Phylum Brachiopoda
Subphylum Lingulifomea - Class Lingulata
Order Lingulida
Discina sp. Lamarck, 1819 - Description from Holmer and Popov, 2000
Description: Shell is irregularly subcircular and biconvex to convexoconcave. The ventral valve is cemented to substrate and the pedicle opening may be sealed in adults. Both valves have a subcentral apex. Shell has an ornament of concentric growth lines and fine costellae. The ventral interior has a high subtriangular median septum (probably attachment site of oblique internal muscle) extending a short distance posterior of the apex, partially closing pedicle opening, and almost forming pedicle tube. The lophophore is spiralophous.
Ecology: Epifaunal, filter feeders that attach by a highly muscular pedicle to some hard substrate.
Lingula attenuata
Description:
Ecology: Infaunal burrowers and filter feeders.
Lingula curta Conrad, 1842 – Description from Grabau and Shimer, 1907 and Wilson, 1946
Lingula curta Conrad, 1842, p. 266, pl. 15, fig. 12; Hall, 1847, p. 97, pl. 30, fig. 6; Billings, 1863, p. 161, fig. 138; Grabau and Shimer, 1907, p. 195; Wilson, 1946, p. 18, pl. 1, fig. 4.
Description: Shell is small, obtusely ovate, and depressed convex. Length and width nearly equal, front is broadly rounded, and the shell outline is subcircular except for a slight irregularity at the beak. Beak is projected beyond the end of the margin of the shell. Surface is covered by elevated concentric growth lines.
Ecology: Infaunal burrowers and filter feeders.
Lingula daphne Billings
Description:
Ecology: Infaunal burrowers and filter feeders.
Lingula elongata Hall, 1847 – Description from Wilson, 1946
Lingula elongata Hall, 1847, p. 97, pl. 30, fig. 5; Billings, 1863, p. 161, fig. 135; Wilson, 1946, p. 18, pl. 1, fig. 5.
Description: Near parallel sides, a lack of radial striae, and a great convexity characterize this species.
Ecology: Infaunal burrowers and filter feeders.
Lingula obtusa Hall, 1847 – Description from Wilson, 1946
Lingula obtusa Hall, 1847, p. 98, pl. 30, fig. 7; Billings, 161, fig. 137, Wilson, 1946, p. 10, pl. 1, fig. 3.
Description: An obtuse angle of the beak and a non-terminal position characterize this species.
Ecology: Infaunal burrowers and filter feeders.
Lingula quadrata Sowerby
Description:
Ecology: Infaunal burrowers and filter feeders.
Lingula rectilateralis major Ruedemann, 1925 – Description from Wilson, 1946
Lingula rectilateralis Emmons, 1842, p. 399, fig.6; Grabau and Shimer, 1907, p. 195, fig. 288c; Ruedemann, 1912, p. 91, pl. 4, fig. 1
Lingula quadrata Hall, 1847, p. 96, pl. 30, fig. 4, p. 285, pl. 29, fig. 1.
Lingula rectilateralis major Ruedemann, 1925, p. 110, pl. 11, fig. 1, 2.
Description: Shell is large with nearly parallel sides and has an elliptical form. The front of the shell is regularly rounded and the anterior margin is more or less truncated. Surface is marked by radiating striae.
Ecology: Infaunal burrowers and filter feeders.
Lingula riciniformis Hall, 1847 – Description from Wilson, 1946
Lingula riciniformis Hall, 1847, p. 95, pl. 30, fig. 2; Winchell and Schuchert, 1893, p. 343, fig. 24, pl. 29, fig. 9; Wilson, 1946, p. 20, pl. 1, fig. 2.
Description: Shell is 6 mm to 8 mm in length. Has an even convexity and a somewhat attenuated posterior part ending in an obtuse beak.
Ecology: Infaunal burrowers and filter feeders.
Leptobolus sp? - Description from Holmer and Popov, 2000
Description: Shell is small, elongate, and oval. Has ventral pseudointerarea with deep triangular pedicle groove. The ventral visceral area is thickened anteriorly, bisected by median ridge, and bifurcates near the anterior end. Dorsal visceral area has one to three low ridges.
Ecology: Infaunal burrowers and filter feeders.
Schizocrania filosa Hall, 1847 – Description from Wilson, 1946
Orbivula (?) filosa Hall, 1847, p. 99, pl. 30, fig. 9.
Schizocrania filosa Hall. Hall and Whitfield, 1875, p. 73, pl. 1, figs. 12-15; Hall and Clarke, 1892, p. 143, pl. 4, figs. 22-30; Bassler, 1915, p. 1144; Foerste, 1920, p. 202; Wilson, 1946, p. 23, pl. 2, figs. 17, 18; Cooper, 1956, p. 275, pl. 19, figs. 20, 21.
Description: Shell is subcircular in outline. The pedicle valve is flat or convex and apex is subcentral. Pedicle notch is deep and wide with its apical angle occupied by a plate. The brachial valve is larger than the pedicle valve and is convex with a terminal beak and two sets of muscle scars on the interior. One pair of strong posterior adductor scars are separated by a low median ridge, diverging from the beak and in some cases faintly divided transversly and a second pair of faint, minute scars are centrally placed. The surface of pedicle valve is concentrically wrinkled and the surface of the brachial valve is radially striated. Can be distinguished from other Ordovician brachiopods by the fine thread-like striae and the terminal beak on the brachial valve.
Ecology: Epifaunal, filter feeders that attach by cementation to some hard substrate. Substrate is often another organism’s shell. Schizocrania has been found cemented to conularids (Harland and Pickerill, 1987) and to orthoconic nautiloids (Lockley and Anita, 1980).
Trematis terminalis (Emmons, 1842) – Description from Wilson, 1946
Orbicula terminalis Emmons, 1842, p. 395, fig. 4.
Trematis terminalis (Emmons). Sharpe, 1848, p. 68, figs. 1-3; Emmons, 1855, p. 201, fig. 63, pl. 8, fig. 11; Wilson, 1946, p. 23, pl. 1, figs. 18a, b.
Description: Shell varies from 8.5 mm to 15 mm in length and from 10 to 13 mm in width. The brachial valve is gently convex with very fine concentric striae. Punctae penetrate the inner shell where they are comparatively distant and have a quincuncial rather than a radial arrangement. The punctae of the outer surface is in quincunx arrangement, but becoming crowded and out of either radial or concentric alinement near the anterior. This species differs from most other species in the quincuncial arrangement of the punctae.
Ecology: Epifaunal, filter feeders that attach by cementation to some hard substrate. Substrate is often another organism’s shell.
Order Acrotretida
Conotreta rusti Walcott, 1889 – Description from Walcott, 1889
Conotreta rusti Walcott, 1889, p. 365, figs. 1-4; Hall and Clarke, 1892, p. 104, pl. 4, figs. 16-21; Cooper, 1956, p. 254, pl. 16, fig. 41.
Description: Larger or dorsal valve more or less acutely conical, rounded to subtriangular at the margin of the valve. The false area is nearly flat, narrow and grooved at the center by a longitudinal, narrow, shallow furrow. Surface of shell is marked by concentric growth lines that pass uninterruptedly over the false area. The cast of the interior of the conical valve show six narrow, elongate ridges radiating from the apex that separate five depressions on the sides and front of the shell. With this structure the interior of the shell would have five radiating ridges gradually widening out from the apex and becoming hollow towards their outer ends. The cast of the interior of the shell, near the apex, shows that one of the ridges joined a thicken portion of the shell, probably as the support for the siphonal tube.
Order Siphonotretida
Siphonotreta sp. deVerneuil, 1845 - Description from Holmer and Popov, 2000
Description: Shell is ventri- or equi-biconvex, elongate oval, and ornamented with undulating fila superposed on thick, widely spaced lamellae with closely spaced, evenly distributed short spines of uniform size. The foramen is circular and apical. Ventral pseudointerarea are large, apsacline, orthocline to anacline, undivided, and flattened, with concave median depression. The dorsal pseudointerarea are orthocline, shelflike, and fit closely into the median depression in ventral pseudointerarea. Median groove is wide, poorly defined, with propareas reduced. The visceral area of both valves is thickened and forms platforms. Internal pedicle tube long, possibly closed in adults, and emerges through the visceral platform, with a possible umbonal muscle scar. The dorsal anterior lateral muscle scars are placed between central muscle scars, and are bisected by a low median ridge.
Subphylum Craniformea - Class Craniata
Order Cranida
Crania trentonensis (?) Hall, 1866 – Description from Wilson, 1946
Crania trentonensis Hall, 1866, p. 12; Hall, 1872, p. 219, pl. 7, figs. 11, 12; Hall and Clarke, 1892, pl. 4, figs. 21, 22; Wilson, 1946, p. 26, pl. 2, fig. 10.
Description: Shell is small and subcircular with the posterior part slightly wider. The pedicle valve is flat, depressed convex or conforming to the host it attaches to, and lacks a pedicle opening. Brachial valve is convex, with the apex subcentral, and is posteriorly directed. The surface is smooth, spinose, and characterized by its strong concentric growth lines. Interior of both valves has two pairs of adductor scars, the posterior pair close to the margin and widely separated form one another, and the anterior pair smaller and near the center. The shell is calcareous and strongly punctate with the canals dividing near the surface.
Ecology: Epifaunal, filter feeders that cement by the entire surface of the ventral valve to a hard substrate. Substrate is often another organism’s shell.
Subphylum Rhynconelliformea - Class Strophomenata
Order Strophomenida
Leptaena sp. Dalman, 1828 - Description from Cocks and Rong Jia-yu, 2000
Description: Shell outline is usually transverse and rounded anteriorly. The profile is concavoconvex with sharp anterior dorsal geniculation. Has a shell ornament of costellate to unequally parvicostellate. Concentric rugae are variable, but usually well developed. Has a small pseudodeltidium, a large chilidium and short dental plates. The ventral muscle field varies from subcircular to elongate with bounding ridges usually developed posterolaterally, sometimes curving round anteriorly. Cardinal process lobes are elongate and ventrally directed with socket ridges present, but usually weak, and sometimes with crenulations. The dorsal muscle field is variably impressed with median ridge often present and transmuscle ridges, diaphragm variably developed in dorsal valve.
Ecology: Epifaunal, filter feeders that attach to a hard substrate by a pedicle, which protrudes through the foramen in the ventral valve.
Rafinesquina trentonensis (Conrad) – Description from Salmon, 1942
Leptaena alternata Conrad, 1838, p. 115; Hall, 1847, p. 102, pl. 31, fig. 1a-c, pl. 31A, figs. 1d-e.
Strophomena alternata Conrad, 1839, p. 63; Conrad, 1840, p. 201; Conrad, 1841, p. 37; Emmons, 1842, p. 395, fig. 3; Owen, 1844, p. 366, fig. 3; Emmons, 1855, p. 197, pl. 11, fig. 3, pl. 17, fig. 2; Billings, 1856, p. 204, fig. 3; Hitchcock, 1861, p. 293, fig. 199; Lesley, 1890, p. 1121, figs.
Orthis alternata Emmons, 1842, pp. 182, 319.
Orthis plana Castelnau, 1843, p. 38, pl. 14, fig. 1.
Orthis huroniensis (?) Castelnau, 1843, p. 37, pl. 14, fig. 6.
Strophomena angulata (?) Owen, 1844, pl. 18, figs. 1, 3.
Leptaena trentonensis Conrad MS. Hall, 1847, p. 102.
Rafinesquina alternata (Conrad), Hall and Clarke, 1892, p. 282, pl. 8, figs. 6-11, 27, 28, pt. 2, 1895, pl. 84, figs. 17, 18; Winchell and Schuchert, 1893, p. 404, pl. 31, figs. 32-33, 34; Cumings, 1908, p. 926, pl. 37, fig. 1b;Wilson, 1946, p. 66, text-fig. 1, no. 3, pl. 5, fig. 4.
Rafinesquina trentonensis (Conrad). Salmon, 1942, p. 574, pl. 85, figs. 1-10; Cooper, 1956, p. 888, pl. 247B, figs. 5, 6, pl. 266 E, fig. 17; Rice, 1987, p. 158, pl. 4. fig. 9; Emerson, 2002, p. 362.
Description: Shell wider than long, broadly U-shaped in outline with greatest width at or near the hinge line. Cardinal angles are usually rectangular, but may show small ears or may be slightly obtuse. The lateral margins are usually straight and parallel. When the cardinal angles are auriculate, the lateral margins are faintly sinuate anterior to the ears. The anterolateral and anterior margins form a broad, smooth curve, varying only slightly from perfectly semicircular.
Ecology: Epifaunal, filter feeders that lie free on the soft substrate, possibly on a muddy sand or silt substratum.
Sowerbyella curdvillensis (Foerste, 1912) – Description from Titus, 1992
Plectambonites curdsvillensis Foerste, 1912, p. 122, pl. 10, figs. 15a, 15b; Mather, 1917, p. 39, pl. 1, figs. 12, 13; Willard, 1928, p. 275-276.
Plectambonites punctostriatus Mather, 1917, p. 38-39, pl. 1, figs. 15-17.
Sowerbyella punctostriata (Mather, 1917). Wilson, 1946, p. 51, pl. 3, fig. 24; Cooper, 1956, p. 792-793, pl. 205C, figs. 9-25, pl. 206D, figs. 14, 15.
Sowebyella monilifera Cooper, 1956, p. 785, pl. 199A, figs. 1-8, pl. 206 E, figs. 16-28.
Sowerbyella curdsvillensis (Foerste, 1912). Cooper, 1956, p. 780-781, pl. 201A, figs. 1-13; Rice, 1987, p. 156, pl. 3, fig. 1; Titus, 1992, p. 769, figs. 4, 6; Emerson, 2002, p. 365, pl. 1, fig. 7.
Description: Adults are14 to 22 mm in width. Pedicle valve convexity shows medial fold or is flattened in some facies, rounded pedicle valves of low convexity found in all facies. Costellae are fine and straight with 3 to 4 fine ones between two coarser ones. Punctae are abundant and cardinal extremities are alate or rectangular in some facies. Rugae are rare on cardinal processes and pedicle interiors rarely seen. Brachial valve interiors are variable. Some forms are quite ornate with submedial septa, muscle scars, subperipheral thickening, and vascular markings while others are less well sculpted. The brachial exteriors display moderate concavity and simple, straight costellae.
Ecology: Epifaunal, filter feeders that lie free on the soft substrate, possibly on a muddy sand or silt substratum.
Sowerbyella sericea (Sowerby, 1839) – Description from Wilson, 1946 and Bretsky, Flessa, and Bretsky, 1969
Leptaena sericea Sowerby, 1839, p. 636, pl. 19, figs. 1, 2.
Plectambonites sericeus (Sowerby, 1839). Hall and Clarke, 1892, pl. 15, figs. 15-19.
Sowerbyella sericea (Sowerby, 1839). Jones, 1928, p. 414, pl. 21, figs. 1-4; Wilson, 1946, p. 51, pl. 3, fig. 26.
Description: Shell is medium size, wider than longer, and gently to strongly concavo-convex. Outline is subquadrate or semicircular and cardinal angles are slightly acute. There are fine, primary, secondary, and tertiary striae, differentiated in size on the pedicle valve, but more equal on the brachial valve. A few wrinkles are present along the hinge line in some cases. The pedicle valve interior has well-defined dental lamellae, two elongate-oval muscle scars extending halfway to the anterior and a median septum 2 mm to 3 mm in length with prongs at right angle to one another forming the inner side of the muscle scar. The brachial valve has short divergent crural plates, two prominent subparallel septa originating just anterior to the cardinal process and forming the inner side of the muscle scar.
Ecology: Epifaunal, filter feeders that lie free on the soft substrate, possibly on a muddy sand or silt substratum.
Class Rhynchonellata - Order Orthida
Suborder Orthidina
Dalmanella testudinaria (Dalman, 1828) – Description from Williams and Wright, 1963
Orthis testudinaria Dalman, 1828, p. 115, pl. 2, figs. 4a-e.
Dalmanella testudinaria (Dalman, 1828). Williams and Wright, 1963, p. 29, pl. 2, figs. 7, 8, 11-13, 16-19; Temple, 1965, p. 383, pl. 3, figs. 1-7, pl. 4, figs. 1-6, pl. 5, figs. 1-7, pl. 6, figs. 1-7; Bergström, 1968, p. 8, pl. 2, fig. 5; Havlíček, 1977, p. 137, pl. 32, figs. 1-15, 18, 19, 23, pl. 56, fig. 13; Nikitin in Appollonov et al., 1980, p. 38, pl. 12, figs. 1-17; Cocks, 1982, p. 760, pl. 79, figs. 4-12.
Description: Shell is ventri-biconvex, subciruclar with a sulcate brachial valve. Shell ornamentation is costellate with 3 ribs per mm at a distance of 5 mm anterior to the dorsal beak. Cardinal process has an undifferentiated bilobed myophore and a shaft anteriorly merging into the median ridge. Fulcral plates and crural pits are present.
Ecology: Epifaunal, filter feeders that attach to a soft substrate (muddy sand or silt substratum) by a pedicle, which protrudes through the foramen in the ventral valve.
Orthis sp. Dalman, 1828 - Description from Williams and Harper, 2000
Description: Shell is large, planoconvex to weakly concavoconvex, rectimarginate, costate, and capillate. The ventral muscle scar is suboval. Brachiophores are widely divergent rods and the ventral vascula media parallel proximally.
Ecology: Epifaunal, filter feeders that attach to a soft substrate (muddy sand or silt substratum) by a pedicle, which protrudes through the foramen in the ventral valve.
Platystrophia amoena McEwan, 1919 - Description from Raymond, 1921
Platystrophia amoena McEwan, 1919, p. 412, pl. 43, figs. 1-8; Raymond, 1921, p. 17, pl. 6, figs. 1-5, 11; Wilson, 1946, p. 32, pl. 3, figs. 7a, b;; Emerson, 2002, p. 396, pl. 3, fig. 1.
Description: Shell below the average size for the genus, the valves moderately and subequally convex, the plications not coarse, and especially at the sides, rather sharp; those on the fold often more broadly rounded. The greatest width is at the hinge, the cardinal angles usually projecting a little even in old specimens. The sinus is shallow, flat-bottomed, or slightly concave, the fold very slightly elevated and with a gently convex or flat crest. The great majority of specimens have three plications in the sinus and four on the fold. The median plication in the sinus is often noticeably stronger than the others, and there is a corresponding median furrow on the fold separating the two pairs of plications. There may be as many as six plications in the sinus and seven on the fold, but such specimens are unusual. The number on each side of the fold and sinus is variable. There may be from seven to ten on the brachial and eight to eleven on the pedicle valve; nine on one valve and ten on the other seems the most common number.
Ecology: Epifaunal, filter feeders that attach to a hard or soft substrate by a pedicle, which protrudes through the foramen in the ventral valve.
Platystrophia biforata Schlotheim
Description: Considered to be a synonym of Platystrophia amoena (Wilson, 1946 and Cooper, 1956).
Ecology: Same ecology as Platystrophia amoena.
Platystrophia biforata var. lynx Eichwald
Description: Considered to be a synonym of Platystrophia amoena (Wilson, 1946 and Cooper, 1956).
Ecology: Same ecology as Platystrophia amoena.
Order Rhynchonellida
Rhynchonella capase - Description of Genus from Owen and Manceñido, 2002
Description: Shell is small to medium in size, subtriangular, gibbous, and nearly convexiplane and cynocephalous. Has a high dorsal fold, and a ventral sulcus that is somewhat flattened. Costae are few and sharp anteriorly. Commissure is uniplicate and acuminate to paucidentate. The beak is small and slight incurved. Dental plates are strong, septalium is shallow, and the dorsal median septum is short. Crura are short and raduliform.
Ecology: Epifaunal, filter feeders that attach to a hard substrate by a pedicle, which protrudes through the foramen in the ventral valve.
Order Atrypida - Suborder Anazygidina
Anazyga recurvirostra (Hall, 1847) – Description from Copper, 1977
Atrypa recurvirostra Hall, 1847, p. 140, pl. 33, fig. 5a-d.
Anazyga recurvirostra (Hall, 1847). Copper, 1977, p. 306, pl. 37, figs. 11-15, text-figs. 5-6.
Description: Shell is small (5 to 7 mm wide), longer than wide, strongly biconvex to ventribiconvex with hypercline beaks. Ribs are fine and evenly sized throughout, though slightly larger flanking the sulcus, averaging about twenty-four in number. Brachial valve is somewhat flattened anteriorly and very faintly sulcate. The pedicle valve is more arched with weak anterior fold. Internally, the pedicle valve is thickened apically with faint median septum, not pedicle constrictions, deltidial plate minute, solid, pointed dorsally, dental cavities elongate, teeth simple, dorso-median projections supported terminally by dorsal wall. The brachial valve has sturdy, short socket plates separated medially by a pit without cardinal process. Crura are extended from small round bases located on inner side of socket plates, diverging laterally at about a 45 degree angle to the mid-shell, then curving inwardly, with spiral whorls beginning at anterior-most portion. Jugum in broad V-shaped band joined anterior to spiralial apex. Two to three spiral whorls present with axes directed medially.
Ecology: Epifaunal, filter feeders that attach to a hard substrate by a pedicle, which protrudes through the foramen in the ventral valve.
Zygospira modesta (Say in Hall, 1847) – Description from Copper, 1977
Atrypa modesta Say in Hall, 1847 pp. 141-142, pl. 33, fig. 15.
Zygospira modesta (Say in Hall). Copper, 1977, p. 303, pl. 37. figs. 1-8, text-figs. 3-4.
Description: Shell moderately sized, wider than long, and planoconvex to weakly biconvex with 15-18 ribs over all. Has 4 strong mid-ribs on the pedicle valve, and 3 corresponding mid-ribs on the brachial valve and the remaining lateral ribs decreasing in size posteriorly. Average width is 8.1 mm, length is 7.2 mm, and depth is 3.9 mm. Internally shell is thin and weak, irregular pedicle collar structures line pedicle cavity. The dental cavities are distinct with teeth near horizontal in the sockets. Has small nodular crural bases on inner socket ridges, crura diverge widely to sides, jugum arising at or near position of cone axes, initially curving postero-medially dorsal to the spiralia, then straightening medially and curving dorso-anteriorly to fuse. Spiralia are D-shaped with straight sides forming a weak V (open anteriorly). No cardinal process observed and dorsal septum is strong. Muscle scars are weakly impressed and poorly known.
Ecology: Epifaunal, filter feeders that attach to a hard substrate by a pedicle, which protrudes through the foramen in the ventral valve. Zygospira modesta has been found attached in clusters by pedicles to stems of crinoids, such as Pycnocrinus (Sandy, 1996). It has also been found attached to bryozoans.
