324
Erynetidae feed on the blood of gastropods (snail mites) while others are haematophagous in the nasal cavities of amphibians and birds (André and Fain
2000). The entire superfamily potentially goes back to the Early Devonian
(Dunlop and Garwood 2018) with fossils assigned to Tydeidae, but the
Erynetidae (with parasitic species) lacks a fossil record.
3. Parasitengona is a cohort accommodating a substantial number of species,
including velvet mites, chiggers and water mites. They all share a particular
developmental strategy in which inactive and active juvenile stages alternate
with one another, and in which the larva—which is morphologically quite different from the adult—is active and parasitises invertebrate or vertebrate hosts,
see Wohltmann (2000) for a review. The larvae of water mites (Hydrachnidiae)
parasitise aquatic insects and occasionally sponges and molluscs. The larvae of
terrestrial parasitengonids usually parasitise other arthropods and are quite
commonly found in amber attached to a host. Larvae of Trombiculidae (chiggers) typically parasitise vertebrates and can induce lesions in humans with
intense itching. Chiggers are also vectors of diseases such as scrub typhus.
Parasitengona can be traced back to the Cretaceous—specifically the families
Erythraeidae and Tanupodidae. For example the ca. 105 Ma San Just (Spain)
amber includes a larval mites parasitizing a fly (Arillo et al. 2018). The San Just
fossils were assigned to Leptus sp., but may be misidentified and not congeneric (Sidorchuk and Khaustov 2018). The ca. 78 Ma Canadian amber includes
an erythraeid feeding on a midge (Poinar Jr et al. 1997). Numerous examples of
larval parasitengonids attached to insect hosts (Fig. 9.4a, b) have been recorded
in the younger Baltic and Dominican ambers (e.g. Poinar Jr 1985a; Poinar Jr
et al. 1991; Eichmann 2002; Dunlop and Penney 2012).
4. Myobioidea, in the cohort Raphignathina, contains a single family, Myobiidae,
consisting of ectoparasites found in the fur of a variety of marsupial and placental mammals. Their origins may be South American and potentially predate the
marsupial/placental split, which may have occurred in the Jurassic. Fossil of
these mites were recently recognised in Eocene (ca. 44–49 Ma) Baltic amber
(Sidorchuk et al. 2019). The authors found the mites associated with fossil hairs
(Fig. 9.4c) from which they inferred that the host may have belonged to the
extinct Amphilemuridae, the probable sister-family to hedgehogs. There is also
a subfossil record of these mites on a Pleistocene vole (Dubinina and
Bochkov 1996).
5. Pterygosomatoidea, also in Raphignathina, contains a single family,
Pterygosomatidae, which is typically ectoparasitic on lizards and tortoises, and
occasionally also arthropods such as cockroaches. A fossil pterygosomatid was
described from Cretaceous (ca. 100 Ma) Archingeay amber from France by
Sidorchuk and Khaustov (2018). The authors could not match it to a definitive
host, but speculated that it may have lived on the cockroaches that are also
found quite commonly in this amber.
6. Cheyletoidea, also in Raphignathina, is an important assemblage of families, of
which Cheyletidae includes free-living predators, nest-associates and parasites
of arthropods, birds and small mammals. The remaining six cheyletoid families
J. A. Dunlop
Erynetidae feed on the blood of gastropods (snail mites) while others are haematophagous in the nasal cavities of amphibians and birds (André and Fain
2000). The entire superfamily potentially goes back to the Early Devonian
(Dunlop and Garwood 2018) with fossils assigned to Tydeidae, but the
Erynetidae (with parasitic species) lacks a fossil record.
3. Parasitengona is a cohort accommodating a substantial number of species,
including velvet mites, chiggers and water mites. They all share a particular
developmental strategy in which inactive and active juvenile stages alternate
with one another, and in which the larva—which is morphologically quite different from the adult—is active and parasitises invertebrate or vertebrate hosts,
see Wohltmann (2000) for a review. The larvae of water mites (Hydrachnidiae)
parasitise aquatic insects and occasionally sponges and molluscs. The larvae of
terrestrial parasitengonids usually parasitise other arthropods and are quite
commonly found in amber attached to a host. Larvae of Trombiculidae (chiggers) typically parasitise vertebrates and can induce lesions in humans with
intense itching. Chiggers are also vectors of diseases such as scrub typhus.
Parasitengona can be traced back to the Cretaceous—specifically the families
Erythraeidae and Tanupodidae. For example the ca. 105 Ma San Just (Spain)
amber includes a larval mites parasitizing a fly (Arillo et al. 2018). The San Just
fossils were assigned to Leptus sp., but may be misidentified and not congeneric (Sidorchuk and Khaustov 2018). The ca. 78 Ma Canadian amber includes
an erythraeid feeding on a midge (Poinar Jr et al. 1997). Numerous examples of
larval parasitengonids attached to insect hosts (Fig. 9.4a, b) have been recorded
in the younger Baltic and Dominican ambers (e.g. Poinar Jr 1985a; Poinar Jr
et al. 1991; Eichmann 2002; Dunlop and Penney 2012).
4. Myobioidea, in the cohort Raphignathina, contains a single family, Myobiidae,
consisting of ectoparasites found in the fur of a variety of marsupial and placental mammals. Their origins may be South American and potentially predate the
marsupial/placental split, which may have occurred in the Jurassic. Fossil of
these mites were recently recognised in Eocene (ca. 44–49 Ma) Baltic amber
(Sidorchuk et al. 2019). The authors found the mites associated with fossil hairs
(Fig. 9.4c) from which they inferred that the host may have belonged to the
extinct Amphilemuridae, the probable sister-family to hedgehogs. There is also
a subfossil record of these mites on a Pleistocene vole (Dubinina and
Bochkov 1996).
5. Pterygosomatoidea, also in Raphignathina, contains a single family,
Pterygosomatidae, which is typically ectoparasitic on lizards and tortoises, and
occasionally also arthropods such as cockroaches. A fossil pterygosomatid was
described from Cretaceous (ca. 100 Ma) Archingeay amber from France by
Sidorchuk and Khaustov (2018). The authors could not match it to a definitive
host, but speculated that it may have lived on the cockroaches that are also
found quite commonly in this amber.
6. Cheyletoidea, also in Raphignathina, is an important assemblage of families, of
which Cheyletidae includes free-living predators, nest-associates and parasites
of arthropods, birds and small mammals. The remaining six cheyletoid families
J. A. Dunlop