Taxonomic revision of the Afrotropical Agabus raffrayi species group with the description of four new species (Coleoptera, Dytiscidae)

We revise the Afrotropical Agabus raffrayi species group, motivated by the discovery of new diversity in Kenya and South Africa. Whilst Agabus is mainly a holarctic genus, the Agabus raffrayi group is restricted to high altitude regions of eastern Africa and temperate parts of South...

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Main Authors: William F. Englund, Laban Njoroge, Olof Biström, Kelly B. Miller, David T. Bilton, Johannes Bergsten
Format: Article
Language:English
Published: Pensoft Publishers 2020-08-01
Series:ZooKeys
Online Access:https://zookeys.pensoft.net/article/53470/download/pdf/
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spelling doaj-0d7ec01bb2464b4f96e18a230fdab5fd2020-11-25T03:54:24ZengPensoft PublishersZooKeys1313-29702020-08-01963457910.3897/zookeys.963.5347053470Taxonomic revision of the Afrotropical Agabus raffrayi species group with the description of four new species (Coleoptera, Dytiscidae)William F. Englund0Laban Njoroge1Olof Biström2Kelly B. Miller3David T. Bilton4Johannes Bergsten5Swedish Museum of Natural HistoryNational Museums of KenyaFinnish Museum of Natural HistoryUniversity of New MexicoUniversity of JohannesburgSwedish Museum of Natural History We revise the Afrotropical Agabus raffrayi species group, motivated by the discovery of new diversity in Kenya and South Africa. Whilst Agabus is mainly a holarctic genus, the Agabus raffrayi group is restricted to high altitude regions of eastern Africa and temperate parts of South Africa, from where we describe the southernmost Agabus in the world. The following new species are introduced: Agabus anguluverpus sp. nov. from Mount Kenya in central Kenya, Agabus austellus sp. nov. a widespread species in South Africa, Agabus riberae sp. nov. from the Kamiesberg and northeastern Cederberg ranges in the Northern and Western Cape Provinces of South Africa and Agabus agulhas sp. nov. from the Agulhas Plain, Western Cape Province, South Africa. We provide a distribution map, a determination key for males, quantitative measurements of diagnostic characters, habitus photos and detailed photos of male genitalia for all described species in the group, as well as images of diagnostic characters and habitats. The presence or absence of an elongated section between the subapical broadening and the base of the apical and subapical teeth of the male aedeagus is a useful novel character, first revealed by our study. In contrast with the most recent revision of Afrotropical Agabus, we show that Agabus ruwenzoricus Guignot, 1936 is restricted to eastern Africa; South African records of this species having been based on misidentifications, no species of the group being common to southern and eastern Africa. We speculate that the raffrayi group may display phylogenetic niche conservatism, being restricted, as an originally temperate taxon, to higher elevations in tropical eastern Africa, but occurring at lower altitudes in temperate South Africa. https://zookeys.pensoft.net/article/53470/download/pdf/
collection DOAJ
language English
format Article
sources DOAJ
author William F. Englund
Laban Njoroge
Olof Biström
Kelly B. Miller
David T. Bilton
Johannes Bergsten
spellingShingle William F. Englund
Laban Njoroge
Olof Biström
Kelly B. Miller
David T. Bilton
Johannes Bergsten
Taxonomic revision of the Afrotropical Agabus raffrayi species group with the description of four new species (Coleoptera, Dytiscidae)
ZooKeys
author_facet William F. Englund
Laban Njoroge
Olof Biström
Kelly B. Miller
David T. Bilton
Johannes Bergsten
author_sort William F. Englund
title Taxonomic revision of the Afrotropical Agabus raffrayi species group with the description of four new species (Coleoptera, Dytiscidae)
title_short Taxonomic revision of the Afrotropical Agabus raffrayi species group with the description of four new species (Coleoptera, Dytiscidae)
title_full Taxonomic revision of the Afrotropical Agabus raffrayi species group with the description of four new species (Coleoptera, Dytiscidae)
title_fullStr Taxonomic revision of the Afrotropical Agabus raffrayi species group with the description of four new species (Coleoptera, Dytiscidae)
title_full_unstemmed Taxonomic revision of the Afrotropical Agabus raffrayi species group with the description of four new species (Coleoptera, Dytiscidae)
title_sort taxonomic revision of the afrotropical agabus raffrayi species group with the description of four new species (coleoptera, dytiscidae)
publisher Pensoft Publishers
series ZooKeys
issn 1313-2970
publishDate 2020-08-01
description We revise the Afrotropical Agabus raffrayi species group, motivated by the discovery of new diversity in Kenya and South Africa. Whilst Agabus is mainly a holarctic genus, the Agabus raffrayi group is restricted to high altitude regions of eastern Africa and temperate parts of South Africa, from where we describe the southernmost Agabus in the world. The following new species are introduced: Agabus anguluverpus sp. nov. from Mount Kenya in central Kenya, Agabus austellus sp. nov. a widespread species in South Africa, Agabus riberae sp. nov. from the Kamiesberg and northeastern Cederberg ranges in the Northern and Western Cape Provinces of South Africa and Agabus agulhas sp. nov. from the Agulhas Plain, Western Cape Province, South Africa. We provide a distribution map, a determination key for males, quantitative measurements of diagnostic characters, habitus photos and detailed photos of male genitalia for all described species in the group, as well as images of diagnostic characters and habitats. The presence or absence of an elongated section between the subapical broadening and the base of the apical and subapical teeth of the male aedeagus is a useful novel character, first revealed by our study. In contrast with the most recent revision of Afrotropical Agabus, we show that Agabus ruwenzoricus Guignot, 1936 is restricted to eastern Africa; South African records of this species having been based on misidentifications, no species of the group being common to southern and eastern Africa. We speculate that the raffrayi group may display phylogenetic niche conservatism, being restricted, as an originally temperate taxon, to higher elevations in tropical eastern Africa, but occurring at lower altitudes in temperate South Africa.
url https://zookeys.pensoft.net/article/53470/download/pdf/
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