On the species of the genus Desmidium from Hokkaido,Japan

Summary Six species and two varieties of the genus Desmidium from Hokkaido have been investigated. Among them one species (D. grevillii), one variety (D. aptogonum var. acutius) and three facies (D. pseudostreptonema, facies ovalis; D. aptogonum, facies quadrangularis; D. baileyi, facies ovalis) are new to Japan. Zygotes were observed in three species and one variety (D. swartzii, D. aptogonum, D. baileyi and D. coarctatum var. cambricum) and parthenospores in one species (D. aptogonum).

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Zusammenfassung 6 Arten und 2 Variet?ten von der Gattung Desmidium aus Hokkaido werden hier beschrieben und illustriert. Es wurden 1 Art (D. grevillii), 1 Variet?t (D. aptogonum var. acutius) und 3 Facies (D. pseudostreptonema, facies ovalis; D. aptogonum, facies quadrangularis; D. baileyi, facies ovalis) von diesen als neu für die Flora Japans angesehen. In den 3 Arten und 1 Variet?t (D. swartzii, D. aptogonum, D. baileyi und D. coarctatum var. cambricum) wurde Zygoten betrachtet und in 1 Art (D. aptogonum) Parthenosporen.

     

Oguraxylon,a new genus belonging to the family taxodiaceae,from the cretaceous of Hokkaido

Described is a new species belonging to a new genus of petrified wood,Oguraxylon yubariense sp. nov. It exhibits characteristics of the Taxodiaceae in general anatomy and closely resemblesTaxodioxylon sequoianum andT. albertense. It is, however, unique in having tertiary spiral thickenings on the walls of the tracheids, which have never yet been found in any extent or extinct species of the family.     

A new cottid species,Porocottus coronatus,from the Pacific coast of Hokkaido,Japan

A new cottid species,Porocottus coronatus, is described on the basis of nine specimens from the Pacific coast of eastern Hokkaido, Japan. It differs from other species of this genus by having a group of finger-like cirri on the dorsal midline of the head, long uppermost preopercular spine, 15–16 anal fin rays and well developed cephalic sensory system with many small pores.     

A new species of Haborophocoena, an Early Pliocene phocoenid cetacean from Hokkaido, Japan

A new species of phocoenid cetacean Haborophocoena , collected from the Early Pliocene Embetsu Formation, in the close vicinity to the site where the holotype of the type species of the genus Haborophocoena was retrieved, improves our knowledge of the anatomy of this cetacean. The new species, represented by a skull, lacking distal half of the rostrum, ear bones, and teeth, is significantly smaller than, but morphologically similar to, the type species Haborophocoena toyoshimai Ichishima and Kimura 2005 . This new record of Haborophocoena confirms the veracity of the genus Haborophocoena as a biological entity, contributes to understanding the interspecific variation, and suggests that the genus diversified in the northwestern Pacific of early Pliocene time. The adult-like degree of ossification in this small skull precludes it from being a juvenile of Haborophocoena toyoshimai . Autapomorphies of Haborophocoena minutus include narrow premaxilla on the dorsal surface of the rostrum, the anterior position of the premaxillary foramen, and a distinct ridge dividing a fossa on the lateral face of the base of the zygomatic process into the dorsal and the ventral halves, the zygomatic process rectangular in lateral profile, and its small size, which is the most compelling feature, making it a distinct species.     

New species of Microsporidia in the genus Amblyospora from blood-sucking mosquitoes in the family Culicidae

Two microsporidians of the genus Amblyospora from mosquito larvae of Aedes and Culex were studied in Tomsk region (Siberia). Peculiarities of the sporogony and the meiospore ultrastructure were studied by light and electron microscopy. The meiospores of A. caspius sp. n. from Aedes caspius and Ae. communis measured on smears, were c. 4.8 x 3.6 microns in size. A polar filament was anisofilar with 5 wide (290 nm) and 9 narrow (190 nm) coils arranged in a single layer. A polaroplast of both species was composed of two parts: anterior lamellae and posterior fibrillae. Meiospores of A. burlaki sp. n. from Culex pipiens measured c. 4.8 x 3.5 microns. A polar filament was anisofilar with 3 wide (260 nm) and 6 narrow (110 nm) coils. The meiospore of this species had a 260 nm thick multilayered exospore.     

Trigonognathus kabeyai,a new genus and species of the squalid sharks from Japan

Two specimens of the peculiar squalid shark,Trigonognathus kabeyai gen. et sp. nov., were collected from the coastal waters of Wakayama and Tokushima, Japan, by bottom trawl at depths of 330 and 360 meters. Shape of teeth similar in both jaws; slender, unicuspid, canine-like, without any cusplets or serrations, with weak thin fold on both lingual and labial sides in anterior teeth on both jaws; tooth at symphysis of each jaw longest. Interspace between teeth very wide. Both jaws triangular in shape. Most of dermal denticles on body and head roughly rhombic, swollen very much near central part, with about 10–40 facets on the dorsal surface of its crown. Preoral snout length very short. Many small organs considered to be photophores present mainly on ventral surfaces of head and body.     

Interspecific interactions among species of the coral genus Porites from Okinawa, Japan

Analysis of field established xenogeneic interactions among five Porites species from Sesoko Island, Okinawa, revealed a transitive type of hierarchy as: P. rus >P. cylindrica >P. lobata >P. australiensis>P. lutea. Out of the 111 interspecific encounters studied, in only 5.4% reciprocal interactions were recorded, and in a single case, the opposite directionality of hierarchy was documented. Allogeneic encounters were also observed. A single major effector mechanism, an overgrowth (together with secondary outcomes such as the formation of small points of rejection, bleaching and pink color formation along a narrow peripheral belt of contacting tissues), was the only response in all 10 xenogeneic and 5 allogeneic combinations. In some massive colonies, a long contacting line of up to 50 cm was established. No sign for allelopathy, stand-off or rejection from a distance (i.e., by sweeper tentacles, sweeper polyps) was observed. Results are discussed with the accumulated data on Porites species from different reefs, worldwide, confirming that this genus is commonly lower in the hierarchy of xenogeneic interactions.     

Neolumpenus unocellatus,a new genus and species of stichaeid fish from Japan

Neolumpenus unocellatus gen. et sp. nov., a stichaeid fish (subfamily Lumpeninae,sensu Makushok, 1958) is described on the basis of a single specimen found in the stomach of the Pacific cod,Gadus macrocephalus Tilesius, caught off Akkeshi, Hokkaido, Japan. The new genus and species is distinguished from all other lumpenines in having the following combination of characters: 1) 51 dorsal spines, 33 anal fin rays, 57 total vertebrae; 2) broad pelvic fin with deeply-branched soft rays; 3) lower rays of pectoral fin branched and not prolonged backward; 4) prevomerine and palatine teeth present; 5) pungent spines present in pelvic and anal fins; 6) upper lip fused to snout anteriorly; 7) gill openings not extending forward beyond a vertical through posterior margin of eye; 8) minimal (fifth) hypural present; 9) first interneural spine inserted between first and second neural spines; 10) extremely large cephalic sensory pores present; 11) high, steep snout; 12) ocellus on dorsal base of caudal fin.     

海南锥栗属新植物

1.五指山锥　别名 :山白锥 (五指山 )　新种　图版 - ACastanopsis wuzhishangensis　 G.A.Fu sp.nov.Species affinis Castanopsi carlesii( Hemsl.) Hayatavar.spinulosa,a qua folia crasoribus et duroribus dif-ferf.Etiam affinis C.Echinocarpae Miq.var.senin-udae,se     

Karyology of four land-planarian species of the genus Bipalium from Japan

We have employed a new scale for characterizing chromosomal forms in the karyotypes of four species of Bipalium from five localities in Japan. Specimens of Bipalium nobile Kawakatsu et Makino, 1982, from Yokohama had a diploid chromosome number of 2x = 10 (2m + 2sm + 2sm + st & sm + 2sm); specimens of the same species from Toyonaka had this number as well but with slightly different chromosomal form (2m + 2sm + sm & st + 2st + m & sm). An undescribed species from Sanjô, Bipalium sp. 2, with two dorsal stripes and a yellow head crescent, had 2x = 10 (2m + 2sm + 2sm + 2sm + 2m); and another undescribed species from Chichijima Island, Bipalium sp. 3, with five dorsal stripes, had 2x = 10 (2m + 2sm + 2sm + 2sm + 2m). A non-sexual bipaliid tentatively identified as Bipalium kewense Moseley, 1878, from Chichijima Island had 2x = 18 (2m + 2m + 2m + 2sm + 2st + 2sm + 2sm + 2sm + 2sm).     

A new cottid species, Icelus sekii (Perciformes: Cottoidei), from Hokkaido, Japan

A new cottid species, Icelus sekii, is described on the basis of six specimens collected from off Rausu and Urakawa, Hokkaido Island, Japan. This species is distinguished from its congeners by the following combination of characters: supraocular and parietal spines absent; nuchal spine obscure; uppermost preopercular spine unbranched; no scales between dorsal scale row and lateral line scale row, and no scales below lateral line scale row; supraocular, parietal, and nuchal cirri present; five dark brown saddles dorsolaterally; anal fin rays 13; pectoral fin rays 15; vertebrae 12 + 24–25 = 36–37. Icelus sekii can be mature at the smallest size among the species of Icelus. As a secondary sexual character, the male holotype has unique ensiform flaps on the distal tips of the first dorsal fin.     

Growth characteristics of six tree species on Hokkaido Island, northern Japan

Based on growth data obtained from 13 804 individual trees in 110 permanent plots, diameter at breast height (d.b.h.) growth was modeled for six major tree species growing in Hokkaido Island, northern Japan. For each species, d.b.h. growth was regressed on independent variables, indicating the effects of initial size, competition, climate and topography. In developing the d.b.h. growth models, independent variables were selected using the stepwise method. For all species analyzed, the final models accounted for significant amounts of the variation (r² = 5.65–20.99%; P < 5%) in d.b.h. growth. Significant (P < 5%) effects of competition, climate and topography on d.b.h. growth were detected. The model obtained can be used in simulations of forest dynamics. Some ecological questions were examined using the d.b.h. growth models obtained. For hardwoods, the d.b.h. growth rate did not correlate with the published grouping of species in terms of shade-tolerance; however, the plasticity in d.b.h. growth in the presence of competition seemed to be correlated with the shade-tolerance of species. The degree of asymmetry in competition evaluated for each species was not correlated with the availability of underground resources, which was expressed by surrogate variables (mean values of climatic and topographic variables for species). The degree of asymmetry in competition was not different between conifers and hardwoods.     

Tree mortality of five major species on Hokkaido Island, northern Japan

The mortality rates of five major tree species (Abies sachalinensis, Acer mono, Magnolia obovata, Quercus crispula, Tilia japonica) on Hokkaido Island, northern Japan were modeled using logistic regressions based on the long-term observation of 8929 individuals in 65 permanent plots. Individual size, recent growth, one-sided and two-sided interactions with neighbors, climatic and topographic factors were used as independent variables in the logistic regressions, and relevant variables were selected using the stepwise method. For all species analyzed, the final models significantly explained tree mortality rates. The regression analyses indicated that individual size and/or recent growth had effects on tree mortality. A significant effect of one-sided interaction on tree mortality was detected for three species, and a significant effect of two-sided interaction was detected for two species. The interactions with neighbors were not necessarily competitive. For all species analyzed, climatic and topographic factors affected tree mortality. The mortality models obtained can be used for forest dynamics simulations. One ecological question was examined using these models. Species that can grow fast in forest stands with smaller basal areas tended to have high mortality rates in forest stands with larger basal areas. Some ecological characteristics of the analyzed species are described based on the results of the regressions.     

Space partitioning among the wolf spiderPardosa amentata species group in Hokkaido,Japan

Population Ecology - There are 4 species belonging to the wolf spiderPardosa amentata species group in Hokkaido. The 4 species have separately occurred in Hokkaido in general, but a few species...     

Descriptions of two new species of the genus Lasioptera (Diptera: Cecidomyiidae) that infest tomato in the Mediterranean Region and Hokkaido,Japan

Applied Entomology and Zoology - Two new species, Lasioptera tomaticola Yukawa and Harris from the Mediterranean Region and Lasioptera yoichiensis Yukawa and Kim from Japan (Diptera: Cecidomyiidae)...     

Tsuga shimokawaensis,a new species of permineralized conifer leaves from the Middle Miocene Shimokawa Group,Hokkaido, Japan

Silicified pinaceous leaves from the late Middle Miocene bed of Shimokawa Town, central Hokkaido, Japan are described asTsuga shimokawaensis sp. nov. Comparisons with leaves of extant species ofTsuga show that the new species is assigned to sect.Tsuga, resembling the extant speciesT. heterophylla in having usually one-cell-layered hypodermis, andT. sieboldii in having mesophyll cells between the resin canal and the hypodermis. From cladistic analyses we infer thatTsuga shimokawaensis is positioned the basal in sect.Tsuga and that sect.Tsuga comprises four species groups.