山﨑 健史

Abstract Salticidae (jumping spiders) usually exhibit pronounced sexual dimorphism in adult morphology, particularly body coloration and size and shape of the first legs. Consequently, the male and female from the same species might be erroneously assigned to different species or even different genera, which could generate synonymies in classification if only morphological data were used. Phintella is a species‐rich genus of Salticidae, which currently exhibits 76 named species. However, the male–female counterpart is unknown for nearly half of the species. In this study, we used a molecular approach to delineate the species boundaries for Phintella and Phintella‐like specimens collected in Vietnam, using morphological information as supporting data. We used three gene fragments (mitochondrial COI, 16S‐ND1, and nuclear 28S) and biogeographical considerations for species delimitation. A total of 22 putative species were recognized: 18 species of the genus Phintella, one species of the genus Lechia (L. squamata), and three species of the genus Phinteloides. Eleven undescribed species were discovered, of which seven have a male–female combination, two species have only males, and two species have only females. The crown age of Phintella was estimated at the Serravallian stage of the Miocene after the increase of species number around 16 MYA. The crown ages of most putative species recognized in this study were estimated in the Pleistocene, and the divergence among sister species likely occurred from the mid‐Miocene to the Pliocene. Our ancestral range reconstruction results showed that the diversification of our ingroup was governed by progressive dispersal events, i.e., Phintella and their related species in Vietnam diversified while expanding their range on the continent. Our results provide fundamental biodiversity data for a high‐diversity genus in Vietnamese Phintella spiders.

The genus Utivarachna Kishida, 1940 currently comprises 23 species, with eight described from Borneo. We examined the type materials of the Bornean species, except for U. fukasawana Kishida, 1940, as well as newly collected specimens. As a result, we describe a new species, Utivarachna itiokai sp. nov., which belongs to the dusun-group. We also provide the first description of the female of Utivarachna ichneumon and redescribe the known Utivarachna species of Borneo.

The female of Idastrandia orientalis (Szombathy 1915) is described for the first time, with redescription of the holotype male. Female specimens collected from the type locality share the somatic morphology of the holotype male, especially in the presence of a serrated retrolateral tooth on the chelicerae. On the basis of coloration and external morphological similarities, we conclude that our female specimens are conspecific with Idastrandia orientalis.

Phintella aequipeiformis Zabka, 1985 was described from a male and P. lucai Zabka, 1985 from a female, but the opposite sex of each nominal species remained unknown. Both were collected from the same habitats of the same localities in our field work, and they share some similarities in the body color pattern. Moreover, our results from DNA barcoding show that both are one and the same species. We therefore place P. lucai in the synonymy of P. aequipeiformis, and provide a redescription of the species on the basis of both sexes.

A new species of the genus Castoponera Deeleman-Reinhold, 2001, Castoponera christae sp. n., is described here. The species is closely related to C. lecythus Deeleman-Reinhold, 2001, but can be distinguished by the structures of the male palp and the female genitalia.

To evaluate the pattern of co-occurrence between ant-mimicking jumping spiders and sympatric ants in a tropical rainforest, we sampled these arthropods and also non-mimicking jumping spiders by net-sweeping from the understory vegetation in Sabah, Malaysian Borneo. We collected the spiders and ants from a total of 594 sample points, with ants occurring in 445 points (79.4%), non-mimicking jumping spiders in 308 (51.9%), Agorius ant-mimicking spiders in 40 (6.7%), and Myrmarachne ant-mimicking spiders in 59 (9.9%). Frequencies of occurrence of non-mimicking jumping spiders showed no significant difference in relation to ant-occurrence, whereas both of the ant-mimicking spider genera occurred significantly more frequently with ants. Agorius spiders co-occurred with a wider variety of different ant genera, compared to Myrmarachne, but logistic regression analyses and a null model test showed no specific associations between Agorius spiders and the sympatric ant genera. The mimetic resemblances of Agorius spiders are considered to be much less ant-like than those of Myrmarachne spiders, because their constriction of the cephalothorax is not as obvious as in Myrmarachne. These data provide support for the multi-model hypothesis (Edmunds 2000), which predicted that a poor ant-mimic should occur in ranges of many different ants, compared to good ant-mimic.

A new species of ant-mimicking jumping spiders, Myrmarachne tamsuiensis, is described using specimens from Tamsui, Taiwan. The female of the species is in external appearance similar to that of M. vulgarisa, whose female is known. However, they are distinguishable from each other mainly by the structure of the epigyne. © Arachnological Society of Japan.

Twenty-two species of the genus Myrmarachne are reported from Borneo in the present study. Among those, eight are new to science, M. acromegalis sp. nov., M. alticephalon sp. nov., M. brevichelicera sp. nov., M. crassembolus sp. nov., M. cyrtodens sp. nov., M. endoi sp. nov., M. lambirensis sp. nov. and M. sabahna sp. nov. The following synonymies are proposed: Myrmarachne topali Żabka, 1985 syn. nov. as a junior synonym of M. hanoii Żabka, 1985, M. gigantea Żabka, 1985 syn. nov. as a junior synonym of M. maxillosa (C. L. Koch, 1846). The females of M. assimilis Banks, 1930, M. biseratensis Badcock, 1918, M. gedongensis Badcock, 1918, M. markaha Barrion &amp Litsinger, 1995 and M. shelfordii Peckham &amp Peckham, 1907 are described for the first time. Copyright © 2013 Magnolia Press.

Two new species of the genus Myrmarachne are described (M. acutidens sp. n., M. epigealis sp. n.), and M. macrognatha and M. melanocephala are redescribed from Flores specimens. The females of M. macrognatha are recorded for the first time.

A new ant-like spider species, Myrmarachne latithoracica, is described using the specimens from the Central Ryukyus and Taiwan.

Myrmarachne borneensis G. Peckham &amp E. Peckham, 1907 and M. shelfordii G. Peckham &amp E. Peckham, 1907 are redescribed here based on type specimens. The lectotype of M shelfordii is designated. © Arachnological Society of Japan.