Gymnocodium, Pia, 1920 emend. Elliott, 1955

Vachard, D, Krainer, K & Lucas, SG, 2015, Late Early Permian (late Leonardian; Kungurian) algae, microproblematica, and smaller foraminifers from the Yeso Group and San Andres Formation (New Mexico; USA), Palaeontologia Electronica (English ed.) 3 (8), pp. 1-77 : 16-18

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https://doi.org/ 10.26879/433

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lsid:zoobank.org:pub:76D74301-4F2F-4A01-ADE5-EF52F8B53659

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https://treatment.plazi.org/id/03F9582F-FD54-FFEA-FC7E-F99136DCFBFA

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scientific name

Gymnocodium
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Gymnocodium View in CoL ? johnsonii n. sp.

Figures 10.9, 10.10 View FIGURE 10. 1-3 , 11.8, 11.9 View FIGURE 11. 1-4, 6-7 , 14.6, 14.7, 14.11 View FIGURE 14. 1-4, 10 , 15.3, 15.5, 15.6-15.8, 15.10, 15.11 View FIGURE 15. 1-2, 4, 7, 9 , 16.3-16.5, 16.7, 16.9 View FIGURE 16. 1-2, 6, 8 , 17.5, 17.8, 17.9 View FIGURE 17. 1-4, 7 , 18.11 View FIGURE 18. 1-5 , 19.1, 19.2, 19.4-19.6, 19.9 View FIGURE 19. 1-2, 4-6, 9 , 20.17, 20.19 View FIGURE 20. 1-4

zoobank.org/ BCE369DB-86A5-45C7-8EAA-073A16E94617

? 1965 Gymnocodium bellerophontis (Rothpletz) ; Johnson and Kaska, p. 64, pl. 1, figs. 1, 2, 3, 4.

? 1965 Permocalculus cf. tenellus Pia ; Johnson and Kaska, p. 64-65, pl. 2, fig. 1.

? 1993 Gymnocodium ; Li and Mamet, fig. 4F.

? 2005 Gymnocodium ; Mamet and Zhu, fig. 6H.

v. 2013 b Gymnocodium ; Lucas, Krainer and Voigt, fig. 8 H, J .

v. 2013 Gymnocodiacean algae; Brose, Lucas and Krainer, fig. 6.1, 6.3.

v. 2013 Gymnocodium ; Brose, Lucas and Krainer, fig. 6.9.

v. 2013 b Gymnocodium sp. 1 ; Vachard, Krainer and Lucas, p. 348 (no illustration).

Etymology. In memory of J.H. Johnson for his fundamental work on the North American algae.

Holotype. NMMNH P-67509; Figure 10.9 View FIGURE 10. 1-3 ; sample MG (2) 12-12.

Paratypes. NMMNH P-67510, 67511, 67512; Figures 10.10 View FIGURE 10. 1-3 , 11.8-9 View FIGURE 11. 1-4, 6-7 .

Material. 275 specimens.

Locus Typicus. NMMNH locality 8893; Yeso Group, Los Vallos Formation, Torres Member, Massacre Gap in the southern Fra Cristobal Mountains (New Mexico).

Stratum Typicum. Early? Kungurian (late Leonardian).

Diagnosis. A Gymnocodium ? characterised by some constrictions of the thallus, a poorly individualized medullar zone, and curved cortical siphons with large deltoid terminations.

Description. Thallus moderately large (L = 1.13- 4.50 mm, w = 0.45-3.00 mm), and periodically but asymmetrically compressed. Medullar zone generally sparitized and poorly individualized from the cortical zone. This cortical zone is relatively wide and crossed by euspondyl, curved, thin siphons, with terminal deltoids equilaterally triangular and relatively wide (0.05-0.07 (0.09) mm). Conceptacles not observed.

Comparisons. Gymnocodium ? johnsonii n. sp. differs from the typical Gymnocodium by the characters indicated above. From the rare moniliform Gymnocodium as such as G. nodosum ( Ogilvie-Gordon, 1927) Bilgütay, 1959 , it differs by larger dimensions (w = 1.27-2.40 mm in this latter species; see Roux, 1991), irregular swelling (against regular barrel-like segments), and less deep deltoid terminations. It differs from Siamporidium elongatum Endo, 1969 by a less elongate test and less ramified cortical siphons.

The new taxon Gymnocodium ? johnsonii n. sp., as one of the oldest representatives of the Gymnocodiaceae , may represent a missing link between an ancestral Boueina -like codiacean or Nanjinophycus -like gymnocodiaceans and the true gymnocodiaceans; i.e., Gymnocodium and Permocalculus . Nevertheless, Permocalculus Elliott, 1955 might correspond to another branch of this lineage, because its FAD is possibly located as early as the Sakmarian (see, Homann, 1972, plate 1, figure 8; identified as Gymnocodium cf. gracile Kordé ) or the early Wolfcampian ( Buitrón-Sanchez et al., 2012); i.e., prior to the first occurrence of Gymnocodium ? johnsonii n. sp.

Occurrence. Kungurian (late Leonardian) of New Mexico (Yeso Group, Torres Member: samples MG 10-13, MG(2) 10-15, MG(2) 12-3, MG(2) 12-4, MG 12-4a, MG(2) 12-5, MG(2) 12-8, MG 12-9, MG(2) 12-12, MG(2) 12-13, MG(2) 12-14, MG 13e; San Andres Formation, McLeod Hills, lower part (MLY) and reference sections (SAR): samples MLY 5-26, MLY(2) 5a-12, MLY(2) 5-13, MLY(2) 6-5, MLY 6-6, MLY(2) 6-6, MLY 6-7, MLY 6-11, MLY 6-12, MLY(2) 6-14, MLY(2) 6-15, MLY(2) 6-17, MLY(2) 6-18, MLY(2) 6-19, MLY(2) 6-20, MLY(2) 6-22, MLY 6-25, MLY 6-27, MLY 6-32, MLY 8-5, SAR 2-1, SAR 2-2, SAR 2-3, SAR 2-4, SAR 7-8, SAR 7-9, SAR(2) 8-7/ 8-17, SAR(2) 8-11, SAR 8-15, SAR 8a-15, SAR 8a- 16, SAR 8a-25)). Possibly present in the Artinskian-Kungurian (Leonardian) of Guatemala and in the Lower Permian of South China ( Li and Mamet, 1993) and North China ( Mamet and Zhu, 2005).

H

University of Helsinki

J

University of the Witwatersrand

NMMNH

New Mexico Museum of Natural History and Science

MG

Museum of Zoology

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