Groping through the black box of variability: An integrative taxonomic and nomenclatural re-evaluation of Zospeum isselianum Pollonera, 1887 and allied species using new imaging technology (Nano-CT, SEM), conchological, histological and molecular data (Ellobioidea, Carychiidae)

By

Jochum, Adrienne
Slapnik, Rajko
Klussmann-Kolb, Annette 1969-
Páll-Gergely, Barna
Kampschulte, Marian
Martels, Gunhild
Vrabec, Marko
Nesselhauf, Claudia
Weigand, Alexander M., 1984-

Type

Article

Date of Publication

2015

Original Publication

Subterranean Biology

Volume

16

Pages

123-165

Subjects

Byne’s degradation , lumped species , Neotypification , species flock , subterranean microgastropods

Contributed by

Pensoft Publishers

Language

English

Published by

Sofia, Bulgaria Pensoft Publishers

Identifiers

DOI: https://doi.org/10.3897/subtbiol.16.5758

 

Abstract

The minute troglobitic species, Zospeum isselianum Pollonera, 1887 (Eupulmonata: Ellobioidea, Carychiidae) is widely distributed within its Southern Alpine-Dinaric range. Its broad distribution and highly variable shell has caused this species to be historically lumped into its current taxonomic state of ambiguity. In an integrative taxonomic approach, phenotypic and genotypic data are synthesized to assess the intraspecific variability recently inferred for this taxon. We collected 16 Zospeum specimens in the Slovenian Alpine Arc encompassing the type locality for Z. isselianum. The material comprises five morphologically recognized (sub)species. The species are re-evaluated using SEM, X-ray nanotomography (nano-CT), conchological, histological and molecular data. Four well-defined lineages are present, which can be attributed to i) Z. isselianum s.str. from its new type locality (Turjeva jama), ii) a highly morphologically variable lineage that so far cannot be attributed to a single morphospecies, iii) Z. kupitzense A. Stummer, 1984 (raised to species rank) and iv) a lineage comprising the two subspecies Z. alpestre alpestre (Freyer, 1855) and Z. alpestre bolei Slapnik, 1991 plus Z. isselianum individuals. The latter is treated as a single taxon Z. alpestre. After considering the severely degraded syntype material of Zospeum isselianum, we provide a taxonomic re-description and propose a neotype for this species. Furthermore, new diagnostic information is revealed regarding the columella of Zospeum isselianum and allied species. Detailed anatomical study reveals new structural aspects of Zospeum morphology and provides groundwork for future investigations.