402
Liposcelididae is the sister-group to the parasitic lice clade of Phthiraptera, consisting of the Amblycera + [Anoplura + (Rhyncophthirina + Ischnocera)] clade, equivalent to the common names of chewing lice 1 + [sucking lice + (chewing lice
2 + elephant/warthog lice)], treated separately below. In particular, the Liposcelididae
provides significant clues to the origin of parasitism in the Phthiraptera and provides
evidence that demonstrates tendencies toward parasitism in certain psocopteran
lineages.
Liposcelididae consist of 9 genera and approximately 200 species of small, pale,
dorsoventrally compressed, and often wingless barklice that are inquilines of insect
nests (Mockford 1971). In particular, Liposcelididae are morphologically and
behaviorally intermediate between free-living Pachytroctidae (thick book lice),
from which they originated, and the ectoparasitic Phthiraptera (parasitic lice) clade
with which they are sister groups (Johnson et al. 2004, 2018). Notably, the diet of
probably the best-studied extant booklouse, synanthropic Liposcelis bostrychophila, consists of raw cereal grains treated with yeast (Green and Turner 2005). Other
species of the genus evidently consume sloughed off integument such as flakes of
skin and covering sheaths of feathers (Lin et al. 2004; Grimaldi and Engel 2005b).
Fossils of Liposcelididae are rare, but the lineage has its earliest occurrence in
Myanmar Amber (99 Ma), providing a minimal date for the divergence of
Liposcelididae and Phthiraptera (Grimaldi and Engel 2005b). Nonetheless, a dated
molecular phylogenetic analysis indicates an older separation date at the Triassic–
Jurassic boundary (Johnson et al. 2018).
11.5.1.4 Phthiraptera (Parasitic Lice)
Phthiraptera (parasitic lice) consist of 4 suborders, 24 families, 304 genera and 5316
species that are obligate ectoparasites of birds and mammals (Galloway 2018).
Phthirapterans are wingless, dorsoventrally flattened, have small eyes or are blind,
and possess a variety of sense organs located especially on their antennae and
mouthparts for detection of and their positioning on their hosts (Marshall 1981;
Clayton et al. 2016). As ectoparasites, they complete all life stages of their development on the bodies of their hosts, requiring their host’s moist, warm skin and adjacent humid microenvironment to live and reproduce by attaching their elongate eggs
to hair shafts with a cementing substance (Fig. 11.1k). Lice are sensitive to minute
temperature gradients across their host’s body and die if deprived of their thermally
constrained integumental microenvironment for more than several hours to a few
days (Tompkins and Clayton 1999).
The major clades of the monophyletic Phthiraptera are the Amblycera and the Ish
nocera + (Rhyncophthirina + Anoplura) clades (Johnson et al. 2018). In common
parlance these clades are equivalent to, respectively, the chewing lice 1 clade and
the chewing lice 2 + (elephant/warthog lice + sucking lice) clade. Phthiraptera were
derived from the psocopteran lineage Liposcelididae, with which it shares a sistergroup relationship (Grimaldi and Engel 2005b; Johnson et al. 2018). Within
Phthiraptera, the basal-most lineage is Amblycera, the chewing lice 1 clade. These
C. C. Labandeira and L. Li
Liposcelididae is the sister-group to the parasitic lice clade of Phthiraptera, consisting of the Amblycera + [Anoplura + (Rhyncophthirina + Ischnocera)] clade, equivalent to the common names of chewing lice 1 + [sucking lice + (chewing lice
2 + elephant/warthog lice)], treated separately below. In particular, the Liposcelididae
provides significant clues to the origin of parasitism in the Phthiraptera and provides
evidence that demonstrates tendencies toward parasitism in certain psocopteran
lineages.
Liposcelididae consist of 9 genera and approximately 200 species of small, pale,
dorsoventrally compressed, and often wingless barklice that are inquilines of insect
nests (Mockford 1971). In particular, Liposcelididae are morphologically and
behaviorally intermediate between free-living Pachytroctidae (thick book lice),
from which they originated, and the ectoparasitic Phthiraptera (parasitic lice) clade
with which they are sister groups (Johnson et al. 2004, 2018). Notably, the diet of
probably the best-studied extant booklouse, synanthropic Liposcelis bostrychophila, consists of raw cereal grains treated with yeast (Green and Turner 2005). Other
species of the genus evidently consume sloughed off integument such as flakes of
skin and covering sheaths of feathers (Lin et al. 2004; Grimaldi and Engel 2005b).
Fossils of Liposcelididae are rare, but the lineage has its earliest occurrence in
Myanmar Amber (99 Ma), providing a minimal date for the divergence of
Liposcelididae and Phthiraptera (Grimaldi and Engel 2005b). Nonetheless, a dated
molecular phylogenetic analysis indicates an older separation date at the Triassic–
Jurassic boundary (Johnson et al. 2018).
11.5.1.4 Phthiraptera (Parasitic Lice)
Phthiraptera (parasitic lice) consist of 4 suborders, 24 families, 304 genera and 5316
species that are obligate ectoparasites of birds and mammals (Galloway 2018).
Phthirapterans are wingless, dorsoventrally flattened, have small eyes or are blind,
and possess a variety of sense organs located especially on their antennae and
mouthparts for detection of and their positioning on their hosts (Marshall 1981;
Clayton et al. 2016). As ectoparasites, they complete all life stages of their development on the bodies of their hosts, requiring their host’s moist, warm skin and adjacent humid microenvironment to live and reproduce by attaching their elongate eggs
to hair shafts with a cementing substance (Fig. 11.1k). Lice are sensitive to minute
temperature gradients across their host’s body and die if deprived of their thermally
constrained integumental microenvironment for more than several hours to a few
days (Tompkins and Clayton 1999).
The major clades of the monophyletic Phthiraptera are the Amblycera and the Ish
nocera + (Rhyncophthirina + Anoplura) clades (Johnson et al. 2018). In common
parlance these clades are equivalent to, respectively, the chewing lice 1 clade and
the chewing lice 2 + (elephant/warthog lice + sucking lice) clade. Phthiraptera were
derived from the psocopteran lineage Liposcelididae, with which it shares a sistergroup relationship (Grimaldi and Engel 2005b; Johnson et al. 2018). Within
Phthiraptera, the basal-most lineage is Amblycera, the chewing lice 1 clade. These
C. C. Labandeira and L. Li