Eubaculites Spath, 1926

Landman, Neil H., 2004, Cephalopods From The Cretaceous / Tertiary Boundary Interval On The Atlantic Coastal Plain, With A Description Of The Highest Ammonite Zones In North America. Part 2. Northeastern Monmouth County, New Jersey, Bulletin of the American Museum of Natural History 2004 (287), pp. 1-107 : 55-70

Genus Eubaculites Spath, 1926

TYPE SPECIES: Baculites vagina Forbes var. ootacodensis Stoliczka, 1866: 199 , pl. 90, figs. 14,?15, by original designation by Spath, 1926: 80.

Eubaculites carinatus ( Morton, 1834) Figures 27–29 , 30A, B , 33U–Y Baculites carinatus Morton, 1834: 44 , pl. 13, fig. 1. Baculites lyelli d’Orbigny, 1847 : pl. 1, figs. 3–7. Baculites tippaensis Conrad, 1858: 334 , pl. 3, fig. 27.

Baculites spillmani Conrad, 1858: 335 , pl. 35, fig. 24.

Baculites sheromingensis Crick, 1924: 139 , pl. 9, figs. 1–3.

Eubaculites lyelli (d’Orbigny, 1847) . Kennedy, 1987: 195, pl. 27, figs. 5–8; pl. 32, figs. 13, 14 (with full synonymy).

Eubaculites carinatus ( Morton, 1834) . Klinger and Kennedy, 1993: 218, text­figs. 7a–e, 21–30, 31a–g, 32– 35, 36e, f, 37, 38, 42a, 52g, h.

Eubaculites carinatus ( Morton, 1834) . Kennedy and Cobban, 2000: 180, pl. 2, figs. 1–23, 27, 28; text­figs. 3, 4 (with additional synonymy). Eubaculites carinatus ( Morton, 1834) . Kennedy et al., 2001: 168, fig. 4a, e.

TYPE: The holotype, by monotypy, is ANSP 72866, the original of Morton, 1834: pl. 13, fig. 1, from the Maastrichtian Prairie Bluff Chalk of Alabama.

MATERIAL: There are 77 specimens, 5 of which are float, from the upper part of the New Egypt Formation and basal part of the Hornerstown Formation, AMNH loc. 3345, Parkers Creek, northeastern Monmouth County, New Jersey, and 1 specimen ( AMNH 47159) from 1.5–2 m below the base of the Hornerstown Formation, AMNH loc. 3346, just upstream from AMNH loc. 3345. All of the specimens are internal molds of fragments less than 75 mm in length. A few specimens retain the original shell material of the septa. There are many more body chamber pieces than phragmocone pieces— there are only four completely septate fragments (5% of the total).

DESCRIPTION: The collection includes both robust and slender forms, presumably macroconchs and microconchs, respectively. These differences are expressed in the angle of taper, although this is also very dependent on ontogenetic stage (table 6). The dorsal onehalf of the flanks are covered with broad, asymmetrically crescentic ribs with a rib index of 2–3. The narrow tabulate venter is serrated with a rib index of 6–8. We describe and illustrate 15 specimens to convey the range of variation of our material.

AMNH 47418 is a piece of body chamber 49.7 mm long with whorl heights of 15.1 and 17.1 mm at the adapical and adoral ends, respectively (fig. 27F–H). The angle of taper is 3.2°. The whorl section at the adoral end is ovoid with maximum width at one­third whorl height both costally and intercostally; the intercostal ratio of whorl width to height is 0.60. The dorsum is very broadly rounded and the dorsolateral shoulder is fairly abruptly rounded. The flanks are broadly rounded and converge to the venter. The narrow, flat venter is bordered by a faint longitudinal groove.

The dorsum shows low, convex folds spaced at distances of approximately 5 mm near the adoral end. There are four large, slightly crescentic nodate swellings on the inner two­thirds of the flanks. The swellings become progressively more widely spaced adorally; the distance between the two most adoral swellings is approximately 14 mm; the rib index is approximately 2. The nodes are strongest just ventral of the dorsolateral margin. The venter is covered by coarse, swollen ribs that show a slight forward projection. They gradually become more widely spaced adorally so that the distance between rib crests at the adoral end of the specimen is approximately 4 mm; the rib index is 6.

AMNH 47506 is a body chamber fragment 56.9 mm long with whorl heights of 11.7 mm and 13.4 mm at the adapical and adoral ends, respectively (fig. 27Q–T). The angle of taper is 3.0°. The ratio of whorl width to height at the adoral end is 0.70. There are low folds on the dorsum. The inner two­thirds of the flanks bear strong crescentic ribs spaced at distances of approximately 10 mm at the adoral end; the rib index is 2.5. The narrow, tabulate venter is ornamented with strong, transverse ribs with a slight adoral projection, producing a serrated appearance; the rib index is 5.

AMNH 47409 is a large fragment of a body chamber 58.2 mm long with whorl heights of 16.7 mm and 19.0 mm at the adapical and adoral ends, respectively (fig. 28H– K). The ratio of whorl width to height at the adoral end is 0.72. The whorl section is ovoid with maximum width at one­third whorl height. The dorsum is flat and the dorsolateral margin is fairly sharply rounded. The inner flanks are broadly rounded and the outer flanks converge toward the venter. The venter is set off by a weak, longitudinal furrow and the ventrolateral shoulder is fairly abruptly rounded; the venter is narrow and flat.

Weak swellings occur on the dorsal onehalf of the flanks with a distance of 13.5 mm between the two most adoral swellings; the rib index is approximately 2.5. The venter is covered with swollen ribs that show a slight forward projection. The ribs are spaced at distances of 4 mm so that the rib index is approximately 6.5.

AMNH 47412 is the adapical part of a body chamber 48.4 mm long (fig. 28L–P). The whorl heights are 14.1 mm and 15.7 mm at the adapical and adoral ends, respectively. The whorl section at the adoral end is pyriform with an intercostal ratio of whorl width to height of 0.73. The angle of taper is 2.2°. The dorsum is nearly flat to very broadly rounded and the dorsolateral margin is fairly abruptly rounded. The flanks are broadly rounded with maximum width at one­third whorl height. The outer flanks converge to the venter. The venter is flat and narrow and is bordered by a ventrolateral furrow producing a keel. The ventrolateral shoulder is abruptly rounded.

There are very faint, convex folds on the dorsum. Broad, crescentic ribs cover the dorsal one­half of the flanks. On the left side, these ribs are of variable strength and spacing with a rib index of 4, whereas on the right side, these ribs are more nodate with a rib index of 2. Ribs slant strongly forward to the ventrolateral margin. The venter is covered with fairly coarse ribs, which show a weak forward projection, producing a serrat­ ed appearance; the rib index is 8.

AMNH 47416 is a fragment of a body chamber 45.6 mm long with whorl heights of 13.9 mm and 17.5 mm at the adapical and adoral ends, respectively (fig. 28Q–T). The ratio of whorl width to height at the adoral end is 0.69. Broad, weak crescentic swellings cover the dorsal one­half of the flanks with a rib index of approximately 3. The left side shows a dent near the adapical end, which is probably the result of an injury. The venter is mostly eroded away but shows three swollen transverse ribs on the adoral end. The ribs are spaced at distances of 2 mm so that the rib index is approximately 10.

MAPS A 2058a4 is a strongly ribbed fragment of a body chamber 59.7 mm long with whorl heights of 15.6 mm and 16.4 mm at the adapical and adoral ends, respectively (fig. 29A–E). The intercostal ratio of whorl width to height at the adoral end is 0.70. The angle of taper is 1.2°. There is a shallow, longitudinal groove on either side of a fastigiate to tabulate venter. The dorsum is covered with low folds that show a relatively strong adoral projection. There are broad, asymmetrically crescentic ribs on the dorsal one­half of the flanks with a rib index of 3. The venter is notched with swollen ribs showing a slight adoral projection; the rib index is 5.5.

AMNH 47410 is a body chamber fragment with some iridescent shell on the adapical end; the angle of taper is 3.8° (fig. 29F–I). It is 46.5 mm long with whorl heights of 13.4 mm and 15.7 mm at the adapical and adoral ends, respectively. The intercostal ratio of whorl width to height at the adoral end is 0.73. The whorl section is pyriform with a broadly rounded to flat dorsum and fairly sharply rounded dorsolateral margin. The inner flanks are broadly rounded and the outer flanks converge to the venter. The venter is bordered by a faint longitudinal groove. The ventrolateral shoulder is fairly steeply round­ ed and the venter is narrow and tabulate. Swollen, concave ribs cover the inner onehalf of the flanks. The distance between rib crests is approximately 8 mm near the adoral end so that the rib index is approximately 3. Ribs weaken and break down into riblets on the outer one­third of the flanks. They slant strongly forward at an angle of approximately 20°. The ribs strengthen on the venter and are spaced every 2 mm near the adoral end, so that the rib index is approximately 7.

AMNH 47511 is a coarsely ornamented fragment of the adapical part of a body chamber 38.8 mm long with whorl heights of 12.5 mm and 15.0 mm at the adapical and adoral ends, respectively (fig. 29J–M). The intercostal ratio of whorl width to height at the adoral end is 0.72. The angle of taper is 4.2°. There are low folds on the dorsum. The inner two­thirds of the flanks bear strong, crescentic ribs spaced at distances of approximately 10 mm at the adoral end, so that the rib index is 2.5. The venter is narrow and tabulate and ornamented with strong, transverse ribs that show a slight adoral projection, producing a serrated appearance; the rib index is 5.

AMNH 47415 is a small specimen of a body chamber 35.6 mm long, with relatively coarse ornament (fig. 29N–R). The whorl heights are 12.3 mm and 14.1 mm at the adapical and adoral ends, respectively. The intercostal ratio of whorl width to height at the adoral end is 0.75. The angle of taper is 3.6°. The inner one­half of the flanks are covered with four slightly crescentic nodelike swellings with the interspaces between them as broad as the swellings themselves. The distance between node crests is 9 mm, so that the rib index is approximately 2.5. The ribs slant strongly forward on the outer one­half of the flanks at an angle of approximately 20°. The narrow tabulate venter is covered with swollen, convex ribs spaced at distances of 2.5–3.0 mm, yielding a rib index of 6.

AMNH 47413 is a small piece of the adoral part of a phragmocone and the adapical part of a body chamber of a specimen 35.9 mm long (fig. 29V–X). The whorl heights at the adapical and adoral ends are 9.2 mm and 11.9 mm, respectively. The ratio of whorl width to height at the adoral end is 0.75. The angle of taper is 5.2°. The inner one­half of the flanks are covered with broad, crescentic ribs with the interspaces between them as broad as the ribs themselves. The distance between rib crests at the adoral end of the specimen is 6 mm; the rib index is approximately 3. The narrow tabulate venter is smooth.

AMNH 47504 is a fragment of a body chamber 35.3 mm long with whorl heights of 9.7 mm and 11.0 mm at the adapical and adoral ends, respectively (fig. 29Y–b). The ratio of whorl width to height at the adoral end is 0.79. The angle of taper is 4.0°. The dorsal one­half of the flanks bear nodelike swellings with a rib index of approximately 2. The ribs weaken and slant strongly forward on the outer one­half of the flanks. They are transverse on the venter, with a rib index of 6.

AMNH 47270 (not illustrated) is a body chamber fragment 55.8 mm long with a whorl height of 22.6 mm at the adoral end. The whorl section is compressed ovoid at the adoral end with a ratio of whorl width to height of 0.75. The dorsum is broad and nearly flat and the dorsolateral shoulder is fairly abruptly rounded. The inner flanks are broadly rounded and nearly parallel and the outer flanks converge toward the venter. The venter is narrow and tabulate and the ventrolateral shoulder is abruptly rounded. There is a shallow longitudinal groove that borders the venter. The dorsum is covered with low, convex folds. The venter is nearly smooth and the dorsal one­half of the flanks bear widely spaced nodelike swellings with a rib index of approximately 2.5.

AMNH 47444 is one of the smallest fragments in our collection, a piece of phragmocone, 13.6 mm in length, with whorl heights of 9.9 mm and 10.6 mm at the adapical and adoral ends, respectively (not illustrated). The ratio of whorl width to height at the adoral end is 0.74. There are two nodelike swellings on the inner flanks with a rib index of 2. The ribs are very weak on the tabulate venter with a rib index of 4.5 based on a distance of 3 mm between the two most adoral ribs.

MAPS A 2058a6 (not illustrated) is a completely septate fragment 63.0 mm long with whorl heights of 16.0 mm and 18.7 mm at the adapical and adoral ends, respectively. The whorl section at the adoral end is compressed ovoid with a ratio of whorl width to height of 0.75. The dorsum is very broadly rounded and the dorsolateral margin is well rounded. The flanks are broadly rounded and converge toward the venter with maximum width at midwhorl height. The venter is bordered by a shallow, longitudinal depression and the ventrolateral shoulder is fairly sharply rounded; the venter is broadly rounded to flat. The inner one­half of the flanks are smooth except for weak, nodelike swellings with a rib index of approximately 2. Broad, transverse ribs cover the venter with a rib index of 7. Parts of the last and next to last suture are illustrated in figure 30B. The sutures are worn but show a bifid L/U, a broad, bifid U, and a narrow I.

AMNH 47159 is a fragment of the adapical end of a body chamber 43.4 mm long with whorl heights of 11.2 mm and 13.4 mm at the adapical and adoral ends, respectively (fig. 33U–Y). The ratio of whorl width to height at the adoral end is 0.74. The venter is narrow and nearly flat and is bordered by a longitudinal furrow. There are weak crescentic swellings on the dorsal one­half of the flanks with a rib index of approximately 3. The venter is ornamented with weak, transverse ribs with a rib index of approximately 8.

DISCUSSION: This species is characterized by a narrow, tabulate venter ornamented with ribs producing a serrated appearance, and broad, asymmetrically crescentic ribs on the dorsal one­half of the flanks. The full range of variation of this species has been recently discussed by Klinger and Kennedy (1993),

section at adoral end. L–P. AMNH 47412. L, Right lateral; M, ventral; N, dorsal; O, left lateral; P, whorl cross section at adoral end. Q–T. AMNH 47416. Q, Right lateral; R, ventral; S, dorsal; T, left lateral. U–Y. AMNH 47420. U, Right lateral; V, ventral; W, dorsal; X, left lateral; Y, whorl crosssection at adoral end. All figures X1.

Cobban and Kennedy (1995), and Kennedy and Cobban (2000).

OCCURRENCE: This species occurs in New Jersey in the upper part of the New Egypt Formation and as reworked material at the base of the Hornerstown Formation, near Eatontown, northeastern Monmouth County; at the top of the New Egypt Formation in the Crosswicks Creek Basin, southwestern Monmouth County (Landman et al., in prep. b); and in the New Egypt Formation at the Inversand Pit, near Sewell, Gloucester County ( Kennedy and Cobban, 1996). It also occurs at the top of the Tinton Formation and as reworked material at the base of the Hornerstown Formation near Freehold, central Monmouth County (Landman et al., in prep. a). Kennedy and Cobban (1996: fig. 3.1–3.3, 3.7–3.12) recorded three specimens of this species (USNM 12691a–c), ex J.B. Marcou collection, labeled ‘‘New Jersey’’, which they inferred to be from the base of the Hornerstown Formation. This species is reported elsewhere on the Gulf and Atlantic Coastal Plains from the top of the Corsicana Formation and as reworked material at the base of the Kincaid Formation, Falls County, Texas ( Kennedy et al., 2001); the Owl Creek Formation, Mississippi, Missouri, and Tennessee ( Kennedy and Cobban, 2000); the Prairie Bluff Chalk, Alabama and Mississippi ( Cobban and Kennedy, 1995); and the Severn Formation, Maryland ( Kennedy et al., 1997; Landman et al., 2004). It is also reported from southeast France, Austria, the Netherlands, Zululand ( South Africa), Mozambique, Madagascar, southern India, Western Australia, Chile, Argentina, and California. It ranges from the upper lower to the upper upper Maastrichtian (Klinger et al., 2001).

Eubaculites latecarinatus ( Brunnschweiler, 1966)

Figures 30C, D , 31 , 32

Eubaculites otacodensis (Stoliczka) . Spath, 1940: 49 (pars), text­fig. 1c.

Giralites latecarinatus Brunnschweiler, 1966: 33 , pl. 3, figs. 13, 14; pl. 4, figs. 1–5; text­figs. 17, 18.

Giralites quadrisulcatus Brunnschweiler, 1966: 35 , pl. 4, figs. 11–14; text­fig. 20.

Eubaculites ambindensis Collignon, 1971: 18 , pl. 646, fig. 2393.

Eubaculites latecarinatus (Brunnschweiler) . Klinger, 1976: 91, pl. 40, fig. 1; pl. 41, fig. 3; pl. 42, figs. 2, 6; pl. 43, figs. 3, 4; text­figs. 11d, e.

Eubaculites latecarinatus (Brunnschweiler) . Klinger and Kennedy in Klinger et al., 1980: 296, figs. 2a–c, 3a–d, 4a–c, 5b.

Eubaculites latecarinatus ( Brunnschweiler, 1966) . Henderson et al., 1992: 159, figs. 22L–N, 23N–P.

Eubaculites latecarinatus ( Brunnschweiler, 1966) . Klinger and Kennedy, 1993: 238, figs. 26A, 39–41, 42B, C, 43–49, 50A, 52A.

Eubaculites latecarinatus ( Brunnschweiler, 1966) . Kennedy et al., 1997: 20, figs. 15A–D, K, L, 16G, H, 19.

Eubaculites latecarinatus ( Brunnschweiler, 1966) . Klinger and Kennedy, 2001: 234.

Eubaculites latecarinatus ( Brunnschweiler, 1966) . Klinger et al., 2001: 287, pl. 10, figs. 4–9; textfig. 6.

TYPE: The holotype, by original designation, is the original of Brunnschweiler (1966: pl. 4, figs. 2–4) from the Maastrichtian of western Australia.

MATERIAL: There are 94 specimens, 4 of which are float, from the upper part of the New Egypt Formation and basal part of the Hornerstown Formation on Parkers Creek , AMNH loc. 3345, near Eatontown, northeastern Monmouth County, New Jersey. All of the specimens are internal molds of fragments less than 75 mm in length ; some of

adoral end. F–I. AMNH 47410. F, Right lateral; G, dorsal; H, ventral; I, whorl cross section at adoral end. J–M. AMNH 47511. J, Right lateral; K, dorsal; L, ventral; M, left lateral. N– R. AMNH 47415. N, Right lateral; O, dorsal; P, ventral; Q, left lateral; R, whorl cross section at adoral end. S–U. MAPS A 2058a5. S, Dorsal; T, ventral; U, left lateral. V –X. AMNH 47413. V, Right lateral; W, dorsal; X, ventral. Y—Z, a, b. AMNH 47504. Y, Right lateral; Z, dorsal; a, ventral; b, whorl cross section at adoral end. c–f. AMNH 47421. c, Right lateral; d, dorsal; e, ventral; f, whorl cross section at adoral end. g–j. AMNH 47424. g, Right lateral; h, dorsal; i, ventral; j, whorl cross section at adoral end. k– m. AMNH 47423. k, Right lateral; l, dorsal; m, ventral. All figures are X1.

them preserve the original shell material of the septa. Most of the specimens are fragments of body chambers—there are 14 completely septate pieces (15% of the total).

DESCRIPTION: The collection consists of ro­ bust and slender forms that are distinguished, in part, by their angle of taper, although this measurement is very dependent on ontogenetic stage (table 7). These two forms may represent dimorphs, but without better infor­

TABLE 6 Measurements of Eubaculites carinatus ( Morton, 1834) a

mation on the ontogenetic stage of the specimens, this conclusion is difficult to prove. We provide descriptions of 15 specimens to cover the range of variation in our collection.

AMNH 47273 is a fragment of the adoral part of a phragmocone and the adapical part of a body chamber of a specimen 56.4 mm long (fig. 31A–E). The whorl heights at the adapical and adoral ends are 15.7 mm and 18.8 mm, respectively. The whorl section at the adoral end is compressed ovoid with a ratio of whorl width to height of 0.66. The angle of taper is 2.8°. The dorsum is covered with weak, broad folds with a strong adoral projection. Ribs are asymmetrically crescentic on the inner one­half of the flanks with a rib index of 7, and slant strongly forward on the outer one­half of the flanks. Ribs are weak and swollen on the venter with a rib index of 6.

AMNH 47414 is a small piece of a body chamber 38.0 mm long with whorl heights of 15.9 mm and 17.3 mm at the adapical and adoral ends, respectively (fig. 31F–I). The flanks are smooth and the right side is partly covered by a bryozoan colony. The venter is narrow and tabulate without any trace of ribs.

AMNH 47411 is a body chamber fragment 43.4 mm long with whorl heights of 13.4 mm and 15.3 mm at the adapical and adoral ends, respectively (fig. 31J–N). The intercostal whorl section at the adoral end is pyriform with a ratio of whorl width to height of 0.76. The angle of taper is 3.4°. The dorsum is smooth. The inner one­half of the flanks bear crescentic, swollen ribs; the two most adoral ribs on the right side are 6.5 mm apart; the rib index is 4. The ribs slant sharply forward on the outer one­half of the flanks at an angle of approximately 20°. The ribs are faint on the narrow, tabulate venter, with an index of 7.

AMNH 47417 is a fragment of a body chamber 45.7 mm long with whorl heights of 13.7 mm and 14.8 mm at the adapical and adoral ends, respectively (fig. 31O–S). The ratio of whorl width to height at the adoral end is 0.74. The venter is narrow and flat and set off by a narrow ventrolateral furrow. Ribs are very weak on the dorsum and show a strong adoral projection. The inner one­half of the flanks bear weak, crescentic ribs with very faint riblets or striae between them. The distance between consecutive ribs is approximately 9 mm, yielding a rib index of 2.5. Ribs slant strongly forward on the outer onehalf of the flanks. The venter is covered with barely perceptible ribs, although this may be due in part to poor preservation. The spacing between consecutive ribs is 3.5 mm, yielding a rib index of 5.

AMNH 47422 is a fragment of a body chamber 39.6 mm long with whorl heights of 15.1 mm and 16.4 mm at the adapical and adoral ends, respectively (fig. 31T–W). The ratio of whorl width to height at the adoral end is 0.74. The outer flanks are nearly smooth with very faint, low crescentic ribs; the rib index is 3. The venter, which is set off by a deep ventrolateral groove, is mostly covered by matrix.

AMNH 47425 is a fragment of the adoral part of a phragmocone and the adapical part of the body chamber (fig. 31X–Z, a,b). It is 36.0 mm long with some iridescent shell material on the dorsum. The whorl heights at the adapical and adoral ends are 13.5 mm and 14.8 mm, respectively. The ratio of whorl width to height at the adoral end is 0.71. The angle of taper is 2.4°. The dorsum, especially on the adapical end, is covered with faint, low, strongly convex ribs. The two most adapical ribs are approximately 3 mm apart. The inner flanks are smooth with only a slight trace of crescentic ribs on the dorsolateral margin on the right side near the adapical end. The ribs strengthen slightly and slant steeply forward on the outer flanks. The venter is covered with swollen transverse ribs with a rib index of 6.

AMNH 47426 is a fragment of a body chamber 36.4 mm long with whorl heights of 12.0 mm and 13.2 mm at the adapical and adoral ends, respectively (fig. 31c–g). The ratio of whorl width to height at the adoral end is 0.71. The inner flanks are nearly smooth with very faint crescentic ribs with a rib index of approximately 4. The narrow tabulate venter is covered with transverse to slightly convex ribs with a rib index of 8.

AMNH 47408 is 69.3 mm long and consists of the adoral part of a phragmocone and the adapical part of the body chamber (fig. 32A–E). The whorl heights at the adapical and adoral ends are 10.9 mm and 14.8 mm, respectively. The ratio of whorl width to height at the adoral end is 0.70. The angle of taper is 4.0°. The venter is set off by a faint ventrolateral furrow. Ribs cross the dorsum with a slight adoral projection. They swing backward on the dorsolateral margin and are strongly concave on the inner one­half of the flanks. They are very weak and closely spaced on most of the specimen until a whorl height of 14.4 mm, where they become nodelike and more widely spaced. The distance between the two most adoral nodes is 11 mm, yielding a rib index of 2. Ribs slant steeply forward at an angle of approximately 20° on the outer one­half of the flanks. The venter is covered with faint transverse ribs spaced at distances of 1–2 mm so that the rib index is approximately 10.

MAPS A 2053c5 is the adapical part of a body chamber 47.2 mm long with whorl heights of 11.2 mm and 13.8 mm at the adapical and adoral ends, respectively (fig. 32F– J). The whorl section at the adoral end is compressed ovoid with a ratio of whorl width

at adoral end. F–I. AMNH 47414. F, Right lateral; G, dorsal; H, ventral; I, whorl cross section at adoral end. J–N. AMNH 47411. J, Right lateral; K, dorsal; L, ventral; M, left lateral; N, whorl cross section at adoral end. O–S. AMNH 47417. O, Right lateral; P, dorsal; Q, ventral; R, left lateral; S, whorl cross section at adoral end. T–W. AMNH 47422. T, Right lateral; U, dorsal; V, ventral; W, whorl cross section at adoral end. X—Z, a, b. AMNH 47425. X, Right lateral; Y, dorsal; Z, ventral; a, left lateral; b, whorl cross section at adoral end. c–g. AMNH 47426. c, Right lateral; d, dorsal, e, ventral; f, left lateral; g, whorl cross section at adoral end. h–k. AMNH 47406. h, Right lateral; i, dorsal; j, ventral; k, left lateral. All figures are X1.

TABLE 7 Measurements of Eubaculites latecarinatus ( Brunnschweiler, 1966) a

to height of 0.72. The angle of taper is 3.6°. The inner flanks are ornamented with very faint, asymmetrically crescentic ribs with a rib index of 3. The venter bears faint transverse ribs with a rib index of 5.

AMNH 47407 is a fragment consisting of the adoral part of a phragmocone and adapical part of the body chamber (fig. 32O–S). It is 38.0 mm long with whorl heights of 11.6 mm and 12.2 mm at the adapical and adoral ends, respectively. The ratio of whorl width to height at the adoral end is 0.79. The angle of taper is 3.2°. There are very faint crescentic swellings on the inner flanks spaced at distances of approximately 7.0 mm, yielding a rib index of 3. The narrow tabulate venter is covered with conspicuous swollen ribs that arch slightly forward. They are evenly spaced at distances of approximately 2 mm, yielding a rib index of 7.

AMNH 47419 is a fragment of a body chamber with some iridescent shell on the dorsum and last septum (fig. 32T–X). It is 43.2 mm long with whorl heights of 11.7 mm and 14.9 mm at the adapical and adoral ends, respectively. The angle of taper is 3.4°. Ribs cross the dorsum with a moderately strong adoral projection. The inner one­half of the flanks are nearly smooth with very weak, broad, crescentic ribs with a rib index of approximately 6. The venter is nearly smooth with very faint ribs.

MAPS A 2053c4 (not illustrated) is a completely septate fragment 40.7 mm long with whorl heights of 16.0 mm and 18.0 mm at the adapical and adoral ends, respectively. The whorl section at the adoral end is compressed ovoid with a ratio of whorl width to height of 0.72. The inner flanks are smooth although the specimen is not well preserved. The venter is flat and relatively broad and is covered with faint, transverse ribs with a rib index of approximately 8.

MAPS A 2053c3 (not illustrated) is a fragment of the adapical part of a body chamber 48.2 mm long with whorl heights of 11.4 mm and 16.1 mm at the adapical and adoral ends, respectively. The whorl section at the adoral end is compressed ovoid with a ratio of whorl width to height of 0.71. The dorsum is flat and the dorsolateral shoulder is fairly sharply rounded. The inner flanks are broadly rounded with maximum width at midwhorl height. The outer flanks converge steeply to the venter, which is bordered by a shallow longitudinal groove. The ventrolateral shoulder is fairly sharply rounded and the venter is flat. The dorsum bears faint con­ vex folds, the flanks are smooth, and the venter is covered with broad, transverse ribs with a rib index of 6.

AMNH 47432 (not illustrated) is a fragment of a body chamber 36.3 mm long with whorl heights of 13.9 mm and 14.6 mm at the adapical and adoral ends, respectively. The ratio of whorl width to height at the adoral end is 0.74. There are broad crescentic ribs on the dorsal one­half of the flanks with a rib index of 3. The tabulate venter is covered with swollen, transverse ribs with a rib index of 6.

AMNH 47500 (not illustrated) is a fragment of a body chamber 33.0 mm long with whorl heights of 10.2 mm and 12.1 mm at the adapical and adoral ends, respectively. The ratio of whorl width to height at the adoral end is 0.73. The dorsum is covered with weak adorally projected folds. A low ridge occurs along the midline of the dorsum. Weak, asymmetrically crescentic ribs cover the dorsal one­half of the flanks. Smaller riblets appear between two of these ribs; the rib index is 4. The venter is narrow and broadly rounded and is covered with faint, transverse ribs with a rib index of approximately 5.

Parts of the sutures of two specimens (AMNH 47493 and 47501) are illustrated in Figure 30C, D and show a bifid E/L, a narrow, bifid L, a broad, bifid L/U, a bifid U, and a narrow I.

DISCUSSION: This species is characterized by weak to no ornament on the flanks, and a narrow, tabulate venter covered with ribs, producing a serrated appearance. Klinger and Kennedy (1993, 2001) described this species from Zululand and Natal, South Africa, where specimens attain a much larger size than those from New Jersey. These authors also noted the presence of smooth specimens of Eubaculites carinatus that are identical to E. latecarinatus , but argued that populations of these two species are sufficiently distinct to separate them. The two species are not equally abundant in Zululand, with E. latecarinatus more common than E. carinatus . This disparity is also reflected in our sample; E. latecarinatus is 20% more abundant than E. carinatus . However, all of our specimens are internal molds and the absence of ornamentation, interpreted as indicating E. latecarinatus , may be a reflection of poor pres­ ervation, implying that the abundance of E. latecarinatus may be overestimated. In addition, our specimens are fragmentary, making it difficult to distinguish between ontogenetic and intraspecific variation (see Tsujino et al., 2003).

OCCURRENCE: This species occurs in New Jersey in the upper part of the New Egypt Formation and as reworked material at the base of the Hornerstown Formation, near Eatontown, northeastern Monmouth County; in the top of the New Egypt Formation in the Crosswicks Creek Basin, southwestern Monmouth County (Landman et al., in prep. b); and in the top of the Tinton Formation and as reworked material at the base of the Hornerstown Formation near Freehold, central Monmouth County (Landman et al., in prep. a). This species is also known from the Severn Formation, Prince Georges County, Maryland ( Kennedy et al., 1997), and Kent County, Maryland ( Landman et al., 2004). Klinger and Kennedy (2001) reported this species from the Maastrichtian of Zululand, South Africa, the offshore Alphard Group, south India, Madagascar, and Western Australia.

Figures

Fig. 27. Eubaculites carinatus (Morton, 1834). Uppermost New Egypt Formation and basal Hornerstown Formation, AMNH loc. 3345, northwest of Eatontown, Monmouth County, New Jersey. A–E.

Fig. 28. Eubaculites carinatus (Morton, 1834). Uppermost New Egypt Formation and basal Hornerstown Formation, AMNH loc. 3345, northwest of Eatontown, Monmouth County, New Jersey. A– C. AMNH 47508. A, Left lateral; B, ventral; C, dorsal. D–G. AMNH 47272. D, Left lateral; E, ventral; F, dorsal; G, right lateral. H–K. AMNH 47409. H, Right lateral; I, ventral; J, dorsal; K, whorl cross

Fig. 29. Eubaculites carinatus (Morton, 1834). Uppermost New Egypt Formation and basal Hornerstown Formation, AMNH loc. 3345, northwest of Eatontown, Monmouth County, New Jersey. A– E. MAPS A2058a4. A, Right lateral; B, dorsal; C, ventral; D, left lateral; E, whorl cross section at

Fig. 30. A, B. Eubaculites carinatus (Morton, 1834). Uppermost New Egypt Formation and basal Hornerstown Formation, Parkers Creek, northwest of Eatontown, Monmouth County, New Jersey. A. AMNH 47253, last suture at a whorl height of approximately 12.9 mm. B. MAPS A2058a6, parts of the last and next to last suture at a whorl height of approximately 19.1 mm. C, D. Eubaculites latecarinatus (Brunnschweiler, 1966), same locality as A, B. C. AMNH 47493, last suture and parts of third and fourth to last sutures, at a whorl height of approximately 11.4 mm. D. AMNH 47501, at a whorl height of approximately 12.2 mm.

Fig. 33. A–T. Eubaculites sp. Upper New Egypt Formation, 1.5–2 m below the base of the Hornerstown Formation, AMNH loc. 3346, northwest of Eatontown, Monmouth County, New Jersey. A– E. MAPS A2053c1. A, Right lateral; B, dorsal; C, ventral; D, left lateral; E, whorl cross section at adapical end. F–J. AMNH 47160. F, Right lateral; G, dorsal; H, ventral; I, left lateral; J, whorl cross

Fig. 31. Eubaculites latecarinatus (Brunnschweiler, 1966). Uppermost New Egypt Formation and basal Hornerstown Formation, AMNH loc. 3345, northwest of Eatontown, Monmouth County, New Jersey. A–E. AMNH 47273. A, Right lateral; B, dorsal; C, ventral; D, left lateral; E, whorl cross section

Fig. 32. Eubaculites latecarinatus (Brunnschweiler, 1966). Uppermost New Egypt Formation and basal Hornerstown Formation, AMNH loc. 3345, northwest of Eatontown, Monmouth County, New Jersey. A–E. AMNH 47408. A, Right lateral; B, dorsal; C, ventral; D, left lateral; E, whorl cross section at adoral end. F–J. MAPS A2053c5. F, Right lateral; G, dorsal; H, ventral; I, left lateral; J, whorl cross section at adoral end. K–N. AMNH 47405. K, Right lateral; L, dorsal; M, ventral; N, left lateral. O– S. AMNH 47407. O, Right lateral; P, dorsal; Q, ventral; R, left lateral; S, whorl cross section at adoral end. T–X. AMNH 47419. T, Right lateral; U, dorsal; V, ventral; W, left lateral; X, whorl cross section at adoral end. Y. AMNH 47404, partly in nodule. Z. AMNH 50544, partly in nodule. All figures