holothurians (69.64 %) are from the depth range 0–50 m. There are no records
from the range 200–499 m. Eight families of holothurians are only found in
shallow waters down to a maximum depth of 199 m. Representatives of four
families (Deimatidae, Molpadiidae, Psychropotidae and Synallactidae) have only
been found at depths deeper than 500 m.
7.4 Paleontology
Paleontological studies of echinoderms in Venezuela were initially developed in
the 1920s, as a supplementary component during the initiation of petroleum
exploration. The lack of knowledge at that time about the Venezuelan sedimentary
basins prevented the stratigraphic location of areas with fossil accumulations as
they are known today (Fig. 7.3). In addition, the limited attention to echinoderms,
being considered among the so called miscellaneous groups due to their apparent
lack of importance as paleo-stratigraphic markers, decreased the interest for
research on this group of fossils.
Early geological expeditions to Venezuela by P. Christ, C. Wiedenmayer,
Vonderschmitt and H.G. Kugler between 1921 and 1926 provided some specimens
for this study. Also, J. Nance in 1941 and D. Rusk in 1954, among several other
anonymous contributors, added specimens to the invertebrate survey from Venezuela.
Later taxonomic studies, based upon the first collections, led Jeannet (1928),
Cooke (1941, 1961), Anisgard (1954), Von der Osten (1957), Weisbord (1969),
Hoover (1981) and Mooi and Peterson (2000) to the formal classification of the
first fossil species of Venezuelan echinoderms. Mihaljevic ´ et al. (2010) placed the
study of fossil echinoderms in the paleoecological and paleobiogeographical
context, which emphasizes the importance of the study of fossil echinoderms for
the paleoenvironmental interpretation.
It should be emphasized, that the data provided in geological order in the
following section of paleoenvironmental descriptions are based on the Stratigraphic Lexicon of Venezuela of the Venezuelan Ministry of Energy and Mines
(Ministerio de Energía y Minas 1997). This is also referred to in the web site
(http://www.pdv.com/lexico) as Venezuelan Geologic Code, and has been developed from Venezuelan fossil echinoderms references and records based on our
own field in situ collections (Fig. 7.4) and specimens from museum collections.
7.4.1 Permian
The earliest record of echinoderms in Venezuela is a species of undetermined
Cidaroida collected in the Palmarito Formation of Zulia state (Hoover 1981). This
corresponds to a paleoenvironment of transitional sedimentation between shallow
waters of variable salinity, and deeper waters with constant marine salinity.
252
C. Lodeiros et al.
from the range 200–499 m. Eight families of holothurians are only found in
shallow waters down to a maximum depth of 199 m. Representatives of four
families (Deimatidae, Molpadiidae, Psychropotidae and Synallactidae) have only
been found at depths deeper than 500 m.
7.4 Paleontology
Paleontological studies of echinoderms in Venezuela were initially developed in
the 1920s, as a supplementary component during the initiation of petroleum
exploration. The lack of knowledge at that time about the Venezuelan sedimentary
basins prevented the stratigraphic location of areas with fossil accumulations as
they are known today (Fig. 7.3). In addition, the limited attention to echinoderms,
being considered among the so called miscellaneous groups due to their apparent
lack of importance as paleo-stratigraphic markers, decreased the interest for
research on this group of fossils.
Early geological expeditions to Venezuela by P. Christ, C. Wiedenmayer,
Vonderschmitt and H.G. Kugler between 1921 and 1926 provided some specimens
for this study. Also, J. Nance in 1941 and D. Rusk in 1954, among several other
anonymous contributors, added specimens to the invertebrate survey from Venezuela.
Later taxonomic studies, based upon the first collections, led Jeannet (1928),
Cooke (1941, 1961), Anisgard (1954), Von der Osten (1957), Weisbord (1969),
Hoover (1981) and Mooi and Peterson (2000) to the formal classification of the
first fossil species of Venezuelan echinoderms. Mihaljevic ´ et al. (2010) placed the
study of fossil echinoderms in the paleoecological and paleobiogeographical
context, which emphasizes the importance of the study of fossil echinoderms for
the paleoenvironmental interpretation.
It should be emphasized, that the data provided in geological order in the
following section of paleoenvironmental descriptions are based on the Stratigraphic Lexicon of Venezuela of the Venezuelan Ministry of Energy and Mines
(Ministerio de Energía y Minas 1997). This is also referred to in the web site
(http://www.pdv.com/lexico) as Venezuelan Geologic Code, and has been developed from Venezuelan fossil echinoderms references and records based on our
own field in situ collections (Fig. 7.4) and specimens from museum collections.
7.4.1 Permian
The earliest record of echinoderms in Venezuela is a species of undetermined
Cidaroida collected in the Palmarito Formation of Zulia state (Hoover 1981). This
corresponds to a paleoenvironment of transitional sedimentation between shallow
waters of variable salinity, and deeper waters with constant marine salinity.
252
C. Lodeiros et al.