Icriospathodus collinsoni ( Solien, 1979 )

Leu, Marc, Bucher, Hugo, Vennemann, Torsten, Bagherpour, Borhan, Ji, Cheng, Brosse, Morgane & Goudemand, Nicolas, 2022, A Unitary Association-based conodont biozonation of the Smithian-Spathian boundary (Early Triassic) and associated biotic crisis from South China, Swiss Journal of Palaeontology (19) 141 (1), pp. 1-61 : 43

Icriospathodus collinsoni ( Solien, 1979)

Fig. 25M, O, P

1964 Icriodus ; Clark et al., p. 376, pl. 60, fig. 1.

1970 Neospathodus n. sp. G; Haselmüller, p. 45–47, pl. 2, fig. 12a–b.

1971 Neospathodus n. sp. G; Sweet et al., p. 453, pl. 1, figs. 12, 13

*1979 Neospathodus collinsoni n. sp.; Solien, p.302, pl. 3, figs. 10, 12–20

1981 Neospathodus? collinsoni (Solien) ; Koike, pl. 1, figs. 42–44.

1987 Neospathodus collinsoni (Solien) ; Zakharov & Rybalka, p. 43–44, pl. 5, figs. 4, 5.

1990 Neospathodus collinsoni (Solien) ; Metcalfe, p. 136, pl. 1, figs. 6, 7, 17.

1992 Spathoicriodus collinsoni (Solien) ; Koike, p. 357–361, figs. 11, 12.13–12.42, 12.44, 12.47–12.50, 13.8–13.37.

1995 Icriospathodus collinsoni (Solien) ; Orchard, p. 113, fig. 2.22–2.24.

2005 Icriospathodus collinsoni (Solien) ; Orchard, p.96, fig. 22A

2007 Icriospathodus collinsoni (Solien) ; Orchard p.96, fig. 2

2007 Icriospathodus collinsoni (Solien) ; Lucas & Orchard, p. 123, figs. 7.4–7.7, 7.13–7.15.

2011 Icriospathodus collinsoni (Solien) ; Ji et al., p. 221, figs. 5a–5c.

2014 Icriospathodus collinsoni (Solien) ; Maekawa & Igo in Shigeta et al., p. 260, figs. 186.10–186.22, 187–191, 192.1–192.6.

2015 Icriospathodus collinsoni (Solien) ; Chen et al., p.113, figs. 9.1–9.4.

2015 Icriospathodus collinsoni (Solien) ; Yan et al., p. 240, figs. 3.5, 3.6.

2016 Icriospathodus collinsoni (Solien) ; Komatsu et al., p. 69, fig. 5.9.

2018 Icriospathodus collinsoni (Solien) ; Maekawa in Maekawa et al., p. 49–51, figs. 28.5–28.10, 29.1–29.7.

2019 Icriospathodus collinsoni (Solien) ; Chen et al., fig. 6, nr. 10–12.

2019 Icriospathodus collinsoni (Solien) ; Liu et al., p. 14, pl. 4, figs. 6–8.

2021 Icriospathodus collinsoni (Solien) ; Chen et al., figs. 4.9–11.

Number of specimens:>40

Description. A robust segminate P 1 element. Te upper edge bears biserial or/and ridge-like denticles. Te width of the denticles is usually longest in the middle part to the posterior third. Te basal cavity shows a lot of variation, but is mostly asymmetrical.

Remarks. Koike (1992) showed a wide range of intraspecific variation within this species (see below). Te two rows of nodes on the upper margin and the pairs of nodes connected by a ridge are diagnostic features that are easy to determine and miss-identification of even broken elements is unlikely. P 1 elements of Eurygnathodus are superficially similar but they are scaphate, not segminate.

Occurrence. I. collinsoni indicates the early Spathian worldwide and generally co-occurs with the Tirolites and Columbites beds. USA: Idaho, (Zone 11, Sweet et al., 1971), Utah (Taynes formation, Solien, 1979), Nevada ( Lucas & Orchard, 2007), South China ( Chen et al., 2015; Ji et al., 2011), Vietnam (Bac Tuy formation, Komatsu et al., 2016; Shigeta et al., 2014), Oman ( Orchard, 1995), Primorye ( Zakharov & Rybalka, 1987), Japan ( Maekawa et al., 2018), Malay Peninsula ( Metcalfe, 1990).

Figures

Fig. 25 Novispathodinae from Laren, Shanggang and Lilong. Magnification is ×80.The scale bar is 400 μm. All elements are considered to be P1 elements if not specifically identified otherwise. A–F, Icriospathodus zaksi (Buryi); A LAR205, PIMUZ 39170; B LIL508, PIMUZ 39171; C LIL508,PIMUZ 39172; D LAR204,PIMUZ 39173; E LIL510, PIMUZ 39174; F LAR203, PIMUZ 39175.G–L Icriospathodus aff. crassatus (Orchard); G LIL510, PIMUZ 39159; H LIL508,PIMUZ 39160; I LAR203, PIMUZ 39161; J LIL509, PIMUZ 39162; K LAR202,PIMUZ 39163; L LAR210, PIMUZ 39164.M, O, P Icriospathodus collinsoni (Solien); M SHA313,PIMUZ 39165; O SHA320,PIMUZ 39166; P LIL515A,PIMUZ 39167. N Triassospathodus symmetricus (Orchard); SHA320, PIMUZ 39319