Discoscaphites gulosus ( Morton, 1834 )

LANDMAN, NEIL H., JOHNSON, RALPH O., GARB, MATTHEW P., EDWARDS, LUCY E. & KYTE, FRANK T., 2007, CEPHALOPODS FROM THE CRETACEOUS / TERTIARY BOUNDARY INTERVAL ON THE ATLANTIC COASTAL PLAIN, WITH A DESCRIPTION OF THE HIGHEST AMMONITE ZONES IN NORTH AMERICA. PART III. MANASQUAN RIVER BASIN, MONMOUTH COUNTY, NEW JERSEY, Bulletin of the American Museum of Natural History 303 (1), pp. 1-122 : 1-122

Discoscaphites gulosus ( Morton, 1834) spaced rows of small, round tubercles. The figure 51 most prominent tubercle on the specimen is near the umbilical margin.

Ammonites conradi var. petechialis Morton, 1834:

39, 40, pl. 16, fig. 1. DISCUSSION : Macroconchs of Discosca- Ammonites conradi var. gulosus Morton, 1834: 39 , phites gulosus from the D. iris Zone on the 40, pl. 16, fig. 2 . Altantic Coastal Plain display five tubercle Ammonites conradi var. navicularis Morton, 1834 : rows ( fig. 51 ; Kennedy et al., 2000: fig. 9G–I ). 40, pl. 19, fig. 4 . [This also applies to an incomplete specimen Discoscaphites conradi gulosus ( Morton, 1834) . of this species in which the dimorph is Jeletzky and Waage, 1978: 1129, pl. 2, figs. 1 –

indeterminate ( Landman et al., 2004b: fig. 19; pl. 3, figs. 1–15 ; text-fig. 1B, C, E, F.

39Y, Z, a, b). Similarly, the specimen of Discoscaphites gulosus ( Morton, 1834) . Landman and Waage, 1993: 212, figs. 156, 157, 159, 160, Discoscaphites sp. cf. gulosus reported from 167–180 (with full synonymy). the D. iris Zone of Texas displays five tubercle Discoscaphites gulosus ( Morton, 1834) . Cobban rows ( Kennedy et al., 2001: fig. 4f )]. In and Kennedy, 1995: 29, figs. 10.4, 10.5 , 19.20 – contrast, macroconchs of D. gulosus from 19.24, 20.8–20.12, 20.14–20.17, 21.18–21.21. the stratigraphically lower D. conradi Zone on Discoscaphites gulosus ( Morton, 1834) . Kennedy et the Gulf and Atlantic Coastal Plains exhibit al., 1997: figs. 20K–O , 21D, E . either five or six tubercle rows (e.g., Jeletzky Discoscaphites gulosus ( Morton, 1834) . Landman

and Waage, 1978: pl. 2, figs. 8–11 , 16–19 ; pl. et al., 2004a: 37, figs. 12C–J, 16.

3, figs. 1–3 ; Cobban and Kennedy, 1995: figs. Discoscaphites gulosus ( Morton, 1834) . Landman et al., 2004b: 92, figs. 39Y, Z, a, b, 41E. 19.20–19.24, 20.1, 20.2, 20.8–20.12 ; Kennedy et al., 1997: fig. 20K–M ; Landman et al., TYPE: The holotype is ANSP 51552 from 2004a: 12C,D,H–J, 16). The D. conradi Zone the Prairie Bluff Chalk at Prairie Bluff, is approximately equivalent to the Hoplosca- Alabama. phites nicolletii and Jeletzkytes nebrascensis MATERIAL: MAPS A2025c1, Pinna Lay- Zones of the Western Interior (Landman et er, Manasquan River Basin, Monmouth al., 2004a). Macroconchs from these two County, New Jersey. zones also display either five or six rows of DESCRIPTION: MAPS A2025c1 is part of tubercles ( Landman and Waage, 1993: figs. the shaft of a body chamber of a large 167A–C, 168A–C, 169A–F, 170A–C, 171A– macroconch ( fig. 51 ). The midflanks are F, 172A–E). Thus, these data suggest a tembroadly rounded and slightly convergent poral reduction in the number of tubercle and the outer flanks are nearly flat and more rows, with younger forms of D. gulosus steeply convergent. There are five equally having one fewer row.

OCCURRENCE: Pinna Layer, Tinton Formation, Manasquan River Basin , New Jersey. Elsewhere in New Jersey, this species occurs at the top of the New Egypt Formation and as reworked material at the base of the Hornerstown Formation, near Eatontown, Monmouth County ( Landman et al., 2004b), and in the Navesink Formation (New Egypt Formation according to our usage) at the Inversand Marl Pit, Gloucester County (Kennedy et al., 2000). This species also occurs in several localities on the Gulf and Atlantic Coastal Plains including the Severn Formation, Prince Georges County, Maryland ( Kennedy et al., 1997); the Peedee Formation, Brunswick County, North Carolina ( Landman et al., 2004a); and the Prairie Bluff Chalk, Alabama ( Cobban and Kennedy, 1995). In the Western Interior, D. gulosus occurs in both the Hoploscaphites nicolletii and Jelezkytes nebrascensis Zones of the Fox Hills Formation, South Dakota ( Landman and Waage, 1993).

Figures

Fig. 51. Discoscaphites gulosus (Morton, 1834), macroconch, MAPS A2025c1, Pinna Layer, top of the Tinton Formation, Manasquan River Basin, Monmouth County, New Jersey. A. Lateral view of part of the shaft; B. ventral view. Both figures X1.

Fig. 1. Map of parts of New Jersey showing localities mentioned in the text. The Manasquan River Basin is indicated by an arrow.

Fig. 2. Detailed locality map of the Manasquan River Basin, central Monmouth County, New Jersey, showing the Tinton Formation and overlying Hornerstown Formation. Numbers correspond to AMNH localities described in the text.

Fig. 9. Gastropods from the top of the Tinton Formation, Manasquan River Basin, Monmouth County, New Jersey. A, B. Turritella bilira Stephenson, 1941, MAPS A2838e1. C, D. Deussenia sp., MAPS A2821b1. E–G. Bellifusus sp. E. MAPS A2889e1. F, G. MAPS A2889e2. H, I. Gyrodes spillmani Gabb, 1861. H. MAPS A2873c1. I. MAPS A2873c2. J, K. Gyrodes supraplicatus (Conrad, 1858). J. MAPS A2872f1. K. MAPS A2872f2. L. Pterocerella sp., MAPS A2877d1. M, N. Arrhoges sp. M. MAPS A2906a1. N. MAPS A2906a2. O–Q. Anchura substriata? Wade, 1926. O, P. MAPS A2905b1. Q. MAPS A2905b2. All figures X1.

Fig. 4. Stratigraphic section at AMNH loc. 3372, Manasquan River Basin, Monmouth County, New Jersey, showing the upper part of the Tinton Formation, including the Pinna Layer, and the overlying Hornerstown Formation, including the Burrowed Unit. The reworked nodules (arrows) in the basal Hornerstown Formation contain Cretaceous fossils. The position of the iridium spike at the base of the Pinna Layer is indicated by an asterisk.

Fig. 10. Gastropods from the top of the Tinton Formation, Manasquan River Basin, Monmouth County, New Jersey. A. Xenophora leprosa (Morton, 1834), MAPS A2801j1. B–E. Epitonium? sp. B, C. MAPS A2874f1. D. MAPS A2874f3. E. MAPS A2874f2. F–H. Pyropsis trochiformis (Toumey, 1854), MAPS A2862b1. I–L. Unidentified gastropods. I, J. MAPS A2950a1. K, L. MAPS A2951a1. All figures X1.

Fig. 20. Scaphite with hollow inner whorls, AMNH 50777, from a nodule at the base of the Hornerstown Formation, AMNH loc. 3372, Monmouth County, New Jersey. A. Overview. B. Close-up. C. Close-up of septal neck (arrow). D. Close-up of primary constriction (arrow) marking the point of hatching.

Fig. 21. Concentration of iridium (pg/g) at AMNH locs. 3372 (.) and 3391 (&), Manasquan River Basin, central Monmouth County, New Jersey. The scale (cm) is drawn such that 0 cm marks the boundary between the Tinton and Hornerstown formations. The highest concentration of iridium occurs at the base of the Pinna Layer, but the highest non-reworked ammonites occur approximately 20 cm higher up, at the top of the Pinna Layer.

Fig. 8. Gastropods from the top of the Tinton Formation, Manasquan River Basin, Monmouth County, New Jersey. A–C. Euspira sp. A, B. MAPS A2809e1. C. MAPS A2809e2. D, E. Pyropsis sp. D. MAPS A2800k1. E. MAPS A2800k2. F, G. Calliomphalus sp., MAPS A2897b1. H–J. Napulus sp. H, I. MAPS A2859d1. J. MAPS A2859d2. K–O. Cylichna sp. K, L. MAPS A2908a1. M. MAPS A2908a2. N. MAPS A2908a3. O. MAPS A2908a4. P–S. Ellipsoscapha sp. P, Q. MAPS A2833f1. R, S. MAPS A2833f2. T, U. Pseudomalaxis sp. T. MAPS A2907a1. U. MAPS A2907a2. V–X. Anchura sp. V, W. MAPS A2909a1. X. MAPS A2909a2. Y, Z, a. Belliscala? sp. Y, Z. MAPS A2888c1. a. MAPS A2888c2. b, c. Bullopsis demersus Sohl, 1964, MAPS A2949a1. d, e. Latiaxis sp., MAPS A2948a1. f–h. Margaritella pumila Stephenson, 1941. f, g. MAPS A2911d2. h. MAPS A2911d1. All figures X1.

Fig. 16. Echinoids from the top of the Tinton Formation, Manasquan River Basin, Monmouth County, New Jersey. A, C, D, G, H. Hemiaster dalli Clark, 1891. A. Association with a fragment of Discoscaphites iris (Conrad, 1858), MAPS A3609a3. C, D. MAPS A3609a1. G, H. MAPS A3609a2. B, I– K. Cardiaster marylandica Clark, 1916. B. Cluster of juveniles, MAPS A3601g3. I, J. MAPS A3601g1. K. Association with Eubaculites latecarinatus (Brunnschweiler, 1966), MAPS A3601g2. E, F. Hemiaster delawarensis Clark, 1916, MAPS A3605f1. All figures X1.