Towards evidence-based conservation of subterranean ecosystems.

Subterranean ecosystems are among the most widespread environments on Earth, yet we still have poor knowledge of their biodiversity. To raise awareness of subterranean ecosystems, the essential services they provide, and their unique conservation challenges, 2021 and 2022 were designated International Years of Caves and Karst. As these ecosystems have traditionally been overlooked in global conservation agendas and multilateral agreements, a quantitative assessment of solution-based approaches to safeguard subterranean biota and associated habitats is timely. This assessment allows researchers and practitioners to understand the progress made and research needs in subterranean ecology and management. We conducted a systematic review of peer-reviewed and grey literature focused on subterranean ecosystems globally (terrestrial, freshwater, and saltwater systems), to quantify the available evidence-base for the effectiveness of conservation interventions. We selected 708 publications from the years 1964 to 2021 that discussed, recommended, or implemented 1,954 conservation interventions in subterranean ecosystems. We noted a steep increase in the number of studies from the 2000s while, surprisingly, the proportion of studies quantifying the impact of conservation interventions has steadily and significantly decreased in recent years. The effectiveness of 31% of conservation interventions has been tested statistically. We further highlight that 64% of the reported research occurred in the Palearctic and Nearctic biogeographic regions. Assessments of the effectiveness of conservation interventions were heavily biased towards indirect measures (monitoring and risk assessment), a limited sample of organisms (mostly arthropods and bats), and more accessible systems (terrestrial caves). Our results indicate that most conservation science in the field of subterranean biology does not apply a rigorous quantitative approach, resulting in sparse evidence for the effectiveness of interventions. This raises the important question of how to make conservation efforts more feasible to implement, cost-effective, and long-lasting. Although there is no single remedy, we propose a suite of potential solutions to focus our efforts better towards increasing statistical testing and stress the importance of standardising study reporting to facilitate meta-analytical exercises. We also provide a database summarising the available literature, which will help to build quantitative knowledge about interventions likely to yield the greatest impacts depending upon the subterranean species and habitats of interest. We view this as a starting point to shift away from the widespread tendency of recommending conservation interventions based on anecdotal and expert-based information rather than scientific evidence, without quantitatively testing their effectiveness.

New avatars for Myriapods: Complete 3D morphology of type specimens transcends conventional species description (Myriapoda, Chilopoda).

We present high-resolution X-ray microtomography (microCT) to enhance the standard morphological description of a recently described centipede, Eupolybothrus liburnicus Akkari, Komericki, Weigand, Edgecombe and Stoev, 2017. The 3D images of the holotype and paratype specimens are considered here as cybertypes for the species-a universal and virtual representation of the type material. This 'avatar' of the holotype is the first published male centipede cybertype. The microtomographic data of both types revealed further characters of systematic value and allowed us to hypothesise on the function of some of the male secondary structures and the mating behaviour of the species. Additionally, we compared part of the female reproductive system of E. liburnicus to species from the same genus, including E. cavernicolus Stoev & Komericki 2013, its closest congener. The high-resolution 3D image data have been uploaded to an open repository (MorphoSource.org) to serve in any subsequent study on the species and genus, as we believe this would catalyse biosystematic research on this and other arthropod groups.

A new cave centipede from Croatia, Eupolybothrus liburnicus sp. n., with notes on the subgenus Schizopolybothrus Verhoeff, 1934 (Chilopoda, Lithobiomorpha, Lithobiidae).

A new species of Eupolybothrus Verhoeff, 1907 discovered in caves of Velebit Mountain in Croatia is described. E. liburnicussp. n. exhibits a few morphological differences from its most similar congeners, all of which are attributed to the subgenus Schizopolybothrus Verhoeff, 1934, and two approaches to species delimitation using the COI barcode region identify it as distinct from the closely allied E. cavernicolus Stoev & Komericki, 2013. E. spiniger (Latzel, 1888) is redescribed and a lectotype is designated for it as well as E. caesar (Verhoeff, 1899) to stabilize their respective taxonomic status. The subspecies E. acherontis wardaranus Verhoeff, 1937, previously suspected to be a synonym of E. caesar (Verhoeff, 1899), is redescribed and its taxonomy revised after the study of type material whereas the identity of E. acherontis (Verhoeff, 1900) described from a female from southwest Trebinje (Bosnia and Herzegovina) remains unknown. Type material of E. stygis (Folkmanova, 1940) is confirmed to be lost and future designation of neotypes from topotypic specimens is necessary to stabilize its taxonomy. The importance of setal arrangement on the intermediate and 14th tergites and the sexual modifications on the male 15th prefemur for species identification is discussed in the light of present findings, and a review of the species of E. (Schizopolybothrus) that display these traits is also provided.

At the end of the rope: Geophilushadesi sp. n. - the world's deepest cave-dwelling centipede (Chilopoda, Geophilomorpha, Geophilidae).

A new geophilomorph centipede, Geophilushadesi sp. n., is described from caves in the Velebit Mountain, central Croatia. Together with Geophiluspersephones Foddai & Minelli, 1999, described from Pierre Saint-Martin cave in France, they are the only two remarkably troglomorphic geophilomorphs hitherto known. The new species apparently belongs to a group of Geophilus species inhabiting mainly Western and Southern Europe, with a uniquely modified pretarsus in the second maxillae. Geophilushadesi sp. n. shows unusual traits, some of which commonly found in troglobitic arthropods, including exceptionally elongated antennae, trunk segments and leg claws. The species is described upon specimens found in two caves at a depth below -250 m. Another two specimens apparently belonging to the same species have been recorded in another deep vertical cave at -980 m and -1100 m. The latter represents the world's deepest record of Chilopoda as a whole.

Eupolybothrus cavernicolus Komericki & Stoev sp. n. (Chilopoda: Lithobiomorpha: Lithobiidae): the first eukaryotic species description combining transcriptomic, DNA barcoding and micro-CT imaging data.

We demonstrate how a classical taxonomic description of a new species can be enhanced by applying new generation molecular methods, and novel computing and imaging technologies. A cave-dwelling centipede, Eupolybothrus cavernicolus Komericki & Stoev sp. n. (Chilopoda: Lithobiomorpha: Lithobiidae), found in a remote karst region in Knin, Croatia, is the first eukaryotic species for which, in addition to the traditional morphological description, we provide a fully sequenced transcriptome, a DNA barcode, detailed anatomical X-ray microtomography (micro-CT) scans, and a movie of the living specimen to document important traits of its ex-situ behaviour. By employing micro-CT scanning in a new species for the first time, we create a high-resolution morphological and anatomical dataset that allows virtual reconstructions of the specimen and subsequent interactive manipulation to test the recently introduced 'cybertype' notion. In addition, the transcriptome was recorded with a total of 67,785 scaffolds, having an average length of 812 bp and N50 of 1,448 bp (see GigaDB). Subsequent annotation of 22,866 scaffolds was conducted by tracing homologs against current available databases, including Nr, SwissProt and COG. This pilot project illustrates a workflow of producing, storing, publishing and disseminating large data sets associated with a description of a new taxon. All data have been deposited in publicly accessible repositories, such as GigaScience GigaDB, NCBI, BOLD, Morphbank and Morphosource, and the respective open licenses used ensure their accessibility and re-usability.