Morphometric and physical characteristics distinguishing adult Patagonian lamprey, Geotria macrostoma from the pouched lamprey, Geotria australis

PLoS One. 2021 May 5;16(5):e0250601. doi: 10.1371/journal.pone.0250601. eCollection 2021.

Abstract

The pouched lamprey, Geotria australis Gray, 1851, has long been considered monotypic in the Geotriidae family with a wide southern temperate distribution across Australasia and South America. Recent studies have provided molecular and morphological evidence for a second Geotria species in South America; Geotria macrostoma (Burmeister, 1868). The aim of this study was to determine morphometric and physical characteristics of adult G. macrostoma that further differentiate this re-instated species of Geotriidae from G. australis. The diagnostic features discriminating immature adult G. macrostoma from G. australis when entering fresh water, are distinct differences in dentition, oral papillae and fimbriae counts and differences in coloration. In addition, G. macrostoma display greater growth of the prebranchial region and oral disc and has a deeper body depth and higher condition factor. All current ecological knowledge of the genus Geotria is based on Australasian populations, which may not be applicable to G. macrostoma. To ensure the conservation and protection of the Patagonian lamprey as a re-identified species, further investigations are needed to understand its life history, biology and ecology throughout its range.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Lampreys / anatomy & histology
  • Lampreys / classification*
  • Lampreys / physiology*
  • Physical Appearance, Body*
  • Rivers

Grants and funding

Authors from the National Institute of Water and Atmospheric Research Ltd and Kitson Consulting Ltd were funded by the New Zealand Ministry of Business Innovation and Employment (MBIE) contract CO1X1615. The funder provided support for the study design, data collection and analysis and preparation of the manuscript. The funder did not have any role in salaries for authors [CFB, PW, EW] but did partially cover salary for JK. The specific roles of these authors are articulated in the ‘author contributions’ section. Further funding was provided by IEASA (Integración Energética Argentina, www.ieasa.com.ar), Agencia Nacional de la Promoción de la Ciencia y la Tecnología (ANPCyT, Argentina, grant no. PICT2015-3490 to CRR, www.agencia.mincyt.gob.ar), CONICET (Consejo Nacional de Investigaciones Científicas y Técnicas, http://www.conicet.gov.ar), as well as a visiting professor grant in 2003 from MNHN (Paris) to CBR and a research grant in 2010 from the Canadian Museum of Nature to study at the NHM (London) to CBR.