Zamites diquiyui (Wieland), 1982

León, María Patricia Velasco de, Martínez, Erika Lourdes Ortiz, Barragan, Miguel Angel Flores, Madrid, Diana Silvia Guzmán & Martinez, Pedro Christian Martínez, 2024, New records of Bennettitales and associated flora from the Jurassic of the Cualac Formation, Mexico, Palaeontologia Electronica (a 14) 27 (1), pp. 1-19 : 10

publication ID

https://doi.org/ 10.26879/1293

persistent identifier

https://treatment.plazi.org/id/1B6F87DA-FFDF-FFC9-391C-BCD55215FC60

treatment provided by

Felipe

scientific name

Zamites diquiyui (Wieland)
status

 

Zamites diquiyui (Wieland)

Person et Delevoryas, 1982

Figure 3 View FIGURE 3 D-H

1914 Otozamites or Zamites Wieland , pl.19, figs. 6, 7.

1914 Otozamites (Otopteris) sp. Wieland, pl. 44, fig. 2.

1982 Zamites diquiyui Person and Delevoryas , pl. 6, fig. 39.

Holotype. IGPB 420 . U. of Texas P. C. No. 164

Epitype. CCr10-1

Type locality. Rosario, Cualac Formation

Age. Lower-Middle Jurassic

Deposited. Facultad de Estudios Superiores Zaragoza , Universidad Nacional Autónoma de México .

Material examined. CFZ Cr. 1-3, Cr4-9, Cr9-4, Cr10-1, Cr20-1, Cr24-4, Cr28-6, Cr28-11, Cr31-1, 3, and 4, Cr40-2, Cr42-10, Cr45-1, Cr46-1, Cr51-8, Cr55-1, Cr58-3, Cr62-1 and 2, Cr64-1, Cr66-2, Cr73-2, Cr76-3, Cr78-3, Cr82-5, Cr84-2, Cr94-1 and 2, Cr95-1, Cr97-5, 6, 7, and 8, Cr98-1, Cr114- 3, and Cr120-1, Cr123-1,

Emended diagnosis. Compound leaves, leaflet entire-margined, base cordate even quadrate, acute apex, inserted to the rachis by the central part of the base, and sub-oppositely arranged. Fine and robust occasionally bifurcating veins. Cuticle with syndetocheilic stomata, with rectangular epidermal cells and hook-shaped trichomes.

Description. Elliptic leaf 26.5 cm long and 19.6 cm wide, rachis longitudinally striated and tapering towards the leaf apex with a maximum width of 0.4 cm. Leaflet sup-oppositely arranged, close together, 4.9–10.6 cm long and 1.7–3.5 cm wide ( Figure 3D View FIGURE 3 ). Acute apex, base cordate, quadrate in some cases ( Figure 3D View FIGURE 3 ). Pinnae laterally inserted to the rachis in angles of 80°–85°, robust veins at the base, widely spaced, at a density of seven-10 per leaflet, occasionally bifurcating once near the base. Two finer veins between the larger veins ( Figure 3E View FIGURE 3 ).

Cuticle with rectangular epidermal cells 6.4– 18.9 μm wide and 31.1–80.7 μm long, short, and elongated cells are interspersed, elongating, and thinning towards the rachis with a width of 4.2–6.7 μm and a length of 39.6–72.4 μm. Undulate to sinuous cell walls 1.4–6.2 μm wide, which are straight in the rachis and 0.5–1 μm wide ( Figure 3F View FIGURE 3 ). Dispersed simple, unicellular, hook-shaped trichomes 3–7 μm long with a rounded base 1.7–5.6 μm wide between the stomata, size increases in the veins to 30.1 μm in diameter at the base and up to 47.4 μm in length. Oval-rounded syndetocheilic stomata 14.6–20.9 μm wide and 19.9–25.2 μm long at the base, elongating towards the center to up to 38.7 μm. Open ostioles are 3–4.5 μm wide and 7.6–8.1 μm long and closed ostioles are 1–2.9 μm wide and 10.7–24.9 μm long. Guard cells are 1.5–2 μm wide and 5.1–9.8 μm long, subsidiary cells are 4.7–6.8 μm wide and 7.1–22.6 μm long ( Figure 3G View FIGURE 3 ).

Discussion. Given that the material used to establish Z. diquiyui is based only on poorly preserved isolated pinnae ( Person and Delevoryas, 1982, pl. 6, fig. 39), its description is ambiguous, and thus it was necessary to assign a new type with a higher number of morphological and cuticular characters, which were used for the emendation of the taxon.

Epitype CCr10-1 has compound leaves, pinnae with a symmetric base, and parallel veins that never anastomose, which are characters that allow corroborating its assignment to the genus Zamites ( Harris, 1969) . The species Z. oaxacensis , Z. lucerensis , and Z. tribulosus recorded in the Rosario locality ( Table 2) differ in leaf and pinna size and have a higher vein density, a variable vein arrangement, and lack trichomes.

U

Nationaal Herbarium Nederland

P

Museum National d' Histoire Naturelle, Paris (MNHN) - Vascular Plants

C

University of Copenhagen

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