201,526 research outputs found
Letter to Grace H. Shimada
No full textCondolence letter to Mrs. Grace H. Shimada regarding the death of her husband George M. Shimada
Meristogenys dyscritus Shimada, Matsui, Yambun & Sudin, 2011, sp. nov.
No full textMeristogenys dyscritus sp. nov. Amolops sp. A: Matsui, 1979, p. 340, figs. 26, 28A; Amolops amoropalamus: Matsui, 1986, p. 628–629 (part); Meristogenys amoropalamus (lineage 3, lineage 4): Shimada et al., 2007 a, p. 173–189; Shimada et al., 2008, p. 24–34; Shimada et al., 2011, p. 158–177, Fig. 3–4, Appendix 2, Meristogenys amoropalamus (larval morphotype 3 -a): Shimada et al., 2007 b, p. 59–63. Diagnosis. This species is a member of the genus Meristogenys, based on the morphology of the larval specimens molecularly assigned to it (larval morphotype 3 -a in Shimada et al., 2007 a); these had diagnostic characteristics of the genus: abdominal sucker; divided upper jaw sheaths; and ribs on the outer surface of both jaw sheaths. Meristogenys dyscritus is a small species of the M. jerboa species group (Matsui, 1986), with male SVL 31.7–39.5 mm, female SVL 61.0– 71.2 mm; rear of thigh dark brown, dusted with small irregular light spots; web poorly developed leaving terminal two phalanges on fourth toe free of broad webbing; ova relatively small and heavily pigmented in the animal pole; upper third of iris sandy brown to yellowish brown. Etymology. The specific name is derived from dyskritos (Gr.), doubtful or indistinguishable, referring that the new species is difficult to distinguish from M. amoropalamus in adult morphology. Holotype. Osaka Museum of Natural History (OMNH) Am 8069, an adult male from Liwagu River, 1500 m, Headquarters of Kinabalu National Park, Sabah, Malaysia. Collected in March, 1979, by Masafumi Matsui. Paratypes. Two males and a female from the type locality; Zoologisches Forschungsinstitut und Museum A. Koenig, Bonn (ZFMK) 41644; Sabah Parks (SP) 26481, 21392. Referred specimens. Forty-five males and 16 females from the type locality (Liwagu), Mahua, and Wario (See Appendix). Description of Holotype (measurements in mm). Body moderately slender, SVL 31.7; head subtriangular, slightly longer (12.8) than wide (12.7); snout blunt, projecting slightly beyond lower jaw; eyes elevated; canthi sharp, slightly concave; lores slightly oblique, concave; nostrils lateral, just below canthal edge, distinctly closer to tip of snout (2.4) than to eye (2.7); IND (4.3) wider than IOD (3.0); latter narrower than UEW (3.4); SL 5.2; pineal spot visible, slightly behind the line connecting anterior corners of orbits; tympanum distinct, TDv (3.5) and TDh (3.4), two-thirds of EL (5.2); T-EL (0.8) one-fourth of TDv and TDh; vomerine teeth obvious, in small oblique groups separated by the width of one group, groups on line connecting rear rims of choanae; tongue deeply notched, without papilla; paired subgular vocal sacs form gular pouches at corners of throat; vocal opening just inside commissures of jaws. Fingers slender, first and second subequal, much shorter than third; tips expanded into disks having circummarginal grooves; disks of all fingers subequal in diameter, one-third diameter of tympanum; no fringes of skin along fingers; no supernumerary metacarpal tubercles; distinct nuptial pads covering dorsal and medial surfaces of the first finger from its base to subarticular tubercle. Forelimb length unavailable; LAL 19.1; HAL 11.0; HLL 69.7; tibia long (23.1); heels overlapping when limbs are held at right angles to body; THIGH (19.9) and FL (20.3) much shorter than TL. Toe disks similar to those of fingers in shape and size; webbing not fully extending to disk on fourth toe, leaving two phalanges free of broad sheet; excision of web between fourth and fifth toes proximal to middle subarticular tubercle of fourth toe; a narrow fringe of skin along medial edge of first toe; inner metatarsal tubercle elliptical, shorter than distance between it and subarticular tubercle of first toe; a small round, raised outer metatarsal tubercle. Skin of dorsum finely granular on head and trunk; a weak fold from above eye to axilla; a low dorsolateral glandular fold; side of trunk coarsely granular; limbs strongly rugose above; throat smooth; chest and abdomen weakly rugose. Colour in life (See coloured pictures of Fig. 7). Dorsum light brown with small dark spots; lores with dark streak below canthus; upper lip light grey; a blackish brown band beginning behind eye bordering rear of the tympanum, diverging above the tympanum and nearly reaching the inguinal area, dorsal and ventral boundaries sharp; limbs marked dorsally with alternating light and dark brown crossbars, the darker ones narrower; a short dark streak ventrally at insertion of arm; rear of thigh light brown with scattered irregular light spots; throat and chest whitish with dots of melanophores; lower lip vaguely barred with blackish brown; ventral surface of tibia whitish, with heavy pigmentation of melanophores. Iris colour. Although iris colour of the holotype is unavailable, other specimens from the type locality (Liwagu) had the bicoloured iris, sandy brown above and reddish brown below. Colour in alcohol. Color pattern has not been changed even after preservation in ethanol for several years, except for iris colour which disappeared soon after the fixation in formalin solution. Eggs: Ova bicoloured, heavy pigmentations on the animal pole, cream white on the vegetal pole; clutch size 750–1500; ovum diameter 1.6–1.8 mm. Larvae (See coloured pictures of Fig. 8): We examined 67 specimens of stage 26–41 of Gosner (1960) from Mahua. These specimens are identical to those used by Shimada et al. (2007 a) to define their larval morphotype 3 - a. Head-body length (HBL) 10.0– 16.8 mm. Head-body oval, broadly rounded at snout, flat below, head-body width (HBW) maximum at level of spiracle 61–71 % (median= 65.8 %) of HBL; depth 49–64 % (median= 55.4 %) of HBW; eyes dorsolateral, not visible from below, pointing outward, eyeball 13–15 % (median= 13.7 %) of HBL; interorbital 123–169 % (median= 147.6 %) of eye diameter; eye-snout distance 36–46 % (median= 41.1 %) of HBL; nostril open, rim not raised, closer to eye than to tip of snout; internarial 57–80 % (median= 69.8 %) of interorbital. Oral disk ventral, width 57–73 % (median= 65.7 %) of HBW; upper lip separated from snout by a groove; upper lip with short marginal papillae in lateral third, inframarginal papillae near corner; lower lip with uninterrupted row of short marginal papillae; labial tooth row formulae 6 (4–6)/ 6 (1) in three specimens, 6 (4–6)/ 7 (1) in 48 specimens, and 6 (4–6)/ 8 (1) in 13 specimens; jaw sheaths heavy completely black except for outer margins covered by thin film; upper sheath film thicker than the lower; outer surface of lower jaw sheaths with several weak ribs; margin finely serrate, 3–11 and 4–7 serrae on a half of upper and lower jaw sheaths, respectively; upper jaw sheaths Mshaped, lower V-shaped; both jaw sheaths divided; a large suctorial abdominal disk following oral disk; peripheral part of disk darkened and keratinized; length 40–52 % (median= 46.5 %) of HBL; width 78–98 % (median= 87.9 %) of HBW. Spiracle sinistral; tube moderately long, length subequal to length of eyeball, pointing upward and backward, free of body wall for half its length; anal tube median, free of tail; tail heavily muscled, dorsal margin strongly convex, deepest before middle, tapering to slightly pointed tip; tail length 143–179 % (median= 164.7 %) of HBL, maximum depth 23–33 % (median= 26.5 %) of length; caudal muscle deeper than fins in basal half; dorsal fin origin behind body, fin deeper than ventral fin except in final fourth; ventral fin origin at end of proximal third of tail; head-body with four pairs of glandular clusters; a postorbital cluster about an eye length behind eye, with 0–3 glands; a infraorbital at the base of snout, with 1–3 glands; a prespiracular cluster just anterior to spiracle, with 0–4 glands; a midlateral at the posterior end of body, with 0–8 glands; no ventral and dorsal fin glands; 0–16 ventral fin glands; head-body scattered dorsally with minute protuberances anterior to eye in developed larvae; the area occupied by spinules and their density increasing with stage of development; lateral line pores indistinct. Head-body light brown dorsally and laterally, sometimes posterior half of lateral surface dark brown; caudal muscle light brown; translucent fins with scattered pigmentations. Other ten larval specimens from Bundu Tuhan (st. 28), Liwagu (st. 32), Poring (st. 31), and Wario (st. 30 and 32) had characteristics similar to Mahua specimens, but all ten specimens had six rows of lower labial teeth. Variation. Males from Mahua tended to be smaller than males from Liwagu and Wario in SVL (Table 3). Although relatively weak web development is one of the diagnostic characters of this species, some females from Liwagu and Wario had developed broad webs, which reached to the toe disk. Individuals usually had a bicoloured iris, sandy brown above and reddish brown below, but some females from Liwagu had monocoloured reddish brown iris. Larvae from Mt. Kinabalu tended to have fewer labial tooth rows in lower jaw than the specimens from Mahua (Crocker Range). In Mahua, only 4.7 % of larvae had six rows of labial teeth on the lower jaw, and all other larvae had seven or eight rows, whereas all ten larvae collected around Mt. Kinabalu (Bundu Tuhan, Liwagu, Poring and Wario) had six rows. Calls. We recorded calls of a male of M. dyscritus (SP 26472) at Liwagu at the midnight of 14 June 2007 (Fig. 9) at an air temperature of 17.5 C. The male perched on a low shrub, 50 cm above ground, and 1 m from the river. Many other males were also calling around there. The call was emitted sporadically with several minutes intervals, and consisted of a short, unpulsed note, lasting about 0.11 sec. A call included three continuous phases, of which the first one had a marked frequency modulation; it descended quickly in frequency from 8000–10000 Hz down to about 6000 Hz. In the second phase, the frequency was kept stable around 6000 Hz. The third phase had a remarkable frequency modulation again; it ascended quickly in frequency from 6000 up to 9000 Hz. Dominant frequencies were traced at about 6000–10000 Hz ranges, and harmonic bands were often found between 12000–15000 Hz ranges. Comparisons. Among 11 known species of Meristogenys, M. kinabaluensis (Inger, 1966), M. poecilus (Inger and Gritis, 1983), M. stenocephalus Shimada et al. 2011, M. stigmachilus Shimada et al. 2011, and M. whiteheadi (Boulenger, 1887) have a large body size (male SVL> 45 mm, female SVL> 70 mm) and are easily distinguished from M. dyscritus. From some small species, M. dyscritus is differentiated in the poorly developed toe webs [In M. jerboa (Gunther, 1872), M. macrophthalmus (Matsui, 1986), M. maryatiae Matsui et al., 2008, M. orphnocnemis (Matsui, 1986), and M. phaeomerus (Inger and Gritis, 1983), webs reach at the toe disk], heavy pigmentations on the ventral surface of tibia (M. jerboa, M. maryatiae, M. orphnocnemis, and M. phaeomerus have only scattered pigmentation), small irregular light spots on the rear of thigh (M. jerboa and M. macrophthalmus have large bright blotches), and black streaks around eyes, lores and tympanum (M. jerboa, M. maryatiae, M. orphnocnemis, and M. phaeomerus usually lack such colour patterns). Meristogenys dyscritus resembles M. amoropalamus in adult morphology, but the typical individuals can be identified through morphological characters. The upper iris of M. dyscritus is usually sandy brown, but is yellowish green in M. amoropalamus (Fig. 6), although this character changes after anaesthesia, and there might be an intraspecific variation. Additionally, females of M. dyscritus have smaller (Fig. 5) ova and larger clutch size (Fig. 4) than M. amoropalamus (See “Reproductive characters” in Result). In females, M. dyscritus have longer hand (usually longer than 31 % of SVL) than M. amoropalamus (usually less than 31 % of SVL) (Fig. 10). Males of M. amoropalamus usually have larger tympanum (more than 13 mm 2) than those of M. dyscritus (less than 15 mm 2), although there is a range of overlap (Fig 11). Contrary to the adult morphology, the larvae of M. dyscritus is quite different from those of M. amoropalamus in morphological characters. The larvae of M. dyscritus have six rows on upper jaws, while those of M. amoropalamus have seven. In the young developmental stages, the lower jaw sheaths of both larvae is divided, but only those of M. amoropalamus fuse into a large single jaw sheath before metamorphosis. Glands in a tail are limited to ventral fin in larval M. dyscritus, while they are present in both fins of larval M. amoropalamus. For the comparison between larval M. dyscritus and other Meristogenys larvae in Sabah, see the KEY TO MERISTOGENYS LAR- VAE FROM SABAH. The larvae of M. dyscritus share divided lower jaw sheaths, six rows of labial teeth on the upper jaw, and no glands on their dorsal fin or ventral surface with larval M. orphnocnemis. The larvae of M. dyscritus, however, have rectangular body shape (body oval in M. orphnocnemis), surface projections restricted to head (projections on head and body in advanced stage in M. orphnocnemis), and usually seven or eight rows of lower labial teeth (usually six rows in M. orphnocnemis; See Shimada et al., 2007 a for details). Range. Besides the type locality Liwagu, 1500 m a.s.l., adults of this species have been collected from Wario (900 m a.s.l.) in the Kinabalu National Park, and Mahua (1063 m a.s.l.) in the Crocker Range National Park, all in Sabah, Malaysia. The larvae of this species have also been collected from Bundu Tuhan (990 m a.s.l.) and Poring (500 m a.s.l.) in/around the Kinabalu National Park. Natural history. Gravid females were collected in July (Liwagu), August (Mahua and Wario), November (Wario), and December (Mahua). Larvae collected in March (Liwagu and Mahua), August (Liwagu, Wario, Bundu Tuhan, and Mahua), and November (Poring) showed a wide range of developmental stages. Thus, there seems to be no particular reproductive seasons. Larvae were collected from rivers with a width of 5– 10 m. At night, they make a mixed cluster with larvae of M. kinabaluensis, M. orphnocnemis, and Huia cavitympanum on top of flat rocks in the river.Published as part of Shimada, Tomohiko, Matsui, Masafumi, Yambun, Paul & Sudin, Ahmad, 2011, A survey of morphological variation in adult Meristogenys amoropalamus (Amphibia, Anura, Ranidae), with a description of a new cryptic species, pp. 33-56 in Zootaxa 2905 on pages 42-50, DOI: 10.5281/zenodo.20559
Shimada Seamount: An example of recent mid-plate volcanism
No full textShimada Seamount is an isolated volcanic feature located between the Clipperton and Clarion Fracture Zones ∼1,150 km west of the East Pacific Rise and ∼600 km west of the inactive spreading center represented by the Mathematician Seamounts. It rises ∼3,900 m above the surrounding sea floor to within 50 m of present-day sea level. The area of Shimada Seamount should be volcanically dormant, because it is far from an active spreading center and is located on oceanic crust of early Miocene age. Nevertheless, evidence was found that Shimada Seamount has formed geologically recently. For example, seismic-reflection profiles-indicate that virtually no sediment has accumulated on the summit or flanks of the seamount; television, still-camera, and dredge-haul data indicate that a platform near the summit at a water depth of ∼180 m is a carbonate build-up formed by coralline red algae attached to fresh pillow basalt. Glassy pillow basalt too young to date by the K/Ar method and showing little or no devitrification and lacking manganese encrustations was dredged from the seamount below the algal reefs (500–750 m). Several cores taken from the adjacent basin (∼3,900 m deep) contain fresh glassy basalt detritus, and one core sampled a thin flow of unaltered basaltic glass at the sediment surface.
The origin and history of Shimada Seamount differ importantly from volcanoes generally thought to form at spreading centers, along transform faults, or at hot spots. The existence of Shimada Seamount, therefore, has implications about tectonic processes that occur in interplate regions
Three-dimensional numerical analysis of switching properties of high-speed and non-volatile nanoelectromechanical memory
No full textPhanodermopsis dordi Shimada & Takeda & Tsune & Murakami 2020, sp. nov.
No full textPhanodermopsis dordi Shimada, sp. nov. Figures 1–2, Table 4. Type material. Holotype. Adult male (NSMT-As 4617), formalin-fixed, permanent whole mount, broken in posterior body region and connected with vas deferens (see Figures 1, 2). Type locality. CCFZ (10° 25.9376′ N, 147° 50.0029′ W, 5321 m depth) with a spade corer by the third author on 1 Oct. 2016. Diagnosis. Phanodermopsis dordi sp. nov. is characterized by the papilliform outer labial and cephalic sensilla, the absence of the sub-cephalic sensilla, the anterior position of the pore of secretory-excretory system (1.4 cephalic diameters from anterior body end), the long, conical tail (2.3 cloacal body diameters) with an acute tip, the long spicules (1.9 cloacal body diameters), and the absence of the gubernaculum. Etymology. The specific name dordi is a noun in the genitive case after DORD. Description. Male. Body almost cylindrical, tapering toward both ends. Cuticle finely striated, 2–5 μm thick. Somatic sensilla absent. Gland cells surrounding intestine (cf. Shimada & Kakui 2019) absent. Head rounded and slightly set off by constriction at 0.6 cephalic diameters from anterior body end, diameter at level of cephalic sensilla bases equal to 0.2 maximum body diameters. Cephalic cuticle 1–2 μm thick. Type II pharyngo-cephalic complex (cf. Zograf et al. 2015) present: pharyngeal capsule with three short outgrowths at anterior end; cephalic capsule weakly developed (ca. 1 μm thick and 6 μm long). Six inner labial sensilla papilliform. Six outer labial and four cephalic sensilla also papilliform, arranged in separate circles (the former just anterior to the latter), situated at 0.4 cephalic diameters from anterior end. Sub-cephalic or cervical sensilla absent. Amphids situated at 0.75 cephalic diameters from anterior end, 0.3 corresponding body diameters wide, with transverse slit-like aperture and pocket-like fovea. Buccal cavity conical, without solid teeth. Pharynx enlarged posteriorly. Pore of secretory-excretory system located at 1.4 cephalic diameters or 0.05 pharyngeal lengths from anterior end. Gland cell of secretory-excretory system not observed. Nerve ring at 0.45 pharyngeal lengths from anterior end. Cardia short, 1/3 of corresponding body diameters long. Intestine almost cylindrical, broken in posterior body region. Tail conical, 2.3 cloacal body diameters long. Cloacal or caudal sensilla not observed. Tail tip acute, with spinneret and no terminal setae. Caudal glands precloacal, but probably lost due to injury of posterior body region. Reproductive system diorchic. Testes opposed and outstretched, both located on left side of intestine: anterior testis longer, situated from 53% to 70% of body length; posterior testis situated from 68% to 74% of body length. Sperms globular or spheroid in shape, 3–10 μm in diameter. Vas deferens conspicuous. Spicules equal in size and shape, 1.9 cloacal body diameters long or 0.8 tail lengths, strongly arcuate, without proximal head, distally not acute. Gubernaculum not observed. Precloacal supplement or sensilla absent. Female. Not found. Remarks. A male was identified as a member of the genus Phanodermopsis based on the presence of the type II pharyngo-cephalic complex, the short spicule (less than 2.0 cloacal body diameters), and the absence of the precloacal supplement. Phanodermopsis contains only four valid species: P. groenlandica Ditlevsen, 1926, P. ingrami Mawson, 1958, P. kohtsukai Shimada & Kakui, 2019, and P. nana Zograf et al., 2015 (Zograf et al. 2015; Shimada & Kakui 2019). Phanodermopsis dordi sp. nov. differs from all the congeners by the papilliform outer labial and cephalic sensilla (vs. setiform, 0.5–1.0 cephalic body diameters long in the congeners); and the position of the pore of secretoryexcretory system (1.4 cephalic diameters from anterior body end in P. dordi sp. nov. vs. 2.8–4.6 in the congeners). Phanodermopsis dordi sp. nov. is also distinguished from P. groenlandica, P. ingrami, and P. nana by the conical tail (vs. conico-cylindrical with the short posterior portion in the latter three species) and from P. kohtsukai by the longer (2.3 cloacal body diameters) tail with acute tip (vs. 1.3 cloacal body diameters long with blunt tip in P. kohtsukai). In addition, P. dordi sp. nov. differs from P. ingrami by the longer spicules (1.9 cloacal body diameters in P. dordi sp. nov. vs. shorter than 1.0 cloacal body diameters in P. ingrami), from P. nana by the absence of the gubernaculum (vs. present in P. nana), and from P. kohtsukai by the absence of the sub-cephalic sensilla (vs. four sub-cephalic setae present in P. kohtsukai). The taxonomic key for the species of Phanodermopsis is as follows: 1 Outer labial and cephalic sensilla papilliform................................................... P. dordi sp. nov. - Outer labial and cephalic sensilla setiform.................................................................. 2 2 Cephalic setae equal to cephalic diameter............................................................. P. nana - Cephalic setae equal to or shorter than a half of cephalic diameter............................................... 3 3 Tail conical................................................................................. P. kohtsukai - Tail conico-cylindrical................................................................................. 4 4 Tail ca. 2.5 cloacal or anal body diameters in males, 2.0 in females....................................... P. ingrami - Tail shorter than 1.5 anal body diameters........................................................ P. groenlandicaPublished as part of Shimada, Daisuke, Takeda, Naoya, Tsune, Akira & Murakami, Chisato, 2020, Three new species of free-living marine nematodes (Nematoda: Enoplida) from the Clarion-Clipperton Fracture Zone (CCFZ), North Pacific, pp. 507-526 in Zootaxa 4859 (4) on pages 510-513, DOI: 10.11646/zootaxa.4859.4.3, http://zenodo.org/record/453729
Chlorophyll and phaeopigment data collected off the Oregon Coast on two cruises aboard NOAA Ship Bell M. Shimada during 2018
No full textDataset: Chlorophyll and PhaeopigmentChlorophyll and phaeopigment data collected off the Oregon Coast on two cruises aboard NOAA Ship Bell M. Shimada during 2018.
For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/837587NSF Division of Ocean Sciences (NSF OCE) OCE-183849
Pyrosome abundances from samples collected off the Oregon Coast on three cruises aboard NOAA Ship Bell M. Shimada during 2018
No full textDataset: Pyrosome AbundancesPyrosome abundances from samples collected off the Oregon Coast on three cruises aboard NOAA Ship Bell M. Shimada during 2018.
For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/837652NSF Division of Ocean Sciences (NSF OCE) OCE-183849
CTD data collected off the Oregon Coast on three cruises aboard NOAA Ship Bell M. Shimada during 2018
No full textDataset: CTDCTD data collected off the Oregon Coast on three cruises aboard NOAA Ship Bell M. Shimada during 2018.
For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/837256NSF Division of Ocean Sciences (NSF OCE) OCE-183849
Trichonotus elegans Shimada & Yoshino 1984
No full textTrichonotus elegans Shimada & Yoshino 1984 —Elegant sand-diver Status at New Ireland. New record, based on specimens photographed at Lissenung Island by Dietmar Amon on 27 May 2007, and at 10 m depth by Dean Tully on 19 Sept. 2015. Distribution and habitat. New Ireland: 2.—General distribution: Maldives east to Marshall Islands and Fiji, north to Ryukyu Islands, south to New Guinea. Sand and rubble bottoms, 1–40 m depth. Marine.Published as part of Andréfouët, Serge, Chen, Wei-Jen, Kinch, Jeff, Mana, Ralph, Russell, Barry C., Tully, Dean & White, William T., 2019, Checklist of the marine and estuarine fishes of New Ireland Province, Papua New Guinea, western Pacific Ocean, with 810 new records, pp. 1-360 in Zootaxa 4588 (1) on page 250, DOI: 10.11646/zootaxa.4588.1.1, http://zenodo.org/record/298816
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