The number of undiscovered species in Norway is estimated to be 16131. This means that only 73 % of the biodiversity in Norway is known. The largest proportion of unknown species are in the species groups sawflies, wasps, ants and bees (Hymenoptera), true flies (Diptera) and the fungi (Ascomycota).

The total number of species in Norway is estimated at nearly 60 000 species (59 836 species). This means that around 16 000 species in Norway are still undiscovered. The number is an estimated minimum since some species groups lack an assessment of the number of species in Norway. This applies first and foremost to many poorly surveyed groups of microalgae, where the knowledge is too poor for estimates to be made with a reasonable degree of certainty.

Nine species groups make up nearly 75 % of the undiscovered species in Norway and the largest groups are sawflies, wasps, ants and bees (Hymenoptera), true flies (Diptera) and the fungi phylum (Ascomycota).

 

The number of undiscovered species in Norway divided by species groups: sawflies, wasps, ants and bees (Hymenoptera); fungi phylum (Ascomycota); true flies (Diptera); aster family (Asteraceae); mites (Acari); the fungi (Agaricomycotina); segmented worms (Annelida), amoebae (Rhizopoda) and lice (Phthiraptera). The statistics do not include the majority of microalgae.

High number of undescribed species among Hymenoptera and Diptera

Among the Hymenoptera there are five large superfamiles of wasps, mainly parasitoid species, that contribute to the number of unknown species: Cerapronoidea, Chacidoidea, Cynipoidea, Ichneumonoidea and Proctotrupoidea. These five groups are thought to contain well over 2600 unknown species. Despite many new wasp species being discovered in recent years, wasps still retain their status as perhaps the most poorly surveyed larger species group in Norway.

In the order Diptera, three large families represent more than half of the estimate of unknown species: dark-winged fungus gnats (Sciaridae) with 423 unknown species, gall midges (Cecidomyiidae) with 408 unknown species and phorid flies (Phoridae) with 226 unknown species.

An unknown number of mites and lice

Among arthropods, mites (Acari) are another large and poorly studied group. It is thought that nearly half of the species diversity is still to be discovered. In 2015, the number of known mite species in Norway was 1062 but there are probably around 2000 species of mites in Norway.

Lice (Phthiraptera) are the most poorly studied order of insects. We assume that only 7 % of the genuine biodiversity is known. The uncertainty is associated with two suborders of chewing lice (Amblycera and Ischnocera). These two groups contain only 26 described species but the total number is thought to be around 500 species. The sucking lice (Anoplura) are considered to be relatively well known (20 of the 25 estimated species are known).

 

The estimated proportion of undiscovered species in Norway among the species groups true flies (Diptera), sawflies, wasps, ants and bees (Hymenoptera) and mites (Acari).

More than 40 % of segmented worms (Annelida) species are still undiscovered

There are 811 described species of segmented worms (Annelida) in Norway but we estimate that we have slightly more than 1400 species. This implies that approximately only 57 % of the biodiversity is known. The proportion of undiscovered species is assumed to be especially high in the orders Enchytraeida (300 known species) and tubificina (105 unknown species). Much new knowledge has come to light and will continue to do so through the survey of annelids that is underway in the Norwegian Taxonomy Initiative (Artsprosjektet). Both Polychaeta and Oligochaeta, such as earthworms and pot worms (Enchytraeidae) are being surveyed.

A third of Ascomycota are still undiscovered

There are a particularly high number of unknown species in the fungi group Ascomycota and as many as 2433 species (35 %) are still considered to be undiscovered in Norway. The proportion of unknown species are relatively similar for the assessed subgroups but Dothideomycetes and Leotiomycetes are particulary poorly studied. The proportion of unknown species in these two groups are estimated to be 56 % and 53 % respectively of the total biodiversity.

In the subphylum Agaricomycotina, which belongs to the Basidiomycota, there are two families that are distinguished by a high proportion of unknown species: Cortinariaceae, due to many undiscovered species in the genus Cortinarius, and family Thelephoraceae. Surveys carried out as part of the Norwegian Taxonomy Initiative have revealed that many cryptic species hide in these groups.

Asteraceae, Ranunculaceae and Roseaceae give taxonomists a headache

There are also many undiscovered species in Norway in the plant kingdom (Plantae). Flowering plants (angiosperms) are generally well known, but there are three groups that contribute to a relatively high estimate of undiscovered species: Asteraceae (1439 species), Ranunculaceae (11 species) and Rosaceae (59 species). This is due to the high number of cryptic species in Ranunculaceae and in the Rosa, Rubus, Alchemilla, Crataegus and Sorbus genera in Rosaceae.

In Norway there are 296 described species of liverworts but we estimate that there are somewhat more than 330 species in Nroway. The majority of the species are small and difficult to discover, and they are also often difficulty to identify (at species level). There is also a high diversity of undiscovered species in the groups green algae (Chlorophya) and Streptophyta but in this case the knowledge foundation is too poor to be able to estimate the number of undiscovered species.

Estimated number of undiscovered species in Norway in the Asteraceae, Ranunculaceae and Rosaceae families.

Biodiversity in the Alveolata and Amoebozoa kingdoms is poorly known

In general terms the biodiversity in Alveolata and Amoebozoa is poorly known. In Amoebozoa we have, for example, a poor overview of the diversity of amoeba (Rhizopoda). Only four species are known from Norway but the genuine number of species is estimated to be around 500. For the other species groups in Amoebozoa the number of species is also estimated to be very high.