Ebala species [read on]

         Careliopsis octona sensu Jong and Coomans, 1988 (131; sp. no. 680; pl. 21, fig. 680) not Turbonilla (Eulimella) [sect. Stylopsis] octona of Guppy in Guppy and Dall, 1897 (317; pl. 27, fig, 6); see fig. 1 below.
         Ebala resticula sensu Deng, 2011 (165-166; sp. no. 638; figs. 638) not Eulimella (Stylopsis) resticula of Dall, 1889 (338 [unfigured]); see fig. 2 below.
         Bacteridium bermudense sensu Redfern, 2013 (246; sp. no. 693; figs. 693A, B) not Turbonilla (Careliopsis) bermudensis of Dall and Bartsch, 1911 (279; pl. 1, fig. 4); see fig 3 below.

Ebala species

 Beach drift, Billy's Bay, St. Elizabeth Parish, Jamaica (1.9 mm) . Digital images by David Kirsh.

Review of the ORIGINAL descriptions and available authentic figures illustrations (see Figs 1-3) of the three species indicated above reveals very similar heteroaxial hyperstrophic protoconchs but shells otherwise distinguishable from the specimen figured above, which was collected by David. The fossil taxon Turbonilla (Stylopsis) octona (Fig. 1) is a smooth shell with rather similar oblique sutures, but the broader initial whorls differ significantly. Both Eulimella (Stylopsis) resticula and Turbonilla (Careliopsis) bermudensis of Dall and Bartsch, 1911 (Figs. 2 and 3 respectively) have a less attenuated profile, less oblique sutures, and a distinct spiral sculpture. These three and David Kirsh's shell above, which seems to have been misattributed to each of them in the literature, belong in the either the murchisonellid/ebaline genus Ebala Gray, 1847 [Type species (TS) Turbo nitidissimus Montagu, 1803 by original monotypy (OM)] or the pyramidellid genus Bacteridium Thiele, 1929 [TS Eulimella praeclara Thiele, 1925 OM]* rather than the pyramidellid genera Careliopsis [e.g., <http://www.jaxshells.org/1002xx.htm>], Eulimella, Stylopsis, or Turbonilla to which they'd been variously assigned over the years.

* These two genera, Ebala and Bacteridium, while not very closely related phylogenetically have "astonishingly similar shells" and can only be distinguished by the presence of a bizarre "jaw apparatus" characteristic of the murchisonellids (Warén, 1994).


Redfern (loc. cit.) describes the holotype of Turbonilla (Careliopsis) bermudensis of Dall and Bartsch, 1911 as smooth and believes the original description (above) was based on another specimen in USNM 221614 citing Absalão and Pimenta (2001). This lot originally contained three specimens according to the authors but presently two per the USNM catalogue at <
http://collections.nmnh.si.edu/search/iz/>, which does not include a specimen image. However, a review of Absalão and Pimenta (2001: 43; figs. 1-4) confirms Redfern's position as well as the synonymy of Turbonilla bartschi Aguayo and Rehder, 1936 based on figures of their respective holotypes. Thus David's shell may be placed securely with this species.

That's not all: while the Brazilian workers found no spiral sculpture on the holotypes of these two taxa, they did on the holotype of Turbonilla (Stylopsis) octona Guppy in Guppy in Dall, 1897 and synonymized it with Eulimella (Stylopsis) resticula Dall, 1889 refuting two or the three original descriptions above. All the preceding observations demonstrate the folly of total reliance of original descriptions (and figures) in proper taxonomy!

Redfern (loc. cit., sp. 694; 5 figures) also treats an un-named Ebala, which species appears to be identical to Pliocene material from the Pinecrest beds of the Upper Tamiami Formation, Sarasota Co., FL. See <http://www.jaxshells.org/resta.htm>, where the image of a Recent specimen of E. resticula is also posted. Thus we - as well as Redfern (2013) - have accounted three species of Ebala (or Bacteridium, or, perhaps between the two genera) in W Atlantic waters.

A shell image (reproduced below as Fig. 4) putatively (and incorrectly) captioned Bacteridium resticulum as treated by the World Register of Marine Species (WoRMS <http://www.marinespecies.org/aphia.php?p=taxdetails&id=420472>) appears to belong in a separate genus, perhaps Falsoebala Gründel, 1998 [see Falsoebala species Fossil] and is probably undescribed.

HGL 1 January, 2018

Dall, W. H., 1889. Reports on the results of dredgings, under the supervision of Alexander Agassiz, in the Gulf of Mexico (1877-78) and in the Caribbean Sea (1879-80), by the U. S. Coast Survey Steamer 'Blake.' Bulletin of the Museum of Comparative Zoology 18: 1-492, pls. 10-40. 8 June. <http://www.biodiversitylibrary.org/item/25505#page/5/mode/1up>

Dall, W.H. and P. Bartsch. 1911. New species of shells from Bermuda.  Proceedings of the United States National Museum 40(1820): 277-288, pl. 35. 8 May. <http://www.biodiversitylibrary.org/item/53820#page/363/mode/1up>

deJong, K.M. and H.E. Coomans, 1988. Marine gastropods from Curaçao, Aruba and Bonaire. Studies on the Fauna of Curaçao and other Caribbean Islands 69: 1-261, 47 pls

Deng Yan Zhang, 2012. Antiguan Shallow-water Seashells A collection with 18 years study and research of shoreline shells from Antigua and West Indies. MdM Publishing, Wellington, FL. xi + 1-(211).+ 22 item errata sheet. March.

Guppy, R.J.L and W.H. Dall, 1896 Descriptions of fossils from the Antillean region. Proceedings of the United States National Museum 19: 303-331, pls. 27-30. <http://www.biodiversitylibrary.org/item/31780#page/371/mode/1up>

Pimenta, A.D. and R.S. Absalão, 2001. The genera Bacteridium Thiele, 1929 and Careliopsis Mörch, 1875 (Gastropoda: Pyramidellidae) from the east coast of South America. Bollettino Malacologico 37(1-4): 41-48.

Redfern, C., 2013. Bahamian Seashells: 1161 Species from Abaco, Bahamas. Bahamianseashells.com, Inc: Boca Raton, FL. 501 pp.

Warén, A., 1994 Systematic position and validity of Ebala Gray, 1847 (Ebalidae fam. n., Pyramidelloidea, Heterobranchia. Bollettino Malacologico 30(5-9): 203-210. 30 Nov. <https://biodiversitylibrary.org/page/49937818>

Stylopsis] octona

Eulimella (Stylopsis) resticula

Turbonilla (Careliopsis) bermudensis