International Society for Diatom Research
  • Home
  • About
    • About ISDR
    • Council Members
    • Society People
    • Diatom Research
    • Contact Us
  • Membership
  • ISDR Meetings
  • Announcements
    • News
    • Meetings
    • Opportunities
    • Networking
  • Diatom Of The Month
    • About
    • DOM
  • Young ISDR
    • About
    • Young ISDR Blog
  • Log in
Select Page

DIATOM RESEARCH: On the enigmatic diatom Rhizosolenia dubia, its relationship to Pseudopyxilla and Proboscia, and description of a new species, Proboscia pinocchioi sp. nov.

by Abe and Jordan |

Pyxilla? dubia was originally described from Jutland, but subsequently transferred to Pseudopyxilla. However, the discovery, over eighty years apart, of two enigmatic specimens with tubular heterovalvate frustules featuring a Pseudopyxilla dubia valve at one end and a rhizosolenioid valve at the other end resulted in a new combination, Rhizosolenia dubia. Herein, we document in detail the valve morphology of specimens observed in early Eocene samples from Mors (Jutland) using light and scanning electron microscopy. Our results reveal the presence of both valve types (but never as heterovalvate frustules). The rhizosolenioid valves possess a proboscis with three spinulae at the tip (the middle one being very extensive), a longitudinal slit on the dorsal side, and claspers on the basal part of the domed valve on the ventral side. Our results suggest that the Pseudopyxilla frustule is the resting spore of a yet, unknown diatom, while the ‘rhizosolenioid’ valve represents the vegetative phase of a new species, Proboscia pinocchioi sp. nov. From an evolutionary standpoint, P. pinocchioi lacks the longitudinal ridges of the cretacea lineage, but bears the characteristic polar spinulae and limited pore distribution of the barboi lineage. However, P. pinocchioi surprisingly possesses claspers (normally observed only in the alata lineage) – representing the oldest evidence of claspers in rhizosolenioid diatoms.

 

Kenta Abe & Richard W. Jordan (2023) On the enigmatic diatom Rhizosolenia dubia, its relationship to Pseudopyxilla and Proboscia, and description of a new species, Proboscia pinocchioi sp. nov., Diatom Research, DOI: 10.1080/0269249X.2022.2154280



    Get In Touch

    If you’d like to know more, please contact us to get involved and learn about diatom research around the world.

    Contact ISDR

    • facebook
    • twitter

    ISDR Mission

    The International Society for Diatom Research promotes fundamental diatom research and translation of that research for public benefit throughout the world.

    The International Society for Diatom Research

    Society Details

    secretary@isdr.org
    president@isdr.org
    treasurer@isdr.org
    editor@isdr.org
    webmaster@isdr.org
    youngISDR@isdr.org

    Registered Charity (1054897)

    ISDR Constitution
    Privacy Policy

    Copyright 2023 © The International Society For Diatom Research | Site design by The Big Idea