Chrysallida bjoernssoni, (Waren, 1991)

Høisaeter, Tore, 2014, The Pyramidellidae (Gastropoda, Heterobranchia) of Norway and adjacent waters. A taxonomic review, Fauna norvegica 34, pp. 7-78 : 21-22

‘Chrysallida’ bjoernssoni ( Warén, 1991)

Figure 21

Chrysallida bjoernssoni sp.n. - Warén, 1991:100 Chrysallida bjoernssoni Warén - Høisaeter 2009 Chrysallida (Trabecula) kronenbergi - van Aartsen et al.,

2000:41

Type material: Holotype (1.52 mm) and nine paratypes, SMNH 4092 and 4093.

Type locality: Southeastern Iceland, Skeidarardypet, c. 200 m.

Material seen: Norway – Norwegian Trench (61°30’N, 02°00’E, 311 m), 1 sh ; Troms, 17 shs.

Diagnosis: Shell: The most diagnostic character is the keeled, funnelshaped protoconch ( Figure 21 right), and Figure 33E in Warén (1991). Soft parts: Not known. Operculum: Not known.

Biology: Unknown.

Distribution: From Norway, only the material listed above is known. Three samples from the Andfjorden area, eight and two fairly well preserved shells from two Lophelia reef samples, and seven from a sample from Bleiksdjupet northwest of Andøya, (69°25’N, 200-700 m, stones and clay). In addition a single shell from the western ‘slope’ of the Norwegian Trench (83.11.17.5, 61°30’N, 02°00’E, 311 m). All of the Norwegian samples are from depths around or a little below 300 m. Only empty shells found, and thus not verified that it is still living here. Outside Norway, 20 shells on which the description was based from 200 m in south-eastern Iceland. The only known additional material is two shells from 156 m in eastern Greenland ( Warén 1991). With the material from Norwegian waters listed above, the distribution limit is moved considerably eastwards. See also Remarks below.

Remarks: In Warén (1991) the species is explicitely named for the Icelandic collector Johannes Björnsson, and spelled C. bjoernssoni . However the name of the collector is misspelled “Johannes Björnson” in the same sentence, the species name is spelled “ bjoernsoni ” in a figure caption. Chrysallida (Trabecula) kronenbergi van Aartsen et al., 2000 from deep water near the Azores, in many ways resemble C. bjoernssoni , but (according to van Aartsen et al.) lacks the distinct spirals that the latter species have. The SEM photograph accompanying their description clearly shows three spiral cords not crossing the axial ribs, and is almost indistinguishable from the SEM photo of C. bjoernssoni in Warén (1991) and the specimen at right in Figure 21 above. Van Aartsen et al. (2000) place their new species in the subgenus Trabecula , based on Chrysallida jeffreysiana ( Monterosato, 1884) . I do not agree as, judging from their SEM-photo, C. kronenbergi and C. jeffreysiana are very different morphologically. If C. kronenbergi is conspecific with C. bjoernssoni , then the species has a very wide distribution, from eastern Greenland, via Iceland and northern Norway, the Norwegian Trench to the bathyal (c. 600 m) near the Azores.

Figures

Figure 21. Chrysallida bjoernssoni, Bleiksdjupet, NW of Andenes, 69°25’N, 15°47’E, 700-200 m, 1.7 mm (ZMBN 82384) (left) and Norwegian Trench, 62°30’N, 02°00’E, 311m, 1.25 mm (ZMBN 82385). Figure 22. Chrysallida brattstroemi. Outer Korsfjorden 60°07.5’N, 4°51’E, 317-315 m, 1.25 and 1.1 mm (ZMBN 82285). Figure 23. Chrysallida eximia, Fugløyfjorden, 67°01’N, 13°50.5’E, 70-50 m, 1.70 mm (ZMBN 82491) (left), and Raunefjorden, Liholmsrennen, 60°18’N, 5°10’ E, 70-55 m, 1.35 mm (ZMBN 82455. Pigmented mantle organ at bottom centre (not to scale). Figure 24. Chrysallida hoeisaeteri. Two specimens from Andfjorden, Ørja, 69°13.9’N, 16°40.9’E, 2.00 and 1.25 mm respectively (ZMBN 82379). Figure 25. Chrysallida sublustris. Lower slope, 63°13’N, 03°07’E, 1003 m, 3.05 mm(82.08.23.1), and upper slope, 62°12’N, 00°00’E, 708 m, 2.30 mm (83.06.02.1). Figure 26. Chrysallida sublustris, protoconchs of two specimens from same localities as in Figure 23.