Jaekelotodus trigonalis (Jaekel, 1895)

Kovalchuk, Oleksandr, Kriwet, Jürgen, Shimada, Kenshu, Ryabokon, Tamara, Barkaszi, Zoltán, Dubikovska, Anastasiia, Anfimova, Galina & Davydenko, Svitozar, 2023, Middle Eocene cartilaginous fishes (Vertebrata: Chondrichthyes) of the Dnieper-Donets Basin, northern Ukraine, Palaeontologia Electronica (a 32) 26 (2), pp. 1-37 : 12-14

publication ID

https://doi.org/ 10.26879/1283

persistent identifier

https://treatment.plazi.org/id/A1525343-662F-FF9E-FC0A-B5DCFE3FFCE6

treatment provided by

Felipe

scientific name

Jaekelotodus trigonalis (Jaekel, 1895)
status

 

Jaekelotodus trigonalis (Jaekel, 1895)

Figure 5A–F View FIGURE 5

1861 Lamna cuspidata Ag. ; Rogovich, p. 46,

pl. VI, figs. 7-14b.

1861 Lamna denticulata Ag. ; Rogovich, p. 47, pl. VI, figs. 15-23.

1895 Hypotodus trigonalis n. sp.; Jaekel, pl. 1, figs. 6, 7.

1912 Lamna (Odont.) crassidens Ag. 1843; Savtchenko, p. 177-178, pl. XIII, figs. 20- 23.

1928 Iekelotodus trigonalis (Iek.) ; Menner,

p. 315.

1964 Jaekelotodus trigonalis (Jaekel) minor Gluckman ; Glickman, p. 137, pl. XVIII, figs. 32, 33, 40-42, 44, 45; pl. XIX, figs. 1-3.

1964 Jaekelotodus trigonalis (Jaekel) medius Gluckman; Glickman, p. 137, pl. XIX, figs. 4, 5, 7, 8, 11-13, 18.

1964 Jaekelotodus trigonalis trigonalis (Jaekel) ; Glickman, pl. XIX, figs. 15-17, 20-22.

1988 Hypotodus trigonalis (Jaekel) ; Nolf, p. 114, pl. 29, figs. 1, 2.

1994 Jaekelotodus trigonalis (Jaekel, 1895) ; Zhelezko and Kozlov, p. 110-112, pl. 1, figs. 1-2; pl. 2, figs. 1-3; pls. 37-39.

2005 Jaekelotodus trigonalis (Jaekel, 1895) ; Cappetta and Nolf, p. 247, pl. 6, figs. 1-4.

2006 Jaekelotodus trigonalis (Jaekel) ; Malyshkina, p. 99, pl. 9, figs. 3-5.

2006 Jaekelotodus trigonalis (Jaekel) ; Udovichenko, p. 202, pl. I, fig. 10.

2012 Jaekelotodus trigonalis (Jaekel, 1895) ; Cappetta, p. 200, fig. 189.

2012 Jaeckelotodus trigonalis (Jaeckel, 1895) ; Diedrich, p. 15, fig. 11.11-11.15.

2022 Jaekelotodus trigonalis ; Perez, p. 635,

fig. 4C.

Material. Six lateral teeth, NMNHU-G 391/62, 391/

139/1-5, Vyshhorod.

Description. The teeth ( Figure 5A–F View FIGURE 5 ) measure from 16.9 to 20.0 mm apicobasally (mean 19.0 mm) and from 19.5 to 21.5 mm mesiodistally (mean 20.2 mm). The main cusp is broad, with a curved tip, and has a concave, V-shaped cavity on its labial surface. Cutting edges are complete and progress into broad triangular primary cusplets. Secondary cusplets are also present, but they are smaller. Both pairs of cusplets are turned towards the main cusp, which has irregular and variably strong serrations near the base. On some of the specimens considered here, there are accessory denticles between the main cusp and lateral cusplets. The roots are massive and thickened labiolingually. The labial root surface is convex while the lingual is concave.

Remarks. The specimens described resemble those of Jaekelotodus trigonalis in overall morphology, although they are somewhat smaller. The teeth of Ypresian species ( J. londonensis Zhelezko, 1994 and J. borystenicus Glickman, 1964 ) have larger, narrower, and more erect crowns. Jaekelotodus trigonalis differs from J. robustus (Leriche, 1921) in having higher, sharper, and more lateral cusplets, as well as a less pronounced furrow at the top of the root (Cappetta and Nolf, 2005). It differs from the teeth of Hypotodus verticalis (Agassiz, 1843) by having complete cutting edges of the main cusp, which extend to the lateral cusplets. We need to stress that our identification is somewhat tentative: these specimens may also belong to or include similar odontaspidid taxa, such as Mennerotodus, Tethylamna , or Brachycarcharias .

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