Venus (Journal of the Malacological Society of Japan)
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Volume 74 , Issue 1-2
Showing 1-6 articles out of 6 articles from the selected issue
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Original Articles
  • Takenori Sasaki, Tomomi Ogura, Hiromi Kayama Watanabe, Katsunori Fujik ...
    Type: Original Article
    Volume 74 (2016) Issue 1-2 Pages 1-17
    Released: April 15, 2016
    JOURNALS OPEN ACCESS
    Members of the genus Provanna are abundant and widely distributed in deep-sea chemosynthetic environments. Around Japan provannids inhabit a wide range of depths and substrates. In this study, we report additional species of Provanna from vents and a seep in the Nansei-shoto area. Shell morphological and molecular phylogenetic analyses showed that there are four new species: (1) P. subglabra is characterized by an inflated smooth shell and is most abundant in vent fields in the Okinawa Trough; (2) P. clathrata has a roughly sculptured shell and is distributed in vents in the southern Okinawa Trough; (3) P. lucida possesses a thin smooth shell with a deep suture and is limited to vents on the Minami-Ensei Knoll in the northern Okinawa Trough; and (4) P. kuroshimensis, which is distinguished by an olive-colored periostracum and is endemic to a seep site on the Kuroshima Knoll. In contrast to shell and molecular characters, radula morphology does not show clear differences among these species. The present study revealed a high species diversity of Provanna in a relatively limited area in southwestern Japan. The diversification of the genus might be correlated with complex topographic features in the Nansei-shoto area including the Okinawa Trough and Ryukyu Arc.
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  • Taisei Nakayama, Kazunori Hasegawa
    Type: Original Article
    Volume 74 (2016) Issue 1-2 Pages 19-26
    Released: April 15, 2016
    JOURNALS OPEN ACCESS
    The northwestern Pacific species of the genus Epidendrium Gittenberger & Gittenberger, 2005, and those previously assigned to the genus Alora are reviewed based mainly on the conchological characters. The species previously identified as Alora billeeana (DuShane & Bratcher, 1965) in this area is correctly identified herein as E. aureum Gittenberger & Gittenberger, 2005, and another species in the genus, E. sordidum Gittenberger & Gittenberger, 2005, is recorded for the first time in the Japanese waters. Alora reticulata (Habe, 1962) is transferred to the genus Epidendrium, and an additional new species is described as E. parvitrochoides n. sp. from Japan. Alora annulata (Kuroda & Ito, 1961) is retained in the genus Alora following most recent works, and Alora kiiensis Nakayama, 2000 is transferred to the genus Tuba Lea, 1833 in the basal heterobranch family Mathildidae based on the characteristic heterostrophic protoconch and overall teleoconch features.
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  • Susumu Tomida, Yukio Sako
    Type: Original Article
    Volume 74 (2016) Issue 1-2 Pages 27-34
    Released: April 15, 2016
    JOURNALS OPEN ACCESS
    A new subspecies of Entemnotrochus rumphii (Schepman, 1879) from the middle Miocene Shikiya Formation, Kumano Group, at Uematsu, Kushimoto-cho, Higashimuro-gun, Wakayama Prefecture, central Japan is described herein as E. rumphii kushimotoensis n. subsp. This new subspecies is distinguished from E. rumphii rumphii by having a lower spire, a selenizone situated below mid-whorl and a larger number of spiral cords above the selenizone. Judging from the geographical distribution and the morphological affinities of the living E. rumphii rumphii, the new subspecies seems to be an ancestral form of the Recent species.
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Short Notes
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