359
amorphous body comparable to rhizocephalan barnacles (see below) with a nutrientabsorbing network embedded inside the host and an external egg sac (already known
for quite a while, see Lankester 1880).
After hatching as nauplius larva, they metamorphose after up to six stages into a
copepodid (Boxshall 1990b). Most parasitic copepodids attach to their host and
develop through up to five copepodid stages. If the adult parasitic copepodan is an
obligate parasite, the female is permanently anchored into the host by claw-like
head appendages, a modified ventral body surface or appendages, or a combination
of it, whereas the smaller males hold onto the females (Boxshall 1990b).
10.4.2 Phylogenetic Inference of Appearance and Molecular
Estimations of Early Evolution
The molecular data still provide no clear phylogenetic position of Copepoda
within Eucrustacea, and no convergence with morphological data has been
achieved yet (e.g., Huys and Boxshall 1991; Regier et al. 2005; Eyun 2017;
Khodami et al. 2017). Apparently, the parasitic groups within Copepoda evolved
parasitism independently (Huys and Boxshall 1991; Boxshall and Halsey 2004;
Boxshall et al. 2005). Within these parasitic groups, also changes to a non-parasitic life style have been inferred, e.g. in Siphonostomatoida or Cyclopoida (Huys
and Boxshall 1991).
10.4.3 Fossil Representatives
Probably due to their small size, fragility and cryptic nature, parasitic copepods
have a scarce fossil record; only few body fossils of parasitic copepods have been
found. The oldest fossil remains (supposed fragments of antennae and maxillulae)
of representatives of Copepoda (though without hints on their life habits) have been
reported from the Carboniferous (303 mya; Selden et al. 2010). However, Andres
(1989) depicted several presumed parasitic crustaceans from the Ordovician of
Sweden (c. 470 mya), which possess a sucking mouth cone and biramous swimming appendages closely reminding of those of copepods (Fig. 10.5b).
Kabatarina pattersoni from the Cretaceous Santana Formation of Serra do
Araripe, Brazil (120–110 mya) is known from two complete female specimens from
two fish skulls (direct host-parasite association) (Figs. 10.5a and 10.6; Cressey and
Patterson 1973) and 13 more fragmented specimens, apparently including parts of
males (Cressey and Boxshall 1989). Although the latter record displays only fragments, these were attached to the skull of a fish, hence we consider the record as
direct indication for parasitism. Another possible parasitic copepodan is one specimen attached to a shrimp-like tanaidacean crustacean in amber from the Lower
Cretaceous of Spain (Vonk and Schram 2007).
10 Evolutionary History of Crustaceans as Parasites
amorphous body comparable to rhizocephalan barnacles (see below) with a nutrientabsorbing network embedded inside the host and an external egg sac (already known
for quite a while, see Lankester 1880).
After hatching as nauplius larva, they metamorphose after up to six stages into a
copepodid (Boxshall 1990b). Most parasitic copepodids attach to their host and
develop through up to five copepodid stages. If the adult parasitic copepodan is an
obligate parasite, the female is permanently anchored into the host by claw-like
head appendages, a modified ventral body surface or appendages, or a combination
of it, whereas the smaller males hold onto the females (Boxshall 1990b).
10.4.2 Phylogenetic Inference of Appearance and Molecular
Estimations of Early Evolution
The molecular data still provide no clear phylogenetic position of Copepoda
within Eucrustacea, and no convergence with morphological data has been
achieved yet (e.g., Huys and Boxshall 1991; Regier et al. 2005; Eyun 2017;
Khodami et al. 2017). Apparently, the parasitic groups within Copepoda evolved
parasitism independently (Huys and Boxshall 1991; Boxshall and Halsey 2004;
Boxshall et al. 2005). Within these parasitic groups, also changes to a non-parasitic life style have been inferred, e.g. in Siphonostomatoida or Cyclopoida (Huys
and Boxshall 1991).
10.4.3 Fossil Representatives
Probably due to their small size, fragility and cryptic nature, parasitic copepods
have a scarce fossil record; only few body fossils of parasitic copepods have been
found. The oldest fossil remains (supposed fragments of antennae and maxillulae)
of representatives of Copepoda (though without hints on their life habits) have been
reported from the Carboniferous (303 mya; Selden et al. 2010). However, Andres
(1989) depicted several presumed parasitic crustaceans from the Ordovician of
Sweden (c. 470 mya), which possess a sucking mouth cone and biramous swimming appendages closely reminding of those of copepods (Fig. 10.5b).
Kabatarina pattersoni from the Cretaceous Santana Formation of Serra do
Araripe, Brazil (120–110 mya) is known from two complete female specimens from
two fish skulls (direct host-parasite association) (Figs. 10.5a and 10.6; Cressey and
Patterson 1973) and 13 more fragmented specimens, apparently including parts of
males (Cressey and Boxshall 1989). Although the latter record displays only fragments, these were attached to the skull of a fish, hence we consider the record as
direct indication for parasitism. Another possible parasitic copepodan is one specimen attached to a shrimp-like tanaidacean crustacean in amber from the Lower
Cretaceous of Spain (Vonk and Schram 2007).
10 Evolutionary History of Crustaceans as Parasites