20th International Congress of Arachnology

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Poster presentation
Extant primitively segmented spiders have
recently diversified from an ancient lineage
Xin Xu1,2, Fengxiang Liu2, Ren-Chung Cheng4 , Jian Chen2 ,
Xiang Xu1, Zhisheng Zhang6, Hirotsugu Ono7, Dinh Sac
Pham8, Y. Norma-Rashid9, Miquel A. Arnedo10, Matjaž
Kuntner2,4,5, Daiqin Li3
1College of Life Sciences, Hunan Normal University,
Changsha, China; 2 Centre for Behavioural Ecology
and Evolution (CBEE), College of Life Sciences, Hubei
University, Wuhan, China; 3Department of Biological
Sciences, National University of Singapore, Singapore,
Singapore; 4Evolutionary Zoology Laboratory, Biological
Institute ZRC SAZU, Ljubljana, Slovenia 5 Department
of Entomology, National Museum of Natural History,
Smithsonian Institution, Washington, DC, USA; 6 Key Lab-
oratory of Eco-environments in Three Gorges Reservoir
Region (Ministry of Education), School of Life Science,
Southwest University, Chongqing, China; 7Department of
Zoology, National Museum of Nature and Science, 4-1-1
Amakubo, Tsukuba-shi, Ibaraki-ken 305-0005, Japan;
8Institute of Ecology and Biological Resources (IEBR),
Vietnamese Academy of Science and Technology (VAST),
8 Hoang Quoc Viet, Cau Giay, Hanoi, Vietnam; 9 Institute
of Biological Sciences, Faculty of Science, University of
Malaya, Kuala Lumpur 50603, Malaysia; 10Institut de
Recerca de la Biodiversitat, Departament de Biologia
Animal, Universitat de Barcelona, Avinguda Diagonal
643, Barcelona 08028, Spain
Living fossils are lineages that have retained plesio-
morphic traits through long time periods. It is expected
that such lineages have both originated and diversified
long ago. Such expectations have recently been chal-
lenged in some textbook examples of living fossils,
notably in extant cycads and coelacanths. Using a
phylogenetic approach, we tested the patterns of the
origin and diversification of liphistiid spiders, a clade
of spiders considered to be living fossils due to their
retention of arachnid plesiomorphies and their exclu-
sive grouping in Mesothelae, an ancient clade sister to
all modern spiders. Facilitated by original sampling
throughout their Asian range, here we provide the
phylogenetic framework necessary for reconstructing
liphistiid biogeographic history. All phylogenetic analy-
ses support the monophyly of Liphistiidae and of eight
genera. As the fossil evidence supports a Carboniferous
Euramerican origin of Mesothelae, our dating analyses
postulate a long eastward over-land dispersal towards
the Asian origin of Liphistiidae during the Palaeogene
(39–58 Ma). Contrary to expectations, diversification
within extant liphistiid genera is relatively recent, in
the Neogene and Late Palaeogene (4–24 Ma). While no
over-water dispersal events are needed to explain their
evolutionary history, the history of liphistiid spiders has
the potential to play prominently in vicariant biogeo-
graphic studies.
Keywords: biogeography, systematics, vicariance, disper-
sal, ancestral areas
Oral presentation
Evolutional pattern of the mimic-model
relationship in the genus Myrmarachne
(Araneae: Salticidae)
Takeshi Yamasaki1, Yoshiaki Hashimoto2, Tomoji Endo3,
Fujio Hyodo4, Takao Itioka5
1Makino Herbarium, Tokyo Metropolitan University,
1-1 Minami-osawa, Hachioji-shi, Tokyo 192-0397,
Japan; 2Institute of Natural and Environmental
Sciences, University of Hyogo/Museum of Nature and
Human Activities, Hyogo, Japan; 3School of Human
Science, Kobe Collegae, Hyogo, Japan; 4Research Core
for Interdisciplinary Sciences, Okayama University,
Okayama, Japan; 5Graduate School of Human and
Environmental Sciences, Kyoto University, Kyoto,
Japan
The genus Myrmarachne MacLeay, 1839 comprises the
species that show ant-like appearance and behavior,
and they are considered to be Batesian mimics. In
fact, the ant-like appearance works effectively to get a
protection against predators that dislike ants (Huang
et al 2011; Nelson & Jackson 2006). However, the
model ant of each Myrmarachne species has not been
204 DENVER MUSEUM OF NATURE & SCIENCE REPORTS | No. 3, July 2, 2016
Cushing