Stratigraphy, Chronology And Palaeontology Of The Tertiary Rocks Of The Cheringoma Plateau, Mozambique
Author
Bamford, Marion
Author
Pickford, Martin
text
Fossil Imprint
2021
2021-12-09
77
1
187
213
http://dx.doi.org/10.37520/fi.2021.014
journal article
10.37520/fi.2021.014
2533-4069
7167141
Terminalioxylon mozambicense
sp. nov.
Text-fig. 16
H o l o t y p e. BP/16/1734 (
Text-fig. 16
).
P l a n t F o s s i l N a m e s R e g i s t r y N u m b e r.
PFN002687 (for new species).
A d d i t i o n a l m a t e r i a l. BP/16/1731, 1735, 1736,
1737.
R
e p o s i t o r y.
Curated
at the
Palaeobotany Herbarium
,
Evolutionary Studies Institute
(previously the Bernard Price Institute),
University
of the
Witwatersrand
,
Johannesburg
,
South Africa
(for both
holotype
and
additional material
)
.
E t y m o l o g y. The species name is for
Mozambique
with the latin suffix
ense
meaning “from”.
T
y p e l o c a l i t y. Mhengere Hill, Site 3 (
18°56′02.0″S
,
34°36′50.6″E
). Fossil wood associated with palaeopan, lower northwest slope (
Text-fig. 8
), probably late Eocene
.
D i a g n o s i s. The wood is diffuse porous and growth rings are absent to indistinct. Vessels are arranged in short radial multiples, often solitary but with lines of two or three pores. Some vessels are tylosed, and range in diameter from 145–175 µm (
Text-fig. 16a–c
). Perforation plates are simple and horizontal. Inter-vessel pits are alternate and 6–8 µm and vessel-parenchyma pits are the same (
Text-fig. 16a, b
). Parenchyma is scanty paratracheal to vasicentric and also diffuse (
Text-fig. 16a
). There are 2–4 cells per parenchyma strand. Prismatic crystals occur in the diffuse parenchyma cells and the ray cells (
Text-fig. 16d–g
). Rays are exclusively uniseriate and up to 16 cells high (175-400-500 µm), and procumbent body cells with 1–2 rows of marginal, square or upright cells that are difficult to see because of the dark cell contents (
Text-fig. 16i
). No canals were seen.
C o m p a r i s o n s. The
Gorongosa
wood is very similar to
Terminalioxylon tunesense
DUPÉRON- LAUDOUEN. described from the late Oligocene to early Miocene of
Tunisia
(DelteilDesneux 1981) except that the vessels of the
Gorongosa
wood are smaller, it has rare diffuse parenchyma with prismatic crystals, as well as crystals in the ray cells (like the Tunisian specimen). Vessel size is not a reliable taxonomic feature and the presence of diffuse parenchyma is easy to miss. The geographic separation of the two sites is considerable so in order to avoid unreliable phytogeographic correlations, the
Gorongosa
wood has been placed in a new species.
There are 57 examples of fossil
Terminalioxylon
woods listed in the InsideWood database but none of them is compatible with the
Gorongosa
wood samples. For example, only ten of the listed woods have diffuse parenchyma. Of these ten, only three have rays with only one row of upright marginal cells (
Terminalioxylon chiedense
,
T. coriaceum
and
T. felixii
).
Terminalioxylon chiedense
has wider rays, 1–2 cells with the uniseriate portion as wide as the multiseriate portion (
Fessler-Vrolant 1980
).
Terminalioxylon coriaceum
has some vessels more than 200 µm in diameter and confluent parenchyma (
Licht et al. 2014
).
Terminalioxylon felixii
has intervessel pits that are 10 µm wide, some confluent parenchyma, terminal parenchyma bands and tyloses (
Lakhanpal et al. 1984
). None of these described woods matches the
Gorongosa
woods.
Four other species of
Terminalioxylon
and one fossil
Terminalia
L. have been described from Tertiary rocks of Africa (
Terminalioxylon crystallinum
M.K.BAMFORD
and
Terminalioxylon orangense
M.K.BAMFORD
from the middle Miocene of
Namibia
(
Bamford 2003
);
Terminalioxylon welkitii
LEMOIGNE et J.BEAUCH.
from the Miocene of
Ethiopia
(
Lemoigne and Beauchamp 1972
);
Terminalia preglaucescens
BANDE, DECHAMPS, R.N.LAKH. et U.PRAKASH
from the early Miocene of
Zaire
(
Bande et al. 1987
)). The species vary slightly in average vessel diameters and degree of heterogeneity of the ray cells. None has diffuse parenchyma recorded.
Trees of the
Combretaceae
are common in southern Africa with members of
Combretum
and
Terminalia
being the most common. In
Mozambique
today there are about 11 species of
Terminalia
(out of a worldwide total of 150). Other genera include
Lumnitzera
,
Meiostemon
and
Pteleopsis
(
Burroughs et al. 2018
)
. Woods of the
Combretaceae
have been well studied (
van Vliet 1978
) and the genera are distinguishable. In
Mozambique
today there are ten species of
Terminalia
, all trees or shrubs, and their habitats range from rocky hillsides and ravines, Miombo woodland and forest to low altitude woodland (
Burroughs et al. 2018
). Extrapolating the environmental setting for the fossil wood from the modern analogues it is possible to infer that a tropical wooded environment was likely to be the setting.