Scaphites (Scaphites) hippocrepis ( DeKay, 1828 ) III Cobban, 1969

Ifrim, Christina & Stinnesbeck, Wolfgang, 2021, Ammonoids and their biozonation across the Santonian-Campanian boundary in north-eastern Coahuila, Mexico, Palaeontologia Electronica (a 34) 24 (3), pp. 1-62 : 50-51

Scaphites (Scaphites) hippocrepis ( DeKay, 1828) III Cobban, 1969

Figure 39A–P

1828 Ammonites hippocrepis Dekay , p. 273, plate 5, figure 5.

1969 Scaphites hippocrepis (DeKay) III ; Cobban, plate 3, figures 1-25; plate 4, figures 35-49; plate 5, figures 36-40; text figures 2, 4, 10, 11 (with synonymy)

1986 Scaphites (Scaphites) hippocrepis ( Dekay, 1828) ; Kennedy, p. 118, plate 13, figure 5; plate 19, figures 1-34; plate 20, figures 1-6, 9, 1 O; plate 21, figures 1-11; plate 23, figures 2, 3 (with synonymy)

1992 Scaphites (Scaphites) hippocrepis (Dekay) III ; Cobban and Kennedy, p.

451, figures 4.1-4.3, 4.13-4.20, 4.22- 4.23, 4.28, 4.92, 6.1-6.4, 6.10, 7.2

1993 Scaphites (Scaphites) hippocrepis ( Dekay, 1828) ; Kennedy and Cobban, p. 845, figures 15.1, 17.1-17.32

1995 Scaphites (Scaphites) hippocrepis ( Dekay, 1828) form III; Jagt, Burnett and Kennedy, p. 57, plate 3, figure 3

1996 Scaphites (Scaphites) hippocrepis ( Dekay, 1828) , form III of Cobban, 1969; Kennedy and Christensen, p. 115, figure 32

2000a Scaphites hippocrepis (Dekay) III ; Küchler, plate 8, figures 3-6

2004 Scaphites (Scaphites) hippocrepis ( Dekay, 1828) , III sensu Cobban, 1969; Jagt, Walaszczyk, Yazykova, and Zaton, p. 577, plate 1, figure 4

2005 Scaphites hippocrepis ( Dekay, 1828) , Kaplan et al., p. 138, plate 57, figures 1- 30; plate 58, figures 1-15; plate 62, figure 5 (with synonymy)

?2013 Scaphites sp. ex gr. S. hippocrepis ( DeKay, 1828) ; Ifrim et al., p. 895, figures 9.23-9.28, 12.1-12.15, table 7

Type. Neotype, designated by ( Kennedy, 1986, p. 118), is no. 19483 in the collections of the Philadelphia Academy of Sciences. It is the holotype of Scaphites cuvieri Morton, 1834, p. 109 , p1. 7, figure 1, refigured by Whitfield, 1892, p1. 44, figure 8, Richards, 1953, text-figure 224, and Reeside, 1962, p1. 71, figures 1-5. The specimen is from the deep cut of the Chesapeake and Delaware Canal, Delaware.

Material. Two specimens, CPC –2599 and –2600, both from bed TPY732 .

Description. Inflated to globular whorl section. WB/WH is <1.76 in juveniles but decreases to 1.03 in shells with D> 16 mm. Maximum width is reached at mid-flank. The expansion rate is high in early growth stages but decreases at larger diameters, as indicated by similar WBs of the early and later whorl. The final whorl section grades towards a subtriangular shape. U is small, with U/D decreasing from 0.2 in early juveniles to 0.1 at large D. The umbilicus is deep. Umbilical walls are rounded and grade into rounded flanks, which are short due to a widely rounded venter. Eight tubercles are present per half whorl and give rise to bullae that each grade into pairs of moderately prorsiradiate convex ribs. These are occasionally intercalated by secondaries, resulting in ca. 17 primaries and secondaries per half whorl. The suture is simple, with shallow, subrectangular, asymmetrically bifid elements. Only E/L and L are asymmetrically trifid.

Dimensions. CPC–2599, D: 17.0; CPC–2600, D: 21.5, WB: 12.0 (0.6), WH: 8.0 (0.4), WB/WH: 1.50, U: 6.0 (0.28), ribs per whorl: 38.

PALAEO- ELECTRONICA.ORG

Remarks. Ornament, particularly the type of ribbing, relates our specimens to morphotype III of S. hippocrepis . This morphotype is the most widespread which provides good biostratigraphic control in both North America and Europe. Size differences exist between CPC–2599 and –2600 and suggest that the two represent a micro- and a macroconch.

Occurrence. In North America S. hippocrepis III is known from the middle lower Campanian of the Western Interior, Gulf Coast and Atlantic Coast Plan ( Cobban, 1969; Cobban and Kennedy, 1992 a, 1992b), western Coahuila ( Ifrim et al., 2013) ( Pervinquière, 1907), and the North American Pacific coast ( Anderson, 1958). Records are also from France ( Kennedy, 1986), Poland, Germany, and Netherlands ( Jagt et al., 2004; Kaplan et al., 2005), Sweden ( Kennedy and Christensen, 1997), and Tunisia. Lower middle Campanian records of S. hippocrepis III also exist from Spain ( Küchler, 2000) and Germany ( Kaplan et al., 2005).

Figures

FIGURE 39. Scaphites (S.) hippocrepis III from bed TPY73 of the Tepeyac section. A–D, I–L: CPC–2599; E–H, M–P: CPC–1600, both from bed TPY72. Scale: 50 mm.