Copper and Jin—Ordovidian–Silurian brachiopod evolution, extinction, and recovery
Hindella from the Fraise, Juncliff, and Parastro members. This makes it impossible at this time to name a neotype for the lost H. umbonata “holotype” because the precise collecting locality or horizon is unknown for the extant types. This is left for a later revision, and complete description of all Hindella from the Hirnantian Ellis Bay Formation. Based on our new collections, the exact localties and stratigraphic positions of the three Hindella species from Junction Cliff to Parastrophinella Bluff can, however, be clearly defined.
Occurrence.—In addition to the type locality, collections of Hindella umbonata were also made from the following sites exposing the Juncliff Member: C692 (=C701, A4a). Laloutre road, ~4.2km south of main
road. Light-gray weathering, thin- to medium-bedded micrites to coquinites, with abundant Hindella umbonata, rare Eospir- igerina, Mendacella; middle-upper Juncliff Member. Map 12E/ 13, UTM 20, 53640E, 13150N. C693. Laloutre road, ~4.2km south ofmain road. Lithology
and fauna similar to C692, but ~2m higher stratigraphically. Hindella umbonata less common, more nested; upper Juncliff
Member.Map12E/13, UTM20, 53650E, 13120N. C721 (=A1, A426). Port Menier Quarry at Cap Blanc,
south side of Port Menier, next to shoreline facing Ellis Bay. Light green-gray micrites at top of quarry ( ~3–4m thick), capping recessive shale. Upper 1–2m of quarry section consists of thin-bedded, gray micrite with shaly partings; H. umbonata co-occurs with abundant Barbarorthis and common Menda- cella. Juncliff Member. Map 22H/16, UTM 20, 03120E, 18430N.
A813. Prinsta River, ~1km upstream from mouth, at first
sharp bend to south, north bank; 3–5m thick section, with Hindella umbonata shellbed in recessive blue-gray shale unit, and micrite at 1.45m above a 20 cm thick sandstone bed with giant Hormotoma, corals marking the base of the Lousy Cove Member. Map 12F/5, UTM 20, 73480E, 66540N. A1317b. Lac Cailloux road, 4.8km south of main road; 3m
thick section of light gray, resistant micrite, with Hindella umbonata Juncliff Member. Map 12E/13, UTM 20, 39700E, 14360N.
Remarks.—Hindella umbonata is a common species of the genus on Anticosti Island, and can be readily distinguished from other congeneric species on the island by its larger (average shell width 16mm), strongly elongate, globose shell with par- allel sides. Both H. prinstana and H. bulbusa n. sp. are smaller, with average width of 12mmand 10mm, respectively. Hindella prinstana also has a narrower apical angle, andH. bulbusa n. sp. is pear-shaped (see below).
Hindella prinstana (Billings, 1862) Figure 2.14–2.23
1862 Athyris Prinstana [sic] Billings, p. 145, figs. 122a, b. ?1865 Athyris turgida Shaler, p. 69. 1866 Athyris Prinstana; [sic] Billings, p. 46 (no figures).
1894 Hindella prinstana (Billings); Hall and Clarke, pl. 41, fig. 28, pl. 49, fig. 1 (specimen illustrated from the Fraise Member, in the lower unit at Junction Cliff).
1131
1928 Hindella prinstana (Billings); Twenhofel, p. 220, pl. 22, figs. 12, 13.
1977 Hindella umbonata; Sheehan, pl. 1, figs. 26–28.
Type locality and horizon.—Billings (1862, p. 145) reported the species from “Prinsta Bay, Anticosti, Division 1”, but his original types have not been located. At this locality on the northeast coast, the species occurs in the lower Prinsta Member, stratigraphically coeval to the Fraise Member of the west coast, lower Hirnantian. This low bluff locality on the east side of the Prinsta River mouth (=A135 or A362 of the new collections; map sheet 12F/5, UTM 20, 74480E, 66450N), consists of the following units, in descending order:
(1) 105cm of calcareous sandy shales with rare nodules. (2) 319cm of nodular shale and limestone. Upper 289cm nodular shale and calcarenites with nodules at top, sandy, upper resistant ledge with Hindella prinstana, Hormotoma, and sandstones at 30cm and 95cm above base. Most Hindella occur ~30cm above base at ledge in this 5 cm bed with broken Hindella, aulacerids, cup corals; units less sandy and calcarenitic at base then near top. The base of the western Prinsta Member (=Fraise Member) is at this level.
(3) 145cm nodular, wavy bedded and platy calcareous sandstone (Velleda Member, Vaureal Formation).
Occurrence.—In addition to the type locality, the species occurs in the localities listed below: A134a. Prinsta River mouth, first outcrop on NW bank,
~3m recessive, silty dark green-gray shale and sandstone interbeds at base, overlain by 2m of nodular limestone, with loose valves of Hindella prinstana. Prinsta Member (base). Map sheet 12F/5, UTM 20, 74360E, 66570N. A134b. Prinsta River, NW bank, ~200m upstream, same
stratigaphic level as A134a, with H. prinstana. Map sheet 12F/5, UTM 20, 74130E, 66510N. C717. Jupiter road, ~3km south of main road. Recessive
green-brown soft shales, nodular calcarenites, with abundant Hindella prinstana and Eospirigerina. Fraise Member. Map sheet 12E/11, UTM 20, 69480E, 10370N. A431. Anse aux Fraises. Thinly bedded, dark gray shale,
with nests of Hindella prinstana, Plaesiomys, and Eospirigerina in tidal flat outcrops. Fraise Member, ~15m above base. Map sheet 22H/16, UTM 20, 95660E, 20680N. A432, Anse aux Fraises, tidal flat outcrop, ~150m south of
A431, with localized nests of Hindella prinstana, Parastrophinella, and Leptaena. FraiseMember (middle).Map sheet 22H/16, UTM 20, 95780E, 20430N. A1317a. Lac Cailloux road, 4.8km south of main road,
3–5m lower recessive weathering shales, and brown-green soft to blocky, nodular micrite, with Vellamo, Plaesiomys, and Hindella prinstana. Fraise Member. Map sheet 12E/13, UTM 20, 39700E, 14360N.
Remarks.—There are five species of Hindella in the Ellis Bay Formation, suggesting a relatively rapid evolution of Hindella during the Hirnantian. Other species occur in the higher Para- stro, Prinsta, and Laframboise members. The oldest species, Hindella prinstana is smaller (~12mmwide), and about equally
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