Mendicula, Iredale, 1924

Mendicula View in CoL “ ingolfi ” Ockelmann MS

Figs 10–12

In the archive, this species is represented by stipple drawings of the shell ( Fig. 10A), hinge ( Fig. 10B) and prodissoconch ( Fig. 10C) from Ingolf stn 36; 61°50′ N, 56°21′ W, at a depth of 2600 m, off SW Greenland in the Labrador Sea. It would appear that Ockelmann was never very sure about this species as the following specimens are present: 1 specimen in spirit from Ingolf stn 36 labelled “Ingolf Stn 36 1435 fathoms [= 2624m], type ” (NHMD-1175754); 4 specimens in spirit labelled “Ingolf Bundprove [bottom sample] stn 36” (NHMD-1175755) ( Fig. 11G View Fig ); 1 specimen labelled “ Thyasira n. sp. Ingolf Bundprove stn 25” (NHMD-1175761); 1 dry shell labelled “ T. ( Mendicula ) ‘ ingolfi ’ n. sp. L.G.O. stn 49 Tegnet K. Olsen Ockelmann 197” and on reverse “L.G.O. stn 49 1957; 56°43′ S, 27°41′ W, 1497f [= 2737m]” (NHMD-1175747) ( Fig. 11A–C View Fig ); 1 dry shell labelled “ Thyasira subovata (Jeffreys) L.G.O. stn 49 Tegnet K. Olsen Ockelmann 1971” and on reverse “L.G.O. stn 49, 1957, 56°43′ S, 27°41′ W, 1497f [= 2737 m]” [this latter appears to be the shell in the drawing by K. Olsen and labelled “ subovata S. Atlantic” (NHMD-1175764)]; 1 shell + 5 valves dry labelled “ Axinulus n. sp. ( Th. subovata aff.) L.G.O. stn 49, 1957, 56°43′ S 27°41′ W, 1497f [= 2737 m]” (NHMD-1175751) ( Fig. 11F View Fig ); 1 dry shell labelled “ Thyasira ( Mendicula) ‘ ingolfi ’ n. sp. L.G.O. stn 51, 45°34′ S, 06°02′ E, (2507f) 4585 m ” (NHMD-1175750) ( Fig. 11D–E View Fig ). The distribution of these specimens is shown in Fig. 12. View Fig

L.G.O. stations refer to the Vema expedition of 1957 to the South Atlantic (see Clark 1961). Jørgen Knudsen (1970) noted that, while the bulk of the Vema samples were in the Museum of Comparative Zoology in Harvard, some had been transferred to the Zoological Museum in Copenhagen (now incorporated into the Natural History Museum of Denmark) where presumably Ockelmann had access to them. Knudsen also noted that Ockelmann was working on the Ingolf material but had not published on it. It is rather surprising that no Thyasiridae are included in Knudsen’s (1970) Galathea Reports , although the material in Ockelmann’s possession was most definitely abyssal in origin.

Unfortunately, the specimens from Ingolf stn 36 are partially decalcified and I cannot equate them with the stipple drawings labelled “ ingolfi n. sp.” These specimens are very small, around 1 mm in diameter, but they have a single demibranch and could therefore be a Mendicula or a Leptaxinus . Furthermore, Ockelmann conflated material from Ingolf stn 36 with Vema material from the South Atlantic that he suggested had affinity with T. subovata ( Jeffreys, 1881) . Examination of these shells suggests that South Atlantic shells labelled “ ingolfi n. sp.” are not T. subovata . The South Atlantic shells most closely resemble those of the genus Mendicula and only SEM examination will tell if they could be a species of Adontorhina Berry, 1947 . Without the shells from Ingolf stn 36 it is not possible to tell whether they are conspecific with the Vema shells from the South Atlantic, and without a larger number of specimens, including those with soft parts, it is not possible to determine whether it is indeed a new species.

Amphi-Atlantic species

In 1959, as an adjunct to his Greenland monograph ( Ockelmann 1958), Ockelmann visited the USNM in Washington to examine the type material in the Jeffreys and Verrill & Bush collections. It must have been a result of this visit that he concluded that some of the American species could also be found in European waters. During this visit, he selected lectotypes and neotypes of a number of species, but he never formally published these designations. Neither did he ever publish descriptions or illustrations comparing American and European examples.

Comparisons with type material are essential to verify synonymy and identifications of amphi-Atlantic species. Many type selections have been validly made, but some have now crept into the literature following their incorporation through the curation of the collections. Ockelmann selected type material from the Jeffreys collection and some have been validly published by Warén (1980), as follows under their original genus:

• Clausina croulinensis Jeffreys, 1847 View in CoL ; neotype USNM 62048 About USNM .

• Axinus incrassatus Jeffreys, 1876 View in CoL ; lectotype USNM 61969 About USNM .

• Axinus planatus Jeffreys, 1882 : not found.

• Axinus polygona Jeffreys, 1864 View in CoL ; not found.

• Axinus rotunda Jeffreys, 1881 View in CoL ; not found, subsequently noted in collection under USNM 61942/a but see under T. granulosa View in CoL below.

• Axinus subovatus Jeffreys, 1881 View in CoL ; syntype USNM 61895 About USNM , subsequently noted as lectotype under USNM 61895 About USNM .

• Axinus succisa Jeffreys, 1876 View in CoL ; lectotype USNM 61973 About USNM .

• Axinus tortuosus Jeffreys, 1881 View in CoL ; lectotype USNM 61904 About USNM and paralectotype USNM 683898 About USNM , but see note by Ellen Strong in USNM catalogue on line: EZID: http://n 2t.net/ark:/65665/3ce7ffe52-e280-48e9-a33c-2423b208bff0 .

Although not cited in the USNM on-line catalogue, Ockelmann was responsible for selecting lectotypes from the Verrill & Bush collection, as indicated on annotations in the collection, but unlike Warén, he never published them:

• Cryptodon obsoletus Verrill & Bush, 1898 View in CoL ; lectotype USNM 159886 About USNM , but this was never published and should be cited as a figured syntype .

• Cryptodon ( Axinulus) pygmaea Verrill & Bush, 1898 ; lectotype USNM 78368 About USNM , but this was never published and should be cited as a figured syntype .

• Cryptodon equalis Verrill & Bush, 1898 View in CoL ; holotype USNM 74302 About USNM , but this was not selected by Verrill & Bush and should be a syntype or figured syntype .

A fourth amphi-Atlantic species to be confirmed by Ockelmann was Thyasira gouldii View in CoL , originally described as Lucina gouldii Philippi, 1845 ( Philippi 1845a). No type specimens have been isolated and there is no record of them in the MCZ in Harvard ( Coan & Kabat 2017). Ockelmann did not visit the MCZ and we assume his concept of this species was based on material in the USNM.