Paraconularia planicostata (Dawson, Reference Dawson1868) is one of two species in this genus (Sinclair, Reference Sinclair1940) of conulariid cnidarian currently known from Mississippian strata in the Maritimes Basin in Atlantic Canada (Babcock and Feldmann, Reference Babcock and Feldmann1986). A salient characteristic of the species is the presence of a low and narrow internal carina at or near the longitudinal midline of each of the four faces of the gently tapered periderm (Van Iten et al., Reference Van Iten, Tollerton, Ford and Hunter2020). Paraconularia planicostata occurs in marine carbonates in the Upper Mississippian lower Windsor and lower Codroy groups in Nova Scotia and western Newfoundland, respectively (e.g., Bell, Reference Bell1929; Stacy, Reference Stacy1953; Dix and James, Reference Dix and James1988; Boehner et al., Reference Boehner, Giles, Murray, Ryan, Geldsetzer, James and Tebbutt1989; Boehner and Prime, Reference Boehner and Prime1993; Lavoie and Sami, Reference Lavoie and Sami1998; Jutras et al., Reference Jutras, Ryan and Fitzgerald2006; Ryan and Giles, Reference Ryan, Giles, MacDonald and MacDonald2017; Van Iten et al., Reference Van Iten, Tollerton, Ford and Hunter2020). The species is exceptionally abundant, with richly fossiliferous biohermal limestones containing up to approximately 20 specimens per 1000 cm³ of host rock (Van Iten, unpublished observations)—a volumetric density matched by few other conulariid-bearing rock units.

There are five previously figured type specimens of Paraconularia planicostata, all from unspecified members and formations in the lower Windsor Group of Nova Scotia (Fig. 1). However, only the holotype specimen and an unnumbered plastoholotype are listed as type material of P. planicostata in the most recent description of the species (Babcock and Feldmann, Reference Babcock and Feldmann1986). The four additional specimens comprise two hypotypes and two plesiotypes, three of which (one hypotype and two plesiotypes) are included in the synonymy of Babcock and Feldmann (Reference Babcock and Feldmann1986). According to the International Code of Zoological Nomenclature (ICZN, 1999), a plesiotype is a specimen used in the redescription of an existing species (Foote and Miller, Reference Foote and Miller2007), while a hypotype, although not currently recognized in the ICZN, has previously been understood to be a figured specimen collected after the publication of the original description of the species it represents. The hypotype specimen not included in the synonymy of Babcock and Feldmann (Reference Babcock and Feldmann1986) has been transferred from its original repository and given a new catalogue number. The purpose of the present taxonomic note is thus to update and clarify the repositories, catalogue numbers, and locality and stratum of all five, previously designated type specimens of P. planicostata.

Figure 1. Light photographs of the previously designated holotype, hypotype, and plesiotype specimens of Paraconularia planicostata (Dawson, Reference Dawson1868) from the lower Windsor Group (Upper Mississippian, mid–late Visean) of central Nova Scotia and Cape Breton Island, Atlantic Canada. All specimens oriented with the apertural (oral) end at the top. (1) Holotype RM(MU) 2749; (2) hypotype NSM023GF017.141; (3) hypotype GSC 21767; (4) plesiotype GSC 7672a; (5) plesiotype GSC 7672. Scale bar = 5 mm.

The holotype specimen, originally described and figured in an unscaled line drawing (Dawson, Reference Dawson1868, Reference Dawson1878, Reference Dawson1891, fig. 117), before the advent of the holotype concept (Schuchert, Reference Schuchert1897), is still housed in the paleontological type collection of the Redpath Museum at McGill University, Montréal, Québec (catalogue number RM(MU) 2749; see also Alison and Carroll, Reference Alison and Carroll1972; Babcock and Feldmann, Reference Babcock and Feldmann1986, fig. 27.1–27.4; Fig. 1.1). The hypotype specimen not included in the synonymy of Babcock and Feldmann (Reference Babcock and Feldmann1986) was originally figured (but not described) by Moore and Ryan (Reference Moore and Ryan1976, pl. V, fig. 10), who identified it, correctly, as P. planicostata (Dawson). This specimen (Fig. 1.2) was first housed in the paleontological collections of the Department of Earth and Environmental Science of Acadia University at Wolfville, Nova Scotia, under catalogue number 2141. It then was transferred from Acadia University to the Nova Scotia Museum of Natural History in Halifax, where it was renumbered NSM023GF017.141. This transfer and renumbering is reported here for the first time.

The other three type specimens are housed in the paleontological collections of the Geological Survey of Canada in Ottawa, Ontario. The hypotype, GSC 21767, was first illustrated (but not described) in Bamber and Copeland (Reference Bamber, Copeland and Douglas1970, pl. XV, fig. 3; incorrectly cited as Bamber and Copeland, Reference Bamber, Copeland and Douglas1976, in Babcock and Feldmann, Reference Babcock and Feldmann1986) and is illustrated here in Figure 1.3. The plesiotypes, GSC 7672a and GSC 7672, were first illustrated in Bell (Reference Bell1929, pl. XXXII, figs. 1 and 2) and are figured here in Figure 1.4 and 1.5. Together with Dawson's (Reference Dawson1868) original description, Bell (Reference Bell1929, p. 99) provided detailed descriptions of the two plesiotype specimens in his section titled “remarks.” These three specimens, originally identified as Conularia planicostata, were included in the synonymy of P. planicostata by Babcock and Feldmann (Reference Babcock and Feldmann1986), who therefore recognized them as belonging in this genus and species. Curiously, GSC 21767 is not listed as a type specimen in Bamber and Copeland (Reference Bamber, Copeland and Douglas1970), even though the official GSC collection label accompanying the specimen designates it as a hypotype. Thus, the status of GSC 21767 as a hypotype specimen of P. planicostata is announced here for the first time.

The holotype (RM(MU) 2749) and two hypotypes (NSM023GF017.141 and GSC 21767) were collected at Irish Cove in southwestern Cape Breton County, Cape Breton Island, Nova Scotia (Dawson, Reference Dawson1868, Reference Dawson1878, Reference Dawson1891; Bamber and Copeland, Reference Bamber, Copeland and Douglas1970; Moore and Ryan, Reference Moore and Ryan1976; Fig. 2). The two plesiotypes (GSC 7672 and 7672a) were discovered near the town of Windsor, central Nova Scotia (M. Coyne, written communication, 2023), and thus they may have been collected from the Avon River and/or Miller's Quarry localities of Bell (Reference Bell1929). The stratigraphical provenance of the plesiotypes is also uncertain but could be one or two of several formations in the Windsor–Kennetcook Sub-basin (see Waldron et al., Reference Waldron, Giles and Thomas2017). Specimens from Irish Cove occur in the biohermal B₁ limestone member of the late Visean (Asbian) Enon Formation (P.S. Giles, written communication, 2023; see also Stacy, Reference Stacy1953, Boehner and Prime, Reference Boehner and Prime1993, and Waldron et al., Reference Waldron, Giles and Thomas2017), which is exposed along about 250 m of the southern shore of Bras d'Or Lake, immediately northwest of Lakeshore Drive (Fig. 2). Interestingly, Barr and White (Reference Barr and White2017) mapped this limestone as belonging in the Hood Island Formation, which is slightly younger (Brigantian) than the Asbian Enon Formation (Waldron et al., Reference Waldron, Giles and Thomas2017). However, this interpretation is not supported by faunal evidence, which, while placing the Irish Cove limestone in the B macrofaunal zone of Bell (Reference Bell1929) and subsequent authors (P. S. Giles, written communication, 2023), places the Hood Island Formation in the C macrofaunal zone (Waldron et al., Reference Waldron, Giles and Thomas2017).

Figure 2. Geological map of Irish Cove and surrounding area (modified after Barr and White, Reference Barr and White2017). Location in UTM coordinates in Easting and Northing ×1000. Inset shows Cape Breton Island with red box showing map location.

In conclusion, then, Irish Cove (Fig. 2) may be designated as the type locality of P. planicostata, even though Dawson (Reference Dawson1868, Reference Dawson1878, Reference Dawson1891) listed the species as being present at this locality as well as at Windsor and Shubenacadie, two towns in central Nova Scotia. The type stratum, never previously designated at the level of member or formation, may now be listed as the B₁ Member of the Enon Formation (lower Windsor group).