Caudicriodus alcoleae (Carls, 1969)

Drygant, Daniel & Szaniawski, Hubert, 2012, Lochkovian conodonts from Podolia, Ukraine, and their stratigraphic significance, Acta Palaeontologica Polonica 57 (4), pp. 833-861 : 848-849

Caudicriodus alcoleae (Carls, 1969)

Fig. 10K.

1969 Icriodus angustoides alcoleae n. ssp.; Carls 1969: 326, pl. 1: 12; pl. 2: 1–2.

1976 Caudicriodus angustoides alcoleae (Carls, 1969) ; Bultynck 1976: 34, pl. 4: 14, 18–28; text−fig. 2.

1980 Icriodus woschmidti hesperius Klapper and Murphy ; Schönlaub 1980a: pl. 19: 1, 12.

1994 Icriodus angustoides alcoleae Carls ; Valenzuela−Ríos 1994: 93, pl. 8: 9–10, 12–13, 18, 27, 34.

2002 Icriodus angustoides alcoleae Carls ; García−López et al. 2002: pl. 1: 11, 12.

2002 Icriodus angustoides aff. alcoleae Carls ; García−López at al. 2002: pl. 1: 13.

2003 Caudicriodus angustoides alcoleae (Carls) ; Bultynck 2003: pl. 4: 12, 13.

?non 2012 Icriodus angustoides alcoleae Carls ; Slavík et al. in press: fig. 6: 16 [=? C. schoenlaubi sp. nov.].

Material.—One Pa element from Mytkiv Formation, sample 45/ 175 m.

Remarks.—Specimen is characterized by tear−shaped, short and strongly convex platform with short spindle and lack of spur. Denticles of the transverse ridges in the lateral rows have circular base, are big and cone−shaped. Denticles of the median row are lower, joined by thin margins with themselves and with lateral denticles. Postero−lateral process short, undenticulated. The angle between median longitudinal row and postero−lateral process is about 130 °. The primary cusp much bigger than the secondary.

This specimen is similar to the specimens illustrated by Bultynck (2003: pl. 1: 12, 13) from Pedavis pesavis Zone in Guadarrama and to the specimens illustrated by García−López et al. (2002: pl. 1: 11, 12) from Caudicriodus alcoleae Zone in Northwest Spain but differs from them by typical icriodontan denticulation on the spindle.

Stratigraphic and geographic range.— Caudicriodus transiens Zone in Podolia, lower Lochkovian in Barrandian, Ancyrodelloides delta and Pedavis pesavis Zones in Pyrenees, Carazo and Lebanza Formations (lower and middle Lochkovian) of Northwesern Spain, middle Lochkovian of Guadarrama Mountains ( Spain).

Caudicriodus postwoschmidti (Mashkova, 1968) Figs. 9D , 10O, P, 11A, B.

For synonymy see Drygant (2010) and include:

1968 Icriodus eolatericrescens sp. n.; Mashkova 1968b: 942 [partim], fig. 1: 4–5 [juvenile form].

1968 Icriodus woschmidti postwoschmidti ssp. n.; Mashkova 1968b: 943, fig. 1: 1–3 [mature form].

1985 Icriodus sp. n. A; Schönlaub 1985: pl. 2: 23 [only].

2004 Latericriodus steinachensis (Al−Rawi) beta morph Klapper and Johnson; Slavík 2004: pl. 1: 4.

2004 Latericriodus steinachensis (Al−Rawi) eta morph Klapper and Johnson Slavík 2004: pl. 1: 5.

2004 Latericriodus steinachensis (Al−Rawi) eta morph Klapper and Johnson; Slavík and Hladil 2004: 144, pl. 1: 4 [only].

2010 Caudicriodus postwoschmidti (Mashkova) ; Drygant 2010: 61, pls. 3: 16–18, 4: 1–3, 6, 7.

Material.—More than 50 complete Pa and 16 coniform elements from the Chortkiv Formation. Sections and samples: 18/5d, 13/1, 13A/2, 13/ 280 m, 81/ 370 m, 11B/1.

Remarks.—Among the Pa elements of this species “right” and “left” forms can be distinguished ( Fig. 9D ). Platform of the first one is triangular, elongated, widen behind the second (in juvenile specimens) or fourth (in adult specimens) transverse ridge. Platform of the second form shorter but wider than the first and has almost straight borders of the processes. Spindle comparatively elongated (0.7–0.9 mm), with 5–7 transverse ridges. The angle between the median row and postero−lateral processes do not exceeds 115–125 °. Denticles of the lateral rows bigger than those of the median row and connected in transverse ridges and in median row. Spur well developed, can be denticulated in gerontic specimens. Postero−lateral process triangular and bears a single ridge of denticles. Primary cusp is a little bigger than secondary one.

Specimens of the related species Caudicriodus woschmidti ( Ziegler, 1960) are characterized by elongated, less expanded platform and shorter postero−lateral process. Second related species C. hesperius ( Klapper and Murphy, 1975) differs by short, lobe−like extension of the platform, narrower postero−lateral process and by posession of the inner posterior lobe.

The specimens illustrated by Schönlaub (1980a: pl. 19: 2, 3) and also described by Mawson (1986: 44, pl. 9: 1, 2) as Icriodus postwoschmidti are close in outline of platform and short triangular postero−lateral process to the transitional forms between Caudicriodus woschmidti ( Ziegler, 1960) and C. hesperius ( Klapper and Murphy, 1975) . The specimens assigned to the species by Colquhoun (1995: pl. 1: 2, 3) and by Barrick et al. (2005: pl. 3: 9, 10, 12) have short, lobe−like extended platform with separated and well−developed outer and inner lobes. This feature is characteristic for C. hesperius , but not for the discussed species. The Pa elements described as Icriodus postwoschmidti by Barrick and Klapper (1992: 45, pl. 3: 7–12) and by Farrell (2003: 124, pl. 2: 1, 2) are closest in morphology to the Caudicriodus hesperius . They distinctly differ from C. postwoschmidti by the lobe−like platform.

Pa element from Barrandian identified by Slavík (2004: pl. 1: 4) as “ Latericriodus steinachensis (Al−Rawi) eta morphotype Klapper and Johnson” represents the “right” form of the element in Caudicriodus postwoschmidti . Second specimen from Barrandian identified by Slavík (2004: pl. 1: 5) and described by Slavík and Hladil (2004: 144, pl. 1: 4) as “ L. steinachensis ( Al−Rawi, 1977) eta morph Klapper and Johnson” represents the “left” form of the element in Caudicriodus postwoschmidti . The elements have similar shape of platform and denticulation. Specimen of the “eta morphotype” is Lochkovian in age, probably from Pedavis pesavis Zone (see Slavík [2004: fig. 3 and table 2] and Slavík and Hladil [2004: figs. 2, 3, 4]). Age of the “beta morphotype” is uncertain.

Stratigraphic and geographic range.— Caudicriodus postwoschmidti Zone (middle Lochkovian) in Podolia, upper Lochkovian in Cantabrian Mountains, Carnic Alps, and Barrandian.

Figures

Fig. 9. Ontogenetic development and morphological comparison of Pa elements of Podolian Caudicriodus species.