Actinocyclus nipponicus sp. nov. and A. bradburyii sp. nov. (Bacillariophyta) from Miocene lacustrine sediments of the proto-Japan Sea

Tatsuya Hayashi, Megumi Saito-Kato, Yoshihiro Tanimura

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

Fossil nonmarine Actinocyclus species, A. nipponicus sp. nov. and A. bradburyii sp. nov., are described from Miocene lake sediments in the Yamato Bank, the central part of the Japan Sea. Actinocyclus nipponicus is characterized by an inflated valve composed of a nearly flat valve face and an inclined mantle, a bullulate valve wall, fascicles sectioned by combinations of independent areola rows and hyaline stripes, loculate areolae with external cribra, rimoportulae at ends of hyaline stripes in the mantle, a single pseudonodulus at the valve face/mantle junction and well-developed spines. On the other hand, A. bradburyii is characterized by a noninflated valve composed of a nearly flat valve face and a very gently inclined mantle, a bullulate valve wall, loculate areolae with external cribra, fascicles sectioned by combinations of independent areola rows and hyaline stripes, rimoportulae at ends of hyaline stripes in the mantle, a single pseudonodulus within the valve face and misshapen cribra behind the pseudonodulus. In A. nipponicus, fascicles are composed of parallel areola rows in large valves, but are composed of radial areola rows in small valves. Additionally, in both A. nipponicus and A. bradburyii, changes in the number of rimoportulae (fascicles) occur as a function of valve size. Actinocyclus nipponicus and A. bradburyii are the most similar to A. trapeziformis and A. cupreus, respectively.

Original languageEnglish
Pages (from-to)98-112
Number of pages15
JournalPhycologia
Volume51
Issue number1
DOIs
Publication statusPublished - Jan 31 2012
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Aquatic Science
  • Plant Science

Fingerprint Dive into the research topics of 'Actinocyclus nipponicus sp. nov. and A. bradburyii sp. nov. (Bacillariophyta) from Miocene lacustrine sediments of the proto-Japan Sea'. Together they form a unique fingerprint.

Cite this