On the identity of the fossil aquatic beetles from the Tertiary localities in the southern part of the Upper Rhine Graben (Coleoptera, Hydrophilidae, Dytiscidae)
Author
Martin, Fikacek
Author
Hajek, Jiri
Author
Schmied, Heiko
text
ZooKeys
2011
78
15
25
http://dx.doi.org/10.3897/zookeys.78.800
journal article
http://dx.doi.org/10.3897/zookeys.78.800
1313-2970-78-15
Escheria punctulata
Foerster
, 1891
Fig. 9
Escheria punctulata
Foerster
1891
: 361; plate XI, Figs 8a,b (original description from Brunstatt);
Handlirsch 1908
: 767 (catalogue).
Hydrobius punctulatus
:
Theobald
1937
: 169 (transferred to
Hydrobius
);
Hansen 1999
: 319 (catalogue).
Taxonomic note.
Based on the drawing by
Foerster
(1891)
, the ventral morphology of this species agrees with that of
Hydrophilidae
:
Hydrophilinae
in many characters: (i) mesocoxae transverse and very narrowly separated, (ii) mesepimeron well separated, triangular, (iii) metanepisternum rather narrow; (iv) abdomen with five ventrites.
However
, none of these characters or their combination is unique for the
Hydrophiloidea
and may be found in other beetle families as well (see
Lawrence et al. 1999
). Moreover, two characters illustrated on the drawing and/or mentioned in the original description exclude the placement of
Escheria punctulata
in the
Hydrophiloidea
: (i) elytra bear only 6 deeply impressed striae [9-11 striae are present in all
Hydrophiloidea
with striate elytra, only rarely is the number of series higher but in such cases they are never impressed to striae]; (ii) mesoventrite fused with mesepisternal (i.e. not separated from them by sutures) [in
Hydrophiloidea
, the mesoventrite is fused to mesepisterna only in derived groups of the
Sphaeridiinae
which are characterized by a highly elevated median portion of the mesoventrite; the elevated median elevation is missing from the fossil]. For these reasons,
Escheria punctulata
is removed from the fossil record of
the
Hydrophiloidea
and is placed into
Polyphaga
incertae sedis; its family placement remains unclear.