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Probable root structures and associated trace fossils from the Lower Pleistocene calcarenites of Favignana Island, southern Italy... 751

Fig. 7. Example of roots of recent trees

A – silk floss tree (Ceiba specios; palo borracho), Huelva, southern Spain; B – unknown deciduous tree, Pimai, Thailand; C – pine (Pinus sp.), Sankt
Petersburg region, Russia; D – willow (Salix sp.), Sankt Petersburg region, Russia

M a t e r i a l. – The holotype (Fig. 8A) was left in the field most parallel (Fig. 8C). Very rarely dichotomous second-order
because its collection, would require the cutting of a large rock branches occur (Fig. 8C). Some of the associated trace fossils
slab. Moreover, six specimens in the field are documented by do not display branches at exposure (Fig. 8E). They resemble
photographs at site 4 (Frascia, S of cemetery; GPS coordinates: the animal trace fossil Skolithos or Macanopsis (those with en-
N37°56.036’; E012°20.945’; ±5 m), site 5 (GPS coordinates: largements at the base, see Fig. 9); however, their size and pres-
N37°56.170’; E012°20.624’; ±6 m), and site 6 (Cavallo 1). ervation suggest that they belong to E. rectibrachiatus, where
branches are not visible in some sections.
D i a g n o s i s. – Vertical shaft with simple, straight,
branches running obliquely downwards. The branches are el- D i s c u s s i o n. – The tapering down, smaller width of
liptical in cross-section and of smaller dimension than the shaft. the side branches and dichotomous diverging downwards are
features typical of roots (cf. Klappa, 1980). Smaller roots of the
D e s c r i p t i o n. – Sub-vertical, almost straight or same morphology from the Eocene have been illustrated by
slightly winding central cylindrical structure without wall or Plaziat (1971, fig. 3). The locally present lining, which is com-
only with a thin lining, smooth, up to at least 110 cm long, ir- posed of finer limestone than the filling and the surrounding
regularly tapering down. Some specimens, including the rock, probably represents a root tubule, with the tubule having
holotype (Fig. 8A), display gentle swellings and constrictions formed as a cementation envelope around roots (Klappa,
from 25 to 30 mm, at intervals of 15–25 cm. The central cylin- 1980). Any known crustacean or other animal burrow does not
der displays rare, straight, simple, tubular branches, circular or display a similar pattern. Because of its size and pattern,
elliptical in cross-section, mostly 5–8 mm wide, rarely up to Egadiradixus rectibrachiatus is interpreted as a cast of taproot
20 mm wide, up to 120 mm long, running downwards at the an- of a higher plant, probably a tree or a bush. The voids after de-
gle ranging from 15 to 40° with respect to the horizontal plane. cayed roots may have been filled by calcarenite brought in by
In one case, the central structure diverges downwards at a very marine flooding.
low angle and passes into two cylindrical structures running al-