Even though Congeria has long been thought to be a single pan-Dinaric species (Congeria kusceri Bole, 1962), phylogenetic analyses have recently clarified that it consists of three distinct species, namely Congeria kusceri Bole, 1962, Congeria mulaomerovici Morton and Bilandžija, 2013, and Congeria jalzici Morton and Bilandžija, 2013 (Bilandžija et al. 2013).

This taxon was regarded by MolluscaBase (April 2023) as interim unpublished as it failed to fulfil ICZN Article 8 regarding publishing species description in an electronically issued article (M. Lopes-Lima pers. comm. 2021), but the species was formally described by Morton and Bilandžija (2023).

The genus Congeria is endemic to Europe and known from only 51 sites in the Dinaric karst (Bilandžija et al. 2022).

Global and European regional assessment: Vulnerable (VU)
EU 27 regional assessment: Not Recorded

The European endemic species Congeria mulaomerovici is assessed as Vulnerable under criterion D2 as it inhabits a very restricted area and has a very limited resilience and recovery potential, and potential threats to the species' habitat could have rapid and severe impacts on the species, potentially causing it to rapidly become Critically Endangered or Extinct in the future. The species occurs only at one location and the estimated extent of occurrence (EOO) is between 8-123 km², with the area of occupancy (AOO) being estimated between 8-20 km².

There is no information about the decline of the quality of habitat, however further research is needed as the biology of the species and its threats are poorly known. Any changes in the groundwater quality or changes in hydrological properties could have a devastating impact on this species.

This species is known from live subpopulations in three sites in northwestern Bosnia and Herzegovina (caves Suvaja, Dabarska pećina and Oko), and from an additional three sites in the same region where empty shells were found (Bilandžija et al. 2013, Bilandžija et al. 2022, SubBioDB 2022). These caves can be considered as a single location, as they belong to the same subterranean hydrosystem.

At spring in Oko izvor and cave Suvaja pećina the species is found in large numbers, whereas in Dabarska pećina only a few specimens have been found.

Congeria mulaomerovici inhabits subterranean aquatic habitats that are almost constantly underwater, where it lives attached to the stone surface. Animals feed by filtering small organic matter from the water.

The information on the more studied related species, C. kusceri and C. jalzici, shows that the animals can be found in larger groups and can survive some time out of the water (in times of low water flows). Probably in that time, high air humidity is important (Bilandžija et al. 2014). The reproductive strategy and estimated life span are known for closely related Congeria kusceri. The sperm is released into the water, and then in all probability ‘inhaled’ by the females from the water. Embryogenesis and early development occur within the mother, then larvae or young adults are released through the birth canal (Morton and Puljas 2013) and live up to 50 years (Puljas et al. 2014). The biotic interactions are poorly known.

This species is especially susceptible to threats due to its narrow distribution. One of the identified potential threats is the pollution of groundwater due to illegal dumps, unsolved wastewater management or agricultural effluents. Furthermore, any changes to natural hydrological regimes such as canalisation of watercourses or building accumulations would be problematic. Currently, we have no information that any threats are impacting this species at present, so further research is needed to understand the state of the population and threats.

This species is neither used nor subject to trade.

The species C. mulaomerovici is indirectly subjected to some conservation measures and legislations under the nominal taxon of C. kusceri as it is the species that it derives from. It is listed on Revised Annex I of Resolution 6 (1998) of the Bern Convention and was previously included in IUCN Red List evaluations (Bilandžija 2011). Furthermore, even though Bosnia and Herzegovina is not a Member of the European Union, candidate Natura 2000 site Lušci-Palanačko polje was proposed, based on the qualification species Congeria kusceri, listed on Annexes II and IV of Habitat directive (EU Directive 92/43/EEC). It is important to note that this is only a proposed Natura 2000 site, without any formal implication. The subterranean habitats and fauna are also protected by entity-level legislation in Bosnia and Herzegovina (Official Gazette of FBIH, No. 66/13).

The legal protection status of the C. mulaomerovici in Bosnia and Herzegovina needs to be established as the species is distributed in an extremely small area and therefore any threats could affect all populations. Actions to prevent pollution and hydrological changes would ensure the good condition of the populations in the future and include establishing and implementing adequate conservation policies and raising awareness through education. Assessment of the current conservation status of the populations is needed, together with the development and implementation of monitoring.

Additional research on the biology, ecology, and genetics of the species is needed. Those actions require the allocation of adequate funds and intervention by national authorities. This is the least studied species from the genus Congeria, and we infer many of the species characteristics from related species. Therefore, knowledge of the basic biological and ecological characteristics of the species is needed, including studies in the species’ natural environment. It is important to enhance genetic studies, to work towards understanding the resilience potential of the species, to evaluate the current status of survival populations, and develop a monitoring scheme.