- monophyletic) group.
Chasmataspidids survived at
least since Ordovician to mid-Devonian in age. As of 2019, most
chasmataspidids (with a
total of 9 species)...
- crabs) and
Planaterga (a
group comprising bunodids, pseudoniscids,
chasmataspidids,
eurypterids and arachnids), as well as
several basal synziphosurid...
-
number of
extinct lineages, such as the
eurypterids (sea scorpions) and
chasmataspidids.
Chelicerata split from
Mandibulata by the mid-Cambrian, as evidenced...
- existed, and the two may be
sister groups. The difficult-to-classify
chasmataspidids are also
thought to be
closely related to
horseshoe crabs. The radiation...
- pseudoniscids) and the
group Dekatriata (which in turn
includes arachnids,
chasmataspidids and eurypterids).
Planaterga is
defined by the
opisthosoma with tergites...
- for the latter).
Unlike most of
dekatriatans like
eurypterids and
chasmataspidids, the
metastoma (ventral
plate in
front of opisthosoma) of
Houia is...
-
indicates length of
animal 77.4–85.1 cm (30.5–33.5 in). The
largest chasmataspidids were the
Ordovician Hoplitaspis at 29 cm (11 in) in
length and similar...
-
inside the
clade Planaterga alongside Pseudoniscidae and
Dekatriata (
chasmataspidids,
eurypterids and arachnids).
Bunodidae is
composed by two genera, Bunodes...
-
Early Ordovician deposits of Tennessee,
United States. Just like
other chasmataspidids, the body of
Chasmataspis compose of a
prosoma and a 13-segmented opisthosoma...
-
classified inside the
clade Planaterga,
alongside Bunodidae and
Dekatriata (
chasmataspidids,
eurypterids and arachnids).
Pseudoniscidae is
composed by two genera...
