node support values).
Remarks.
The placement of the two stygobitic species in this genus was primarily based on evidence from
cox1
and 16S sequence data (
Watts & Humphreys 2003
) which suggested a relationship of the two species with
N. bilita
(
Watts, 1978
)
,
N. mjobergi
(
Zimmermann, 1922
)
and/or
N. flavosignatus
(
Zimmermann, 1922
)
. A subsequent, comprehensive analysis of Australian stygobitic Bidessini and their epigean relatives (
Leys
et al
. 2003
) suggests a sister-group relation of the stygobitic and the epigean
Neobidessodes
(under the name
Bidessodes
at the time). There are no morphological characters that would negate their placement in
Neobidessodes
as currently defined. Our species level
cox1
data analysis (
Fig. 28
) confirms the sister-group relationship between stygobitic and epigean
Neobidessodes
.