Umboniinae H. Adams & A. Adams, 1854

Herbert, David G., 2024, The Umboniinae (Mollusca: Gastropoda: Trochidae) of New Caledonia, with descriptions of two new genera and eight new species, plus an additional new species from the Bismarck Sea, European Journal of Taxonomy 973, pp. 1-143 : 5-7

Subfamily Umboniinae H. Adams & A. Adams, 1854 (1840)

Key to genera of Umboniinae in New Caledonia ( Fig. 1 )

Note: this key is based solely on shell characters and is only applicable to the umboniine fauna of New Caledonia. Umboniine species from other areas belonging to these genera may not key out to the correct genus using the features specified.

1. Shell lenticular to subglobose; glossy, later whorls essentially smooth, sculptured only with fine incised spiral striae at most; usually with significant callus deposition on base, associated with columella and umbilical region ( Fig. 1A ).................. Ethalia H. Adams & A. Adams, 1854 (page 7)

– Shell lenticular to elevated turbiniform; lustreless or somewhat glossy, if glossy then sculptured with numerous fine, close-set spiral lirae or with stronger spiral cords .................................................... 2

2. Adult shell small, greatest dimension <4.0 mm; peristome complete or nearly so; lacking an umbilical funicle or thickened peri-umbilical cord ........................................................................... 3

– Adult shell larger, diameter> 4.0 mm; peristome interrupted in parietal region; umbilicus often with a funicle or thickened peri-umbilical cord......................................................................................... 4

3. Shell very small (diameter <2.5 mm), distinctly wider than high....................................................... ..................................................................................................... Ethminolia Iredale 1924 (page 98)

– Shell slightly larger (diameter ± 3.0 mm), diameter and height similar .............................................. ................................................................................................. Vanitrochus Iredale, 1929 (page 121)

4. Shell with conical spire and shallowly indented suture; last adult whorl deep; interior of outer lip with distinct in-running spiral cords; columella lip bearing small nodules; edge of outer lip distinctly notched below periphery ( Fig. 1B ) ............................................... Rossiteria Brazier, 1895 (page 42)

– Shell not as above .............................................................................................................................. 5

5. Spiral sculpture relatively uniform, comprising numerous fine, close-set lirae only, lacking stronger cord-like elements.............................................................................................................................. 6

– Shell not as above .............................................................................................................................. 7

6. Shell small (adult diameter <8.0 mm, usually <6.0 mm); spiral sculpture on spire whorls coarser than on final whorl; umbilical region commonly pale to deep pink, with axial pliculae radiating on to base ............................................................................................ Ethaliella Pilsbry, 1905 (page 92)

– Shell larger (adult diameter up to 14.0 mm); spiral sculpture of more or less even strength throughout; umbilical region variously coloured (white, green-brown, reddish or yellow), but never pink and base lacking distinct axial pliculae ........................... Sericominolia Kuroda & Habe, 1954 (page 54)

7. Shell relatively large (adult diameter>8.0 mm); sculptured with spiral cords and fine axial pliculae; base with broad, thickened peri-umbilical band sculptured with curved pliculae; umbilicus with distinct funicle ( Fig. 1C )................................................................. Talopena Iredale, 1918 (page 71)

– Shell small (adult diameter <7.5 mm); broad periumbilical band lacking, but umbilicus with thickened cord at or just inside its rim, and sometimes with a low funicle within............................ 8

8. Shell glossy; subsutural spiral cord beaded or with raised nodules; umbilical margin angular, with radiating pleats and commonly with peri-umbilical cords ( Fig. 1D ); umbilical funicle lacking......... ......................................................................................................... Tylorhaphe gen. nov. (page 106)

– Shell not as above ............................................................................................................................. 9

9. Shell small and stout (adult diam. <5.0 mm), apex acute; sculpture of distinct spiral cords, two of which stronger (at and just below shoulder), and frequently undulant; umbilicus with a thickened cord just inside its rim, set off from base by shallow groove; funicle weak ( Fig. 1E )...................................................................................... Parminolia Iredale, 1929 (page 35)

– Shell somewhat larger (adult diam. up to 7.5 mm), apex more rounded; spiral sculpture of low cords and finer lirae; thickened cord at rim of umbilicus, somewhat pliculate; funicle more conspicuous with distinct sulcus above ( Fig. 1F ) ..................................................... Kanakina gen. nov. (page 28)

Figures

Fig. 1. Line drawings of shells to show umbilical features discussed in the key to genera; sculptural details of outer base and spire not shown. A. Ethalia H. Adams & A. Adams, 1854. B. Rossiteria Brazier, 1895. C. Talopena Iredale, 1918. D. Tylorhaphe gen. nov. E. Parminolia Iredale, 1929. F. Kanakina gen. nov. Abbreviations: am=angular margin of umbilicus; bc= basal callus; ln= labral notch; nc=nodular columella; pub= peri-umbilical band; puc =peri-umbilical cord; pug =peri-umbilical groove; rp =radiating pleats; s =sulcus; sc =spiral cords; uf =umbilical funicle. Drawings by Linda Davis, not to scale.