﻿Distribution of Stenasellidae in Africa and description of a new species of Metastenasellus from Cameroonian groundwaters

Pountougnigni Oumarou Farikou,Zebaze Togouet Serge Hubert,Sob Nangou Paul Bertrand,Piscart Christophe

doi:10.3897/subtbiol.40.76301

Distribution of Stenasellidae in Africa and description of a new species of Metastenasellus from Cameroonian groundwaters

Pountougnigni Oumarou Farikou, Zebaze Togouet Serge Hubert + Show 2 more

Open Access

https://doi.org/10.3897/subtbiol.40.76301

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Abstract

During recent investigations of the groundwater fauna of Cameroon, specimens of a new species of the stygobitic genus Metastenasellus, M. boutini sp. nov. were collected in wells of the city of Douala. The new species can be easily distinguished from the other species of the genus by its relatively large size (up to 11 mm), pleonite 1 and 2 half the length of pereonite 7, the shape of pleopod 2 in males (presence of an external lobe on the protopodite, distal part of the spermatic duct slightly protruding out of the second article, lack of a distal seta on the exopodite), and uropod half the length of the pleotelson. Ecological data and a key to Metastenasellus species are provided. We also performed an exhaustive analysis of the literature on Stenasellidae in Africa to study the geographical distribution of the family in this continent and discuss some hypotheses about the origin of African species.

Highlights

Over the last decades, investigations of groundwaters around the world have highlighted an unexpectedly high diversity of organisms forming the so-called stygobitic fauna
More recent discoveries of new species in western, central, and eastern Africa have modified the taxonomy of the family in-depth, with the description of seven new genera since 1966 and especially the genus Metastenasellus (Magniez 1966)
Magniez originally defined this genus as displaying well-developed pleonites 1 and 2, dactyli of pereopods 2–7 with one sternal spine, the male protopodite of pleopod 1 without a coupling hook and the male endopodite of pleopod 2 very voluminous and a helicoidal spermatic duct

Summary

Introduction

Investigations of groundwaters around the world have highlighted an unexpectedly high diversity of organisms forming the so-called stygobitic fauna. Stygobitic diversity even exceeds epigean diversity for some groups (Stoch 1995; Sket 1999; Gibert and Culver 2009) This is the case for freshwater crustaceans; for instance, 38% of known freshwater species in Europe live only in groundwaters (Sket 1999). Despite important progress in our knowledge of groundwater biodiversity, data from the different parts of the world are still heterogeneous, with very poorly known regions (Gibert and Culver 2009) This is true for continental Africa, where data about the diversity and distribution of the stygobites are scarce (Tuekam Kayo et al 2012) and mainly reported in a few taxonomic papers. Stenasellidae harbors the highest number of species, with 23 currently known species distributed into 6 genera

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