Arrenurus (Arrenurus) ornatus George, 1900

Type material: One male paratype, catalogue number 42261-1418-VIE/035 (GBIF 2022).

Type locality: United Kingdom (GBIF 2022) .

Geographical distribution: Western Palaearctic (Gerecke et al. 2016).

Distribution in Portugal: South: Alentejo, in Ribeira de Odivelas (Lundblad 1956).

Ecological notes: Freshwater, in slow-moving streams, ponds and lakes; Larval insects hosts: Zygoptera odonates (Gerecke et al. 2016); present in plants, such as Batrachium spp., Myriophyllum spp., Nymphea spp. (Lundblad 1956) .

Arrenurus (Arrenurus) securifer Viets, 1930

Type material: Paratypes: One male and one deposited in SMF, catalogue numbers 42372-3916-VIE/040 and one male and one female 42373-3917-VIE/040 (AQUILA 2022) .

Type locality: Spain: Madrid (Valdecasas 1988), in Manzanares River, Charca de Marmoto (Viets 1930).

Geographical distribution: Southern France and Iberian Peninsula (Gerecke et al. 2016).

Distribution in Portugal: Centre: Beira Alta, in Côa River, near 10 km to Vilar Formoso; South: Alentejo, in Ribeira de Odivelas (Lundblad 1956).

Ecological notes: Freshwater, in streams, ponds and lakes (Gerecke et al. 2016), as well as on sandy bottoms (Viets 1930); present in plants, such as Batrachium spp., Juncus spp., Myriophyllum spp., Nymphea spp. (Lundblad 1956) .

Arrenurus (Arrenurus) szalayi Lundblad, 1954

Type material: Deposited in NRM: Holotype one male Lundblad No. Präp. 4403 (Lundblad 1954); one female Lundblad No. Präp. 4405 (Lundblad 1956).

Type locality: Portugal: Alentejo, in Ribeira de Odivelas (Lundblad 1954, 1956).

Geographical distribution: Iberian Peninsula (Camacho & Valdecasas 1988; Lundblad 1956; Valdecasas 1988).

Distribution in Portugal: South: Alentejo, in Ribeira de Odivelas (Lundblad 1954, 1956).

Ecological notes: Freshwater, in permanent ponds with grasses and algae (Camacho & Valdecasas 1988).

Arrenurus (Megaluracarus) globator (Müller, 1776)

Synonym: Hydrachna globator Müller, 1776 (original designation)

Type material: Unknown, possibly lost.

Type locality: Denmark (probably surroundings of Copenhagen) or Norway (Müller 1776) .

Geographical distribution: Palaearctic: Europe, Türkiye, Iran, Altai, Japan (Gerecke et al. 2016).

Distribution in Portugal: South: Alentejo, in Ribeira de Odivelas (Lundblad 1956).

Ecological notes: Freshwater, with a preference for slow-moving streams, lakes and ponds; partially eutrophicationtolerant species; Larval insects hosts: Culicidae (Diptera), Chironomidae (Diptera), Dytiscidae (Coleoptera), Gyrinidae (Coleoptera) (Gerecke et al. 2016); present in plants, such as Batrachium spp., Myriophyllum spp., Nymphea spp. (Lundblad 1956) .