Revision of the genus Cephalobyrrhus of Japan and Taiwan (Coleoptera, Limnichidae)

Abstract Japanese and Taiwanese species of the genus Cephalobyrrhus are revised. A new species, C.amamisp. n., is described from Amami-Ôshima, the Ryukyus, Japan. This species is clearly distinguished from the other known species by the short and pointed median lobe and long phallobase. Two previously known species from Japan and Taiwan, C.latus and C.japonicus, are redescribed.

In this paper, the Japanese and Taiwanese species of the genus are reviewed, and the description of a new species is provided.

Materials and methods
The materials examined in this paper are deposited in the following institutions: EUMJ Ehime University Museum, Matsuyama, Japan TARI Taiwan Agricultural Research Institute, Taichung, Taiwan SEHU Systematic Entomology, Hokkaido University, Sapporo, Japan NMW Naturhistorisches Museum, Vienna General observations and dissections were made under a Leica MZ95 stereomicroscope. Microstructures of the dissected parts in pure glycerin were studied under an Olympus BH-2 compound microscope. After observation, the dissected parts were mounted on the same card with the specimen. Photographs were taken under the Leica MZ95 and combined in Helicon Focus ver. 4.70.5 Pro (Helicon Soft Limited).
Morphological terminology follows Hernando and Ribera (2005). Morphological abbreviations used in the measurements are as follows: EL length of elytra in suture; EW maximum width of elytra; PL length of pronotum in median line; PW maximum width of pronotum; TL total length (PL+EL).
The average is given in parentheses after the range.
Remarks. This genus is similar to Erichia Reitter, 1895 (= Jaechobyrrhinus Pütz, 1991), in general appearance, but differs from the latter in the following characteristics (Pütz 1991): body oblong, gently tapering posteriorly (elongate and subparallel-sided in Erichia); pronotum rounded in anterior and posterior corners (pointed in Erichia), posterior margin bisinuate (with two rounded extensions in Erichia). Most species of this genus have similar external features and intraspecific variation, and cannot be reliably identified without examination of the male genitalia (Pütz 1998).    Description. For full description see Pütz (1998). Antennae (Fig. 2E) 3E) with long and slender lateral struts. Aedeagus 0.6 mm; phallobase slightly tapering basally, with straight basal projection; parameres relatively wide, obtuse at apices, slightly arcuate in lateral sides, 0.42 times as long as phallobase; median lobe widened in basal 1/3, obtuse at apex, 0.88 times as long as parameres.

Key to males of the species of the genus Cephalobyrrhus of Japan and Taiwan
Female. Spiculum ventral (Fig. 3F) long, as long as ovipositor. Ovipositor (Fig. 3G) well sclerotized, long; coxite gently pointed at apices; approximate ratio of coxite and baculus (n = 1) as 1.0 : 5.0.
Biological notes. This species is common in Taiwan, and lives in a natural forest of a mountainous area. Immature stages are unknown.
Measurements of adults (unsexed; n = 20 Remarks. This record is the first of this species from Tsushima. Biological notes. This species lives in natural forests (particularly in the Japanese beech tree zone, above ca. 1,000 m elevation) near a small stream (Fig. 5A, B). The adults were observed on the surface of rocks and fallen rotten wood during the daytime, and were sometimes attracted to light. Overwintering probably occurs in the larval stage. Immature stages are unknown.  Diagnosis. The new species C. amami sp. n. has a short and pointed median lobe and a long phallobase.
Description. Adults. Body oblong, convex dorsally, shiny, densely covered with short golden setae. Coloration of body black; antennomeres I-II, maxillae, labial palpi and legs pale brown, but infuscate in apical part of tarsomeres V.
Remarks. This species is clearly distinguished from the other two known species in the region by the short and pointed median lobe and long phallobase.
Etymology. The species is named after the type locality. Biological notes. This species lives in a natural forest near a small stream (Fig. 5C, D). The type series was collected from the surface of fallen rotten wood during the daytime. Immature stages are unknown.