Hemithiris psittacea ( Gmelin, 1791 )

Hansen, Jesper, 2024, Brachiopods of the Norwegian fauna northern North Atlantic and Arctic, with a focus on, Fauna norvegica 43, pp. 12-68 : 25-27

Hemithiris psittacea ( Gmelin, 1791)

Figures 1A, 1B, 1F, 1J , 9 , 10

Anomia rostrum psittaci Chemnitz, 1785, p. 106 , pl. 78, figs. 713a–b. Anomia psittacea Gmelin, 1791, p. 3348 .

Lampas psittacea – Calonne & Humphreys (1797), p. 45. Terebratula psittacea – Lamarck (1819), p. 248.

Gypidia psittacea – Menke (1830), p. 96.

Hypothyris psittacea – King (1846), p. 28.

Hemithiris psittacea – d’Orbigny (1847b), p. 246.

Rhynchonella psittacea – Davidson (1852a), p. 251 –253, pl. xiii, figs. 1a–b.

Rhynchonella (Hemithyris) psittacea – Dall (1873), p. 196.

Description: Shell with subtriangular or subpentagonal outline and rather acutely pointed beak. Large specimens approximately as wide as long. Anterior commissure uniplicate on specimens larger than 16 mm, while gently unisulcate on specimens smaller than 4 mm. Lateral valve commissure unevenly curved. Ornament developing from 1.2–4 mm valve length and outwards as fine, broad and very flat radiating ribs or relatively well-separated striae. Shell matrix impunctate. Colour dark bluish, dark grey or brownish except in small specimens, which are light-coloured and transparent. Ventral umbo beak-shaped and rather long. Rudimentary triangular deltidial plates not joining but forming a roughly U-shaped pedicle opening. Distinct pedicle collar. Elongate, unbranched pedicel. Small specimens with setae protruding as prolongation of striae. Well-developed dental plates. Crura flattened. Weak and short dorsal median ridge. Maximum length 30.4 mm.

Depth range: 0–2078 m depth, though rarely found deeper than 400 m, and only two reports from deeper than 1000 m depth (Cooper Superfamily Norelloidea Ager, 1959 1973a; this study). Family FRIELEIIDAE Cooper, 1959

Temperature range: -2–12˚C ( Knipowitsch 1901; Ullmann et Genus Hispanirhynchia Thomson, 1927 al. 2017).

Salinity range: 26.2–35.5 ( Zezina 2008; this study).

Oxygen range: Oxygen saturation 83–105% (this study). Hispanirhynchia cornea (Fischer, in Davidson 1887)

Current velocity: Mean current velocity of 2.6–11.7 cm /s, with Figures 11 , 12 daily maxima of 4–30 cm /s and an absolute maximum velocity of 13.3–72.2 cm /s over 1 month of measurement (this study). Rhynchonella cornea Fischer , in Davidson (1887), p. 171–172, pl. 25,

Substrate: Usually attached to small pebbles, shells or rocks, figs. 2–4. but can be attached to any kind of hard surface such as serpulid and Rhynchonella (Hemithyris) cornea – Fischer & OEhlert (1891), p. Nothria tubes, bryozoans, Cirripedia fragments, rhodoliths or even 13–18, pl. 1, figs. 2a–u. Foraminifera and sand grains (this study). Found on mud- or sand- Hemithyris cornea – Dall (1920), p. 288–289. dominated sea floors mixed with shell sand, or on gravel, pebbles, Hispanirhynchia cornea – Thomson (1927), p. 159–161, fig. 49. stones, calcareous red algae, rock grounds or vertical cliffs (Leche 1878; Posselt 1898; Arndt & Grieg 1933; Wesenberg-Lund 1940a,b; Description: Shell low equibiconvex to inflated, but with flattened Thomsen 2012; this study). top in anterior profile. Outline elongate subtriangular. Ventral umbo

Geography: Arctic Ocean, E and W Canada, E and W Greenland, rather short and incurved beak-shaped. Rectimarginate to faintly Svalbard, Jan Mayen, Kara Sea, Laptev Sea, the White Sea, Norway unisulcate anterior and straight lateral commissure. Triangular, (from Folda in Nordland and north), S and W of Iceland, W USA, and disjunct deltidial plates more than halfway enclosing small to Japan (e.g., Posselt 1898; Lamy 1913; Grieg 1933; Brunton & Curry medium-sized pedicle opening. Short pedicle collar. Ornamentation of 1979; Zezina 1997b, 2008; this study). very fine, dense and radiating striation as well as concentric growth

The species is also reported from the North Sea, Faroe Islands, at lines. Shell matrix impunctate. Colour light yellow to brownish. the Hebrides, Ireland, Orkney Isles and Shetland Isles (e.g., Lyell 1842; Teeth supported by dental plates. Subhorizontal inner hinge plates in Dall 1920; Brunton & Curry 1979; Thomsen 2001). Following Jeffreys dorsal valve connecting socket ridges with crural bases. Lophophore (1863, 1878) and based on specimens examined at the Natural History supported by short, thin crura. Sharp-edged short dorsal median Museum of London, all certain observations around the British Isles septum. Maximum length 36 mm. are empty and likely of glacial age. The reported presence at the Faroe Depth range: 439–3645 m depth ( Cooper 1981a; Zezina 2010). Islands by Lyell (1842) was based on the apparent glacial material Davidson (1887) gave the extremely shallow depth of 105 m off (BMNH PI ZB 1667). Additionally, according to Thomsen (2001), Southern Portugal for the syntype specimen sampled during the there are no other possible recent specimens known from the area. Talisman Expedition in 1883. However, as concluded by Emig (2016)

Jeffreys (1878) mentioned the species from Drontheim this location is wrong and should have been the Talisman station off (=Trondheim) in Trøndelag, Norway, while Wesenberg-Lund (1939) Morocco at 1050 m depth reported by Fischer & OEhlert (1891). reported it from Brettingsnes in the Trondheimsfjord. However, the Temperature range: 6–12˚C ( Brand et al. 2003). latter are two empty shells most likely of glacial age. The first was Salinity range: 35–36 ( Brand et al. 2003). a re-occurring mistake that Jeffreys (1869b: 164) admitted, using Geography: English Channel, off SW Ireland, south to the Trondheim instead of Tromsø. Azores, the Canary Islands and Sudan ( Fischer & OEhlert 1891;

Dall (1920) listed a specimen from Bergen in Vestland, Norway. Brunton & Curry 1979; Cooper 1981a; Logan et al. 2007; Zezina According to the collection list, the University Museum of Bergen also 2014). houses a specimen from that area. However, the latter was missing, Remarks: Although the year of description is often given as 1886 and both are most likely not recent shells. since that is written on the first page of the paper, it was published

In the collections housed at the Natural History Museum of in 1887. London was a single specimen collected alive ( BMNH PI B 24769 ) No holotype was elected in the original description, but Emig with no other information than ‘ North Sea’ . The label dates it to before (2016) has subsequently elected the Talisman station off Morocco the year 1900. However , it seems more likely that the information is at 1050 m depth as the type locality. Most type specimens from the incorrect rather than the specimen actually is originating from the Talisman expedition have lost their labelling according to Alvarez North Sea. (2016), but based on the provided pictures it seems most likely that

Remarks: The species was first named, described and beautifully the bigger of the two specimens labelled ML-ZOO-MAL-00133 illustrated by Chemnitz (1785). However, since he used a trinomial is identical with pl. 25, figure 2–2c of Davidson (1887) from the name instead of the Linnean binominal system, Gmelin (1791) is Talisman expedition. That would then be a candidate for election as accepted as having named the species. a lectotype.

Within Norwegian waters, it seems that this Arctic and subarctic species has been retreating northward within the last century since no live specimens appear to have been collected south of 69.2°N in Nordland and Troms after 1923, while it was collected from several localities south to 67.6°N before then .

Despite its wide depth range, Hemithiris psittacea is primarily associated with coastal environments.

Figures

Figure 1. Terminology used in the paper. d–g show different shapes of the anterior commissure. Species shown: Hemithiris psittacea (a, b, f, j); juvenile Terebratulina septentrionalis (c); Glaciarcula spitzbergensis (d, h); Dallina septigera (e, g); Macandrevia cranium (i).

Figure 9. Hemithiris psittacea. a–c: dorsal, lateral and anterior views of specimen, Hinlopen Strait, Svalbard, 337 m (JH); d: dorsal view of specimen, Hinlopen Strait, Svalbard, 337 m (JH); e–f: inner sides of dorsal and ventral valves, Heleysund, Svalbard, 68 m (JH); g–h: inner sides of dorsal and ventral valves of an empty shell, Hinlopen Strait, Svalbard, 337 m (JH);i–m: dorsal, ventral, lateral, anterior and posterior views of juvenile specimen, TSZ 3012 (APN), Jernøya in Finnmark, Norway, 73 m. Scalebar 1mm. Photos: Jesper Hansen.

Figure 10. Distribution of Hemithiris psittacea. Colours mark which century the specimens were collected in. Possible fossil empty shells in need of verification are marked as such.

Figure 11. Hispanirhynchia cornea. a–f: dorsal, ventral, dorsal inner, ventral inner, lateral and anterior views of syntype BMNH PI ZB 281, English Channel, 1262 m; g–i: outer side, detail of ornamentation and inner side of the ventral valve of syntype BMNH PI ZB 4954, English Channel, 1262 m. Solid scalebar 1mm and segmented calebar 5mm. Photos: Jesper Hansen.

Figure 12. Distribution of Hispanirhynchia cornea.