Lohmannella falcata ( Hodge, 1863 )

Abé, Hiroshi, 2021, Taxonomic review of the subfamily Lohmannellinae (Acari: Trombidiformes Halacaridae) with morphological comparisons among genera, Zootaxa 4980 (2), pp. 201-255 : 212-213

Lohmannella falcata ( Hodge, 1863)

Diagnosis. Two corneae usually present (varies 0–2). Ds-2 on membranous cuticle. Ds-3 on membranous cuticle. Two dorsal setae on PE. Female with 32–34 Pgs and 8 Sgs. Male with 75–79 Pgs and 8 Sgs. Tr I–IV with 1-1- 1-1 setae; Bf I–IV with 3-3-3-3 setae; Tf I–IV with 6-7-5-5 setae; Gn I–IV with 8-8-5-5 setae, (2–4)-4-2-2 Bp setae; Tb I–IV with 11-9-7-6 setae, (5,6)-5-4-3 Bp setae; Ta I–IV with 3-3-4-(3,4) dorsal setae, (1,2)-1-2-1 Bp setae. Lc I with either no or unidentate accessory process. Idiosoma length 298–515 in female, 335–490 in male, 298–402 in DN, 240–292 in PN, 168 in LV. Idiosoma width 291 ( idiosoma length 374) and 308 ( idiosoma length 375) in male. Gnathosoma length 232–260 ( idiosoma length 397–417) in female, 218 ( idiosoma length 375) in male. Ratio of gnathosoma to idiosoma 0.56–0.65. Ratio of P-2 to P-1 3.70–4.40.

Remarks. The species was originally described by Hodge (1863) under the name of Leptognathus falcatus . Trouessartella falcata Lohmann, 1901 and Leptognathus marinus Lohmann, 1889 are equivalent to this species. This species has very long rostrum and palpi. In the male, the genital foramen is surrounded by a dense corona of more than 60 Pgs and flanked by 4 or 5 pairs of outlying setae. Female, male, DN, PN, and LV are known.

L. falcata beringi was described by Newell (1951b) as a subspecies of L. falcata on the basis of female specimens collected from calcareous algae at intertidal zone and sands and gravels at a depth of 39.6 m at Attu Is., St. Paul Is., Umnak, Adak, Aleutian Passes, and Wainwright in USA ( Newell 1951a, b; Bartsch 1977b). This species is different from L. falcata in having heavier palpi and Lc I–IV with delicate accessory teeth. Bartsch (2003b) suggested that this subspecies could be raised to a species rank, L. beringi , including specimens recorded as L. falcata from Gulf of Anadyr and the Kuril Is. by Makarova (1976, 1977, 1978). However, the discrimination is based only on quantitative characters. Further consideration based on the qualitative and/or genetic characteristics will be desirable. This subspecies was deposited in USNMNHW.

This species has wide habitat range from intertidal to abyssal zones. This species inhabits constatly submerged areas. Bartsch (2020) mentioned that the specimens identified to L. falcata from 2500–3000 m depth would be distinct from L. falcata and those from 400-500 m depth at Golfe de Gascogne ( Trouessart & Neumann 1896) were also dubious. Newell (1984) suggested that specimens named as L. falcata collected in the southern hemisphere would not to be conspecific with L. falcata . Bartsch (2009a) mentioned that the records from Kerguelen and Antarctic Peninsula by Lohmann (1907a, b) and Trouessart (1914) were certainly incorrect due to mis-identification. As noted by Newell (1951b), either L. falcata is highly variable, or there will be a complex of several cryptic species. Newell (1984) stated that records of L. falcata from many localities were based on similar but distinct species and the presumed cosmopolitan distibution of this species was open to question. Bartsch (2003b, 2009a) postulated that the distribution of L. falcata should be restricted to the intertidal to subtidal zones in the western and eastern North Atlantic, the North Sea, the Baltic Sea, the Mediterranean, and the Black Sea. Collecting record as the name of L. falcata covers very wide habitat and distributional ranges and it is difficult to certify actual ecological and geographical ranges of this species here. Therefore, for the time being, so far published records under the name of L. falcata are compiled below.

Habitat. Littoral–Bathyal zones (0–2992 m): Coarse sands, gravels, shell fragments, sediments with Lima hians, Lasaea rubra ( Bivalvia), algae ( Corallina officinalis , Corallina spp. , Porphyra umbilialis , Phyllophora spp. , Laurencia obtusa , Laurencia pinnatifida , Lithothamnion spp. (Rhodophyta) , Cystoseira crinita , Fucus serratus , Laminaria digitata , Laminaria ochroleuca, Alaria macroptera, Stictyosiphon tortillis, Chordaria flagelliformis (Phaeophyta) , Enteromorpha spp. , Ulva lactuca , Cladophora spp. (Chlorophyta)), Laminaria -hapteres, sponges, mussels ( Mytilus edulis , Mytilus spp. , Modiolus spp. ), barnacles ( Semibalanus balanoides ), bryozoans, hydroids, ascidians ( Ascidiella aspersa ), and lichens ( Lichina pygmaea ).

Distribution. North Atlantic Ocean: St. Andrews, New Brunswick, Rhode Island, Pettaquamscutt, Block Island [ USA]. Hatte Sund, Bergen [ Norway]. Skagerrak coast, Trosa (Askö Is.), Bonden Is., Hindersön (Gulf of Bothnia) [ Sweden]. Store Baelt, Langeland Baelt, Öresund [ Denmark]. Heiligenhafen, Kiel (Kieler Förde), Sylt, Helgoland, Scholpin-, Stolper-, Mittel- and Hoborg-Bank [ Germany]. Den Helder, Vlissingen [ Netherlands]. Pasvde-Calais, Wimereux, Grandcamp-les-Bains, St. Marcouf, Omonville-la-Rogue, Granville, Roscoff (Bay of Morlaix), Le Croisic (Bay of Biscay), Bay of Arcachon [ France]. Mouro Is. (43°28’24’’N, 3°45’22’’W) [ Spain]. West Cork, West Galway, Blacksod Bay, West Donegal [ Ireland]. St. Andrews, Northumberland, Cullercoats, Sunderland, Seaham, Whitby, Robin Hood’s Bay (Yorkshire coast), Norfolk, Whitstable, Herne bay, Duke Rock, Dorset, Devon, Plymouth, Cornwall, Scilly Isles, Gower Peninsula, Pembrokeshire, Dale, Bangor, Caernarvon, Menai Straits, Isle of Cumbrae, Down, Strangford Narrows, Hebrides, Shetlands [ UK]. Mediterranean: Banyuls-sur-Mer, Le Troc, Les Elmes, Peyrefitte, Île If, Île Ratonneau [ France]. Meloria [ Italy]. Hamitbey Plajý (Antalya) [ Turkey]. Split [Dalmatia ( Croatia)]. Monaco [ Monaco]. Black Sea: Sozopol, Burgas, Pomorie, Anchialo [ Bulgaria]. Vama Veche, Agigea, Danube Delta [ Romania]. Odessa Bay [ Ukraine]. Caucasian coast [ Russia]. North Pacific Ocean: Provideniya, Zaliv Kresta, Kamchatka, Kuril Is. (Paramushir, Simushir) [ Russia]. South Pacific Ocean: Tiera del Fuego [ Argentina]. Indian Ocean: Kerguelen Is. [ France]. Antarctic Ocean: George V Coast, Palmer Archipelago, Victoria Land, Port- Lockroy, Peterman Is., Gauss-Station, Wilhelm II Coast [ Antarctica].

References. André (1928, 1933, 1940, 1946), Andre & Lamy (1930), Angelier (1950, 1951, 1953a), Antipa (1941), Arndt & Viets (1939), Baçesco (1963), Baker (1982), Bamber (1982), Bartsch (1972, 1973a, b, 1975, 1976, 1977b, 1978a, 1979a, d, e, 1982b, 1983, 1985a, b, 1986b, 1988b, 1989a, b, c, 1991b, 2004b), Bartsch & Smit (2006), Brady (1875), Chartosia et al. (2018), Chichkoff (1907, 1912), Dahl (1948), Dalenius (1965), Delamare Deboutteville (1954), Farran (1915), Fountain (1949, 1953), Gadeau de Kerville (1894, 1898, 1901), Giard (1888), Gimbel (1919), Green & Macquitty (1987), Gressitt (1967), Hagerman (1966), Halbert (1915), Hallas (1978), Hamond (1973), Hodge (1863), Imamura (1968), Kautsky (1974), Konnerth-Ionescu (1971 a, b, 1981), Kramer (1879), Kussakin & Ivanova (1978), Kussakin et al. (1978), Lohmann (1889, 1893a, b, 1901, 1907a, b), Makarova (1976, 1977, 1978), Makkaveeva (1965), Marinov (1964), Morselli (1969), Motaş (1961), Motaş & Şoarec (1940), Motaş & Tanasachi (1962), Murray (1877), Newell (1947, 1951 b, 1967, 1984), Petrova (1979, 1984), Pugh (1988), Pugh & King (1985), Remane (1955), Riesgo et al. (2010), Schulz (1933, 1935), Sokolov (1952), Sokolov & Yankovskaya (1972), Somerfield (1988, 1991), Somerfield & Jeal (1996), Svenonius (1949), Thor (1931), Trouessart (1888a, b, 1889a, b, 1893, 1896b, 1914), Trouessart & Neumann (1894a, b, 1896, 1898, 1901, 1907), Valkanov (1957), Viets (1927a, c, 1928a, c, 1931, 1936, 1940, 1941, 1950a), Vorobyeva & Yaroshenko (1979).

Depository. HMN.