Local Hotspots of Endemism or Artifacts of Incorrect Taxonomy? The Status of Microendemic Pill Millipede Species of the Genus Glomeris in Northern Italy (Diplopoda, Glomerida)

Abstract

Local endemic species with their unique evolutionary history always stirred the interest of scientists. One such area especially rich in endemics is northern Italy. In case of pill millipedes of the genus Glomeris Latreille, 1803, only a single species is found in northern Europe, while 22 country-endemics alone are known from Italy. Many of these endemics, however, have not been studied in several decades; therefore we aimed to determine whether this diversity is the result of overlooked synonymies or natural processes. A focus was placed on the local endemics that are in some aspects morphologically similar to the widespread and variable G. klugii Brandt, 1833. The local endemics Glomeris larii Verhoeff, 1921, G. primordialis Verhoeff, 1930, G. oblongoguttata Verhoeff, 1894, G. oropensis Verhoeff, 1936, G. transalpina Koch, 1836, G. romana Verhoeff, 1900, G. ligurica Latzel, 1884 and G. apuana Verhoeff, 1911 were included in a molecular analysis incorporating ribosomal nuclear (28S) and mitochondrial (COI) genes. Individuals were sequenced and compared to 31 specimens from 18 localities of G. klugii. The final dataset included 657 base pairs for 56 terminals in the COI, and 14 terminals with 1068 base pairs in the combined 28S and COI analysis. Our analysis shows intraspecific distances of up to 5% in the COI gene in G. klugii that are not strictly correlated to geography or color pattern. G. larii is discovered to be genetically and morphologically identical to G. klugii and is synonymised with the latter. Interspecific distances in our dataset vary between 6.7 to 15.9%, with the lowest (6.7–9.0%) between G. primordialis and G. klugii. Our analysis confirms the species status of the local endemics G. primordialis, G. oblongoguttata, G. oropensis, G. transalpina, G. ligurica and G. apuana. We also confirm the synonymy of G. undulata Koch, 1844 under G. klugii. G. genuensis Latzel, 1886 is indistinguishable from G. ligurica.

An integrative and citizen science based approach to the rediscovery and redescription of the only known high-altitude endemic Pill Millipede, Glomeris aurita Koch (Diplopoda, Glomerida)

“…In addition, some other morphological characters used to separate these species by Verhoeff, such as an incomplete second stria on the collum, varies strongly within the here studied G. aurita specimens. Our studies ( Wesener, 2015b ; Wesener & Conrad, 2016 ; this study) confirm that only new collections of these species and subsequent molecular studies will be able to solve the mysteries surroundings the high number of local endemic pill millipedes in northern Italy.…”

“…Given the known isolation of well-researched Monte Baldo during the last Ice Age, it might be possible to date the observed genetic distances of the Monte Baldo population to those of other populations. This dating might allow a more precise dating of the speciation events of the genus Glomeris in northern Italy and beyond to finally gain a better understanding of the pill millipede microendemism so prevalent in the area ( Wesener & Conrad, 2016 ).…”

“…One of these ‘forgotten’ species, G. apuana Verhoeff, 1911 was revised with the help of barcode data ( Wesener, 2015b ). Additionally, a recent integrative revision investigated four endemics, G. oropensis Verhoeff, 1934 , G. primordialis Verhoeff, 1932 , G. oblongoguttata Verhoeff, 1894 and G. larii Verhoeff, 1921 belonging to the Glomeris klugii species-group, and discovered G. larii as a synonym ( Wesener & Conrad, 2016 ).…”

Intraspecific variation and phylogeography of the millipede model organism, the Black Pill Millipede Glomeris marginata (Villers, 1789) (Diplopoda, Glomerida, Glomeridae)

“…In comparison to vertebrate species (e.g., fishes: 0.32 %, Keskin and Atar 2013 or rodents: 2.1 %, Li et al 2015) a maximum intraspecific variation of a p-distance of 5 % is rather high. However, such an intraspecific variation of 5 % was also found in another widespread central European Glomeris , G.klugii/undulata (Wesener and Conrad 2016). A minimum p-distance of 12.9 % of G.marginata to the most closely related species (a factor of 2.6 to the maximum intraspecific p-distance), shows a clear barcoding gap to the nearest congener, G.connexa .…”

Phylogeography and DNA-based species delimitation provide insight into the taxonomy of the polymorphic rose chafer Protaetia (Potosia) cuprea species complex (Coleoptera: Scarabaeidae: Cetoniinae) in the Western Palearctic

“…It has been repeatedly demonstrated that DNA sequences provide a powerful tool for the recognition of phylogenetic patterns within a species complex (e.g. [ 1 – 4 ]) which is essential for the reconstruction of their range evolution (phylogeography) and for defining potential conservation units [ 5 ]. Propelled by an easy DNA data acquisition, this approach has led to a renaissance of its use for taxonomic hypothesis testing in a number of insect species (e.g.…”