Pseudostygarctus mirabilis Grimaldi

Kaczmarek, Łukasz, Bartels, Paul J., Roszkowska, Milena & Nelson, Diane R., 2015, The Zoogeography of Marine Tardigrada, Zootaxa 4037 (1), pp. 1-189 : 141

166. Pseudostygarctus mirabilis Grimaldi de Zio, D’Addabbo Gallo & Morone De Lucia, 1998

Pseudostygarctus mirabilis sp. nov. (Grimaldi de Zio et al. 1998)

Pseudostygarctus mirabilis ( Sandulli et al. 1999)

Pseudostygarctus mirabilis Grimaldi de Zio et al., 1998 (D’Addabbo Gallo et al. 2001, Grimaldi de Zio & D’Addabbo Gallo 2001)

Terra typica: Tyrrhenian Sea ( Italy, Europe)

Adriatic Sea:

• 42°06 ′ N, 15°29′E; 10 m bsl: [FAO37] Italy, Foggia Province, Tremiti Islands, southern area of San Domino Island, in the proximity of Punta Zio Cesare, submarine cave Grotta delle Viole, external cave’s entrance, coarse organogenic detritus. D’Addabbo Gallo et al. (2001), Grimaldi de Zio & D’Addabbo Gallo (2001), Grimaldi de Zio et al. (2003)

• 42°06 ′ N, 15°29′E; 7 m bsl: [FAO37] Italy, Foggia Province, Tremiti Islands, southern area of San Domino Island, in the proximity of Punta Zio Cesare, submarine cave Grotta delle Viole, ca. 20 m from the cave’s entrance, coarse organogenic detritus. D’Addabbo Gallo et al. (2001), Grimaldi de Zio & D’Addabbo Gallo (2001), Grimaldi de Zio et al. (2003)

• 42°06′N, 15°29′E; 5–10 m bsl: [FAO37] Italy, Foggia Province, Tremiti Islands, San Domino Island, Punta Zio Cesare, cave Grotta delle Viole, 0–10 cm depth, 80% coarse organogenic sand, 3% silt and clay, (mean diameter = 0.125 mm). Sandulli et al. (1999), Grimaldi de Zio & D’Addabbo Gallo (2001), Grimaldi de Zio et al. (2003)

Tyrrhenian Sea:

• 38°36 ′ 0 0 ′′ N, 14°55′00′′E; 40 m bsl: [FAO37] Type Locality: Italy, Sicily Region, Aeolian Islands, Secca del Capo coralligenous bank, subtidal zone, coarse coralligenous detritus. Grimaldi et al. (1998)

Record numbers (Sea/Ocean classification): Adriatic Sea: 3, Tyrrhenian Sea: 1; total: 4.

Record numbers (FAO classification): FAO37: 4; total: 4.

Remarks: Like P. rugosus (see below), this species is known only from a few very specific localities in the Mediterranean region (mostly marine caves), which may suggest that this species is troglobiotic. However, it has also been reported from the open sea at 40 m bsl. It is possible that P. mirabilis and P. rugosus are deep sea elements which have found refugia in marine caves. A hypothesis was proposed for other marine invertebrates (mostly crustaceans) by Hart et al. (1985) of links between marine cave and deep water species in the form of crevices along which animals could travel and that caves could persist over time to contain old fauna elements and act as refugia. Villora-Moreno (1996) noted that marine cave environments could be similar to deep sea habitats and provide refugia for deep-sea tardigrades and he adopted this hypothesis to explain the discovery of a new genus, Trogloarctus , in a marine cave ( Trogloarctus is a member of the deep sea family Coronarctidae and shows many similarities to other deep sea species). These discussions could explain the rarity and distribution of P. mirabilis and P. rugosus .