segunda-feira, 12 de julho de 2010

Three new Mesozoic Staphylinids (Coleoptera) from Liaoning, China

Three new Mesozoic Staphylinids (Coleoptera) from Liaoning, China

Yanli Yue, Yunyun Zhao*, Dong Ren*

College of Life Sciences, Capital Normal University, 105 Xisanhuanbeilu, Haidian District, Beijing 100048, China a r t i c l e i n f o
Article history: Received 30 December 2008
Accepted 22 September 2009
Available online 26 September 2009
Keywords: Staphylinidae, Oxytelinae, New genus, Yixian Formation, China

a b s t r a c t

A new genus and three new species of well–preserved Oxytelinae are described and illustrated from the Yixian Formation of Beipiao City, Liaoning Province, in northeastern China. These three staphylinids are placed into a new extinct genus, Sinoxytelus gen. nov.: Sinoxytelus euglypheus sp. nov., Sinoxytelus breviventer sp. nov., and Sinoxytelus longisetosus sp. nov. This finding documents the first record of fossil Oxytelinae in China. Provisionally, we consider the age of the Yixian Formation as transitional between the Late Jurassic and the Early Cretaceous.
2009 Elsevier Ltd. All rights reserved.

1. Introduction

The subfamily Oxytelinae is one of the more ancient lineages in
Staphylinidae. The earliest known staphylinids are difficult to
assign to known subfamilies. The earliest named taxonwas actually
placed in the small subfamily Olisthaerinae, which is a close relative
of the subfamily Tachyporinae. Fossils with ages after the Late
Jurassic are usually reminiscent of extant species well enough to be
put into subfamilies, provided that they are well preserved and
multiple specimens can be examined.
Previously, three extinct genera have been described in Oxytelinae:
Mesoxytelus Tichomirova, 1968 with two species became
known from the Upper Jurassic Karatau Formation in Kazakhstan
(Tichomirova, 1968); Turgaphloeus Ryvkin 1990 and Morda Ryvkin
1990, both with a single species placed in the tribe Oxytelini,
described from the Lower Cretaceous Turga Formation in Russia
(Ryvkin, 1990).
Recently, we collected several well preserved Oxytelinae
impression fossils from the Yixian Formation in Huangbanjigou,
Chaomidian Village, Shangyuan Township, Beipiao City, Liaoning
Province, in northeastern China. Based on their unique characters,
we established one new genus with three new species.
The Yixian Formation consists of grey tuff, siltstone and
mudstone which have yielded insects, conchostracans, plants,
primitive birds and feathered theropods (Zhang, 2008). The age of
the biota is controversial with three different opinions.

Provisionally, we consider it as a transition from the Late Jurassic to
Early Cretaceous.

2. Material and methods

All type specimens of the new species are deposited at the Key
Laboratory of Insect Evolution & Environmental Changes, Capital
Normal University in Beijing, China. They were examined using
a Leica MZ12.5 dissecting microscope and illustrated with the aid of
a drawing tube attachment. Line drawings were made with Adobe
Photoshop CS graphic software. Photos were taken with a Nikon
DXM1200C digital camera. We follow the systematic arrangement
of Oxytelinae proposed by Makranczy (2006).
3. Descriptions of new taxa
Order: Coleoptera Linnaeus, 1758
Family: Staphylinidae Latreille, 1802
Subfamily: Oxytelinae Fleming, 1821
Tribe: Oxytelini Fleming, 1821
Genus: Sinoxytelus gen. nov.1
Type species: Sinoxytelus euglypheus gen. et sp. nov.
Etymology. From the combination of the Greek prefix Sino-
(China) and the genus name Oxytelus.
Diagnosis. apical maxillary palpi nearly as wide as, and longer
than penultimate one; longitudinal grooves along and behind
internal margin of eyes; gular suture completely separated;
mesocoxae moderately separated by internal process; trochantin
exposed; abdominal tergites 3–7 with curved basolateral ridge.
Comparison. The new genus described here can be referred to
Oxytelinae based on the following characters: (1) antennae of 11
antennomeres, not clubbed; (2) antennae inserted anterior to
a line drawn between anterior margins of eyes, distance between
antennae longer than that between mandibles; (3) every
abdominal segment with a pair of paratergites; (4) procoxae
prominent. The new genus can be assigned to the tribe Oxytelini
by abdominal segments with 7 visible and complete sternites, and
mesocoxae moderately separated by mesosternal process (Newton
et al., 2001) and mesocoxae moderately separated by mesosternal
process (Herman, 1970). At present, Oxytelini is composed of 23
extant and 3 extinct genera (Makranczy, 2006). Among the extinct
genera, the new genus described here is very distinct: it is
considerably larger than either of them; it has relatively large
head without distinct neck; and it has longitudinal grooves along
and behind internal margin of eyes. Contrary to Turgaphloeus and
Mesoxytelus, it has no indicated neck. Contrary to Morda, it has 5
(not 3) segments of tarsi. Additionally, unlike Mesoxytelus (with
longitudinal grooves on pronotum), Sinoxytelus has smooth pronotum.
Among recent genera, by the large size of the body,
Sinoxytelus resembles the genus Coprostygnus (tribe coprophilini);
but it differs from the latter in presence of basolateral ridge,
separated gular sutures and not very stout fourth segment of the
maxillary palpus.
The species within the genus Sinoxytelus can be distinguished by
the following key

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