Description of new taxa
Tarachoptera, ordo nov.
Type family: Tarachocelidae fam. nov. (Burmese amber)
Description (Figs. 1–14): Head flat, dorso-ventrally depressed, with coronal,
frontal and frontogenal sulci present, one pair of elongate setose areas on
vertex and frons, ocelli absent; antenna filiform, with barrel-like
flagellomeres; anteclypeolabrum separated by horizontal furrow from
frontoclypeus and kneed in frontal direction; mandibles vestigial; maxillary
palpi very small, three-segmented, galea triangular; labial palpi long, porrect
or ascending, three-segmented; cervix enlarged with laterocervicalia and
additional pair of small cervical sclerites on dorsal side. Thoracal
segments inclined frontad, pronotum flat, divided by membranous, transverse
furrow into an anterior and posterior plate, both connected with
lateropleuron small setose areas on lateral sides of pronotum. Wings
homoneurous, with three radial veins forming a long radial cell closed
apically by crossvein r1–r2; media unbranched, wing surface covered by small
scales, which are spindle-shaped with acute or slightly rounded tips,
hindwing and wing margin scales lanceolate and 2 times longer, but with
only three to four primary ridges; veins devoid of hairs or scales; large and erect
androconial scales on radial and medial veins of male fore- and hindwing
present or absent. Hindwings incompletely covered by scales, smallest scales
with a size of 28–35 µm and more pigmented (darker) than other scales;
all scales on the wings bent and slightly arched, which is in contrast to the
flat scales of Lepidoptera; wing membrane on both wings densely covered by
tubercles, giving the wings a granulate appearance; scales present on
antennae, head, thorax and legs; legs slender, tibia of all legs without
spurs, pretarsus with simple claws and pulvilli. Abdomen of male with
sternal processes on segment IV–VI. Male genitalia small, retracted into
segment IX, and covered dorsally by single, long plate; segment IX with comb
of spines on ventro-caudal margin. Female genitalia with paired or unpaired
dorsal plate.Diagnosis: The characters 21–29 in Figs. 4–9 discussed below are interpreted as
apomorphies of the new order. Seven characters (1, 2, 4, 8, 9, 12, 13) were
identified as amphiesmenopteran apomorphies (see discussion below). Three
apomorphies of the Trichoptera/Lepidoptera clade (3, 6, 14) are in a
plesiomorphic state, with the architecture of the prothorax as the most
remarkable character (see Figs. 2, 9).Tarachocelidae fam. nov.(urn:lsid:zoobank.org:act:8C5E04FF-2B78-4BD4-A55F-2480D4BC90C9)Type genus: Tarachocelis gen. nov.,Description: Head elongate, mouthparts slightly hypognathous, vertex without
setal warts, eyes oval, antenna filiform, maxillary palpi very short,
three-segmented, of equal length, ciliated, last segment pointed; labial
palpi long, three-segmented, all segments of about equal length, with long
hairs, terminal segment with pointed apex; labrum large, produced medially
as a quadroangular and voluminous organ, not set as a prolongation of the
clypeus but protruding by nearly 30∘ from the clypeus; pilifers
absent, pretarsus with slender ungues and stalked arolium, pulvilli absent;
fore- and hindwings of nearly the same length with rounded apices,
pterostigma absent, venation homoneurous concerning branching of R and M
veins, three radial and a single median vein present; small jugum present,
folded under base of wing, forewing with Sc a thin vein branched apically
and with humeral (h) and subapical crossvein sc–r; radius divided into two
thick veins, bearing broad, triangular, putative androconial scales on the
underside of the wing, upper R vein unbranched (R1), lower R vein with two
terminal branches R1 and R2 (or R2+3 and R3+4), ending on wing margin before and at
apex respectively.Tarachocelis gen. nov.(urn:lsid:zoobank.org.act:BDE44937-0710-426A-B2A5-C4850CAFFF6A)
Type species: T. microlepidopterella spec. nov.Gender: Female.Etymology: The name is derived from the Greek ταραχη (tarachi), frightened, staggering, which concerns the presumed flight of the
adults.Description: As described for the family.Diagnosis: Males with presumed androconial scales on R and M veins on the
underside of the forewings and on the upper side of the hindwings. Membrane
of forewing sparsely covered by spindle-shaped and piliform scales without
perforations. Humeral vein in the forewing present and apical section of Cu2
in forewing absent.Tarachocelis microlepidopterella spec. nov.(urn:lsid:zoobank.org:act:2CADD125-72AA-4F9B-81B7-106B980B4C12)(Figs. 13–14)
Material: Holotype male, Burmese amber, S. Anderson Coll. (No. 47), Reg. No.
G2010.20.36, National Museums Scotland, Edinburgh.Etymology: The name refers to the general similarity of the insect to
various microlepidopteran species.Description: Length of forewing 3 mm; length of hindwing 2.9 mm; head
elongate and somewhat flattened dorso-ventrally, scape and pedicel together
as long as eye diameter, scaled dorsally, 23 barrel-shaped flagellomeres
present, basal segments (1–8) with scales, subsequent segments unscaled,
each flagellomere with short cilia, evenly distributed over the entire
length; spurs and smaller spines absent on all tibiae, tarsal segments with
terminal pair of ventral bristles; crossveins cu–r1 and r1–r2+3 present,
the latter closing an elongate, triangular, radial cell; crossvein m–cu1a
present; basal part of Cu2 fused with Cu1a+b; anal veins (A1 and A2)
apparently with basal loop. Hindwing venation similar to forewing venation.Kinitocelis gen. nov. (urn:lsid:zoobank.org:act:22FA942B-37FA-4C47-932B-26519E0393A3)Type species: K. hennigi spec. nov.Gender: Female.Etymology: The name is derived from the Greek kinitos, agile, and
celis, as a suffix of generic names.Description: Small adult insects with 2.3–4.5 mm wing length, and 2.5–4.3 mm body length. Wings held above abdomen in a flat and overlapping mode.
(1–5) Wing venation. (1) Kinitocelis hennigi spec. nov. (B113); RC – radial cell. (2) Kinitocelis divisinotata spec. nov. (B44). (3) Kinitocelis divisinotata spec. nov. (B67). (4) Kinitocelis brevicostata spec. nov. (BUB319).
(5) Kinitocelis brevicostata spec. nov. (BUB399).
Head: Elongate, moderately dorso-ventrally depressed, hypognathous, frons
and vertex with semi-erect scales, eyes hemispherical, ocelli absent,
antenna filiform, 20–26 barrel-shaped, scaled flagellomeres; head capsule
with coronal and frontal sutures, fronto-genal sutures also present,
anterior tentorial pits large, deep furrow between frontoclypeus and
clypeolabrum, proximal part of clypeolabrum sclerotized, distal part
membranous, mandibles vestigial, reduced to small, conical processes, lying
laterally of clypeolabrum and obviously nonfunctional, galea of maxilla an
enlarged, nearly triangular, flat lobe with a blade-like anterior margin,
maxillary and labial palpi three-segmented and scaled, labial palpi much
longer than the former, haustellum or proboscis absent.
Thorax: Thoracal segments inclined towards head, cervix extensible,
laterocervical sclerite from broad base on episternum spanning to hind
margin of head, pronotum seemingly divided transversally into an anterior
and posterior notum, corner of anterior notum connected ventrally with
episternum; fore- and hindwings translucent, of nearly the same length with
rounded apices, humeral vein and pterostigma absent, jugal lobe transformed
into rod-like appendage or absent, venation homoneurous concerning branching
of R and M veins, three radial and a single, unbranched media present,
forewing Sc with or without apical fork (Sc1 and Sc2), bases of R1+2 and
R3 and crossvein r2–r3 forming radial cell (RZ); spindle-shaped scales and
piliform or lanceolate scales on the wing membrane, the scales without
perforations, some scattered scales also on the ventral side, hindwing
scales and fringes mostly of the piliform type, hindwing without jugal lobe,
Cu1b forming a false crossvein between Cu1a and A1, Cu2 absent; legs
slender, epiphysis on foreleg absent, spurs and additional spines absent on
tibiae, basal tarsomere nearly as long as remaining tarsal segments
together, all tarsal segments with apical pair of short spines.
(6–8) Kinitocelis divisinotata spec. nov.: (6) head and pronotum, dorsal; (7) head,
latero-frontal; (8) head, ventro-frontal.
(9–14) Kinitocelis brevicostata spec. nov. (BUB319): (9) head and thorax, dorsal;
(10) head, fronto-lateral; (11) pterothorax, lateral; (12) male abdomen with
genitalia, lateral. Kinitocelis brevicostata spec. nov. (BUB399): (13) head, dorsal; (14) head,
ventral. Kinitocelis divisinotata spec. nov. (BUB730): (15) head, dorsal.
(16–22) Female genitalia. (16–17) Kinitocelis hennigi spec. nov. (B113), lateral (16) and ventral (17). (18–19) Kinitocelis divisinotata spec. nov., lateral (18) and ventral (19). (20) Kinitocelis brevicostata spec. nov.
(BUB399), ventral. (21) Male abdomen of K. brevicostata spec. nov., lateral view (B384). (22) Wing scales, dorsal side of K. brevicostata spec. nov. (BUB 843). Hindwing – A–B: dorsal
side; C: lateral side. Forewing – D–E: dorsal side; F: lateral side.
Abdomen: Female abdomen without sternal processes, male sternum of abdominal
segment V with pair of short, lateral processes, segments VI–VII with
small protuberances in shallow depressions on lateral sides.
Genitalia: Male – dorsal part (uncus?) an elongate, roof-like plate,
ventral part (vinculum?) with a bulbous, distal margin equipped with a
transverse comb of about 15–20 stiff spines, valvae short, in vertical
position, hardly protruding beyond comb of spines.
(23–25) Head in lateral view (without flagellum). (23) Rhyacophila sibirica McLachlan,
1879; (24) Micropterix calthella (Linnaeus, 1758); (25) Kinitocelis brevicostata spec. nov. (BUB
319).
Cladogram of the phylogenetic relationship of Tarachoptera,
Lepidoptera and Trichoptera (numbers correspond with those for
synapomorphies and autapomorphies cited in the text).
Females – dorsal part of final, abdominal segment produced distad with a
pair of oval plates attached to the lateral sides, or with a single,
apically rounded plate; ventral part broadly rounded bearing a large,
triangular process in the middle, or without process, but with notched
ventral margin.Diagnosis. Kinitocelis gen. nov. can be separated from Tarachocelis gen. nov. by characters of wing venation:
the humeral vein is absent, the radial and median veins are without
enlarged, androconial scales and the postcubital vein (Cu2) has lost its
free, apical section. An advanced character is the dense scaling on the
forewings in contrast to the sparsely scaled wings of Tarachocelis.Kinitocelis hennigi spec. nov.(urn:lsid:zoobank.org:act:71B3ADEE-519A-4682-A105-F2180C539195)(Figs. 1, 4(16–17), 8)Material: Holotype , B 113, deposited NIGP 164790Etymology: Named in honor of Willi Hennig (1913–1976), in recognition of his
ideas on the phylogeny of Ampiesmenoptera published in Hennig (1969).Description (holotype): Length of forewing 2.9 mm; length of body 3.0 mm.
Antenna with 21 flagellomeres; in forewing (Fig. 1(1)) subcosta apically
furcate, right wing with a single costal crossvein, which is absent on left
wing, distance between sc–r and r1–r2 is 2 times the length of the latter
crossvein, A1 and A2 looping, jugum in form of a rod-like appendage;
hindwings slightly broader than forewings, crossvein r1–r2 very short.
Female genitalia (Fig. 4(16–17)): Dorsal part of final, abdominal segment
produced distad with a pair of oval plates attached to the lateral sides,
ventral part broadly rounded bearing a large, triangular process in the
middle, directed distad.Diagnosis: The species differs from all other species of the genus by the
presence of an apically forked subcosta and the rod-like jugum of the
forewing. The absence of the costal crossvein in one wing qualifies this
character as regressive and of limited taxonomic significance.Kinitocelis divisonotata spec. nov.(urn:lsid:zoobank.org:act:2DE92E61-C740-414E-8658-9DB441D79C55)(Figs. 1(2–3), 2(6–8), 3(15), 4(18–19), 9)Material: Holotype , B 44x, deposited in NIGP
164789Paratypes: 1 , BUB 773, deposited in PM; 1 , BUB 730, deposited in MfN; 1
, B 67 and 1 , B 390 deposited in NIGP 164785, NIGP 165287Etymology: The specific name refers to the seemingly split prototum in
dorsal view.Description (holotype): Length of forewing 3.5 mm; length of body 3.5 mm.
Antenna with 22 flagellomeres; terminal segment of labial palpi thickened;
pronotum divided into anterior and posterior plates by transverse fold,
anterior plate connected ventrally with episternum; in forewing (Fig. 1(2–3)) subcosta simple, not forked, ending on wing margin before or after
crossvein r1–r2; distance between sc–r and r1–r2 variable, 1 to 4 times
the length of the latter crossvein, A1 and A2 looping, scales sparsely
distributed on wing surface; hindwings as broad as forewings, crossvein
r1–r2 as long as sc–r1.
Female genitalia (Fig. 4(18–19)): Dorsal part of final abdominal segment a
single, elongate, oval plate, ventral part broadly rounded, upturned and
notched in the middle.Diagnosis: The club-shaped labial palpi, the female genitalia and the long
apical section of the subcosta beyond crossvein sc–r are diagnostic for the
species.Remarks: The wing venation appears to be variable in the length of the
radial cell (RZ). The positions of the crossveins are altered adequately. In
Fig. 1(3) the aberrant wing venation of B 67 is depicted. It is left for
future studies and more material to decide whether the forewing venation is
indeed a variable character of K. divisinotata spec. nov. or a second species is involved.Kinitocelis brevicostata spec. nov.(urn:lsid:zoobank.org:act:B7D7B85C-630F-456D-B010-74B5E41DD76D)(Figs. 1(4–5), 3(9–14), 4(20–21), 10–12)Material: Holotype , BUB 399, deposited in MfN;Paratypes: 1 BUB 319 PM, 1 B 307 WW,
1 352 NIGP 164786, 1 , B 371
NIGP 164787, 1 , B 384 NIGP 164788, 1 , BUB 843 PM, deposited NIGP, WW
and PM.Etymology: The specific name is composed of the Latin brevis, short, and
costa, vein referring to the atrophied or weakly sclerotized apex of
subcostal vein.Description (holotype): Length of forewing 4.5 mm; length of body 4.3 mm.
Antenna with 26 flagellomeres, the paratypes with 22–23 flagellomeres; erect
piliform scales on frons arranged in two lines, right mandible a small,
rounded cone sitting in a deep cavity close to the lateral side of
clypeolabrum, segments of labial palpi sparsely scaled; in forewing (Fig. 1(4–5)) subcosta forked, both branches close together and weakly sclerotized,
distance between sc–r and r1–r2 is the length of the latter crossvein, A2
and A3 looping, a small rod-like jugum present, scales densely distributed
on wing surface; hindwings broad as forewings, only on costal area with
dense scaling, crossvein r1–r2 shorter than sc–r1. Male abdomen with
sternites V-VII enlarged dorsally and with a bulbous protuberance displaying
a round orifice in a shallow depression.
Cladogram of Hennig (1969) on the presumed phylogeny of
Amphiesmenoptera, illustrating the topographic differences between genuine
and false (= unechte) stem groups. The cladogram still applies and the
position of Tarachoptera is inserted, demonstrating its early branching from
an amphiesmenopteran ancestor.
Female genitalia (Fig. 4(20)): Dorsal part of abdominal segment with pair of
oval plates, ventral part broadly rounded, upturned and notched in the
middle.
Additional characters provided by paratype specimens BUB 319:Male genitalia (Fig. 3(12)): Dorsal part of abdominal segment IX a flat,
elongate plate with truncate apex, overarching the genital cavity; ventral
part with a short vinculum, and short vertical processes (? valvae); ventral
hind margin of segment VIII with a comb of about 20 stiff spines, directed
distad.Diagnosis: The reduction of the apical section of the subcosta in both veins
is a distinguishing character of the new species. The individuals of this
species are slightly larger than the preceding species. There is some
variation in the wing venation among the specimens, which is probably due to
different embedding positions rendering direct comparisons and productions
of corresponding illustrations difficult to make.
Kinitocelis hennigi spec. nov., holotype (B113): (a) dorso-lateral view and (b)
ventral side of tip of female abdomen.
Discussion
Amphiesmenopteran characters
Kristensen (1984) and Kristensen and Skalski (1998) summarized the
autapomorphic characters of the superorder Amphiesmenoptera. In addition,
Ivanov (2002) mentioned one trait (most of the forewing Sc branches lost)
from his paleontological perspective. The presence of well-developed silk
glands was found to be an embryological autapomorphy (Kobayashi and Ando,
1988). Of the 23 autapomorphies identified at that time (1984–2002), 19 are
adult and 3 are larval characters. Most of them have no relevance in the
study of amber fossils, because they concern embryological, anatomical and
cytological structures unobservable in inclusions. Characters of the exoskeleton can only be used for comparisons if well preserved and not covered by wings or other structures. None of the examined specimens displays the full
set of the critical traits. Characters are well visible in one specimen but
not in the other. The descriptions and discussions are based always on the
individual that shows the character in the clearest way. The following
characters in the sequence and numbering of Kristensen (1984) are applicable
to Tarachoptera:1. Prelabium fused with hypopharynx. This composite structure leads to the formation of the haustellum. The
haustellum of primitive Trichoptera and of the aglossatan Lepidoptera
families (Micropterigidae, Agathiphagidae, Heterobathmiidae) has a similar
structure (see Kristensen and Nielsen, 1979). The fossil specimens do not
show a clear haustellar lobe which allows a direct recognition of this
autapomorphy, but in the holotypes of K. divisinotata spec. nov. and K. brevicostata spec. nov. the
opening of the preoral cavity is visible, situated ventrally of the galea
lobes (Figs. 2(7–8), 3(10, 14)). In extant Trichoptera the preoral cavity
is filled with the eversible haustellum, in which no space is left for a
large opening or a large preoral cavity that can be seen from frontal view.
As a consequence, an assumed haustellum of Tarachoptera must be a small
organ too, similar to that of Micropterigidae. The preoral cavity appears to
be large enough to provide space for something like an infrabuccal pouch in
the hypopharynx, which plays a role in crushing food particles and which was
considered by Kristensen (1984) as plesiomorphic for the Amphiesmenoptera or
Panorpida. However, the vestigial mandibles of Tarachoptera are obviously
not moveable and thus unable to interact with an infrabuccal pouch. This
function of the mandibles could have probably been adopted by the triangular
galeas, which show blade-like ventro-median margins. If this is correct, the
food particles were probably not pollen grains but something of a softer
consistency like sporangia of lichens or fungi.2. Lower posterior corner of laterocervicale produced towards the prosternum. The morphology of this cervical sclerite corresponds largely with the
sclerites in extant Lepidoptera and Trichoptera. The cervix was observed in
two fossil specimens (BUB 730, B 352) as a long, eversible organ with a pair
of additional cervical sclerites or protuberances on the dorsal side (Fig. 3(15)). These sclerites are not known to occur in extant species of
Trichoptera and Lepidoptera, but are present in distantly related orders
like Homoptera, Zoraptera and Mantodea (Matsuda, 1970). The sclerites as
supporting structures probably developed together with the elongated
cervical membrane, which led to a greater movability of the head. The cervix
and its dorsal, cervical sclerites seems to be an adaption to an unknown
foraging behavior and might have evolved independently from other lineages.3. Pronotum with paired setose warts. In contrast to Trichoptera and Lepidoptera, which have vertically
upright standing pronota with the warts in the middle, the pronotum of
Tarachoptera is a flat plate, with setose parts on the lateral sides only,
but without warts or distinct protuberances (Figs. 2(6), 3(9, 15)). In a
number of Trichoptera families (e.g., Philopotamidae, Calocidae) the pronotum
carries two pairs of setose warts, a condition which is considered a
groundplan character of Trichoptera (Ross, 1956). The pronotum in
Tarachoptera is divided into anterior and posterior plates by a membranous
fossa or fold (Fig. 2(6)). The plates can lie in the same plain or are
angled on the transverse membrane. On the lateral sides, the pronotal plates
seem to come close to the anepisternum and epimeron of the propleuron.
Transverse sutures of the pronotum are described from Mecoptera (Matsuda,
1970). In the family Hepialidae (Lepidoptera) the pronotum includes an
anterior dorsal plate (Nielsen and Kristensen, 1989) which could be
interpreted as a remnant of a larger and transversely divided pronotom.
However, the median sulcus of this anterior plate is not present in
Tarachoptera, making homology of both structures doubtful. The morphology
of the pronotum in Tarachoptera differs considerably from
Trichoptera/Lepidoptera and represents very probably the plesiomorphic state
in Amphiesmenoptera, preserved in Tarachoptera.4. Pterothoracic episterna with characteristic suture pattern. The paracoxal sulcus and a short, ventrad running sulcus depicted by
Kristensen (1984) are also present in Tarachoptera.5. Secondary furcal arms in pterothorax fused with posterior margin of corresponding epimera. This autapomorphy becomes visible only by looking at the back sides of
these segments. None of the available specimens allows this observation.6. Metathorax with a setose sclerite in the wing base membrane below/behind the subalare. A setose sclerite is absent in this position, an observation possible
only in specimen BUB 319 of K. brevicostata. However, the subalare in both thoracal
segments is not discernable, but the dorsal side of the epimeron is
unusually large and slightly concave (B 113).7. Pretarsus above the claws with a pseudempodium, a strong seta on a socket. The pseudempodium is not clearly visible. Observing this character is
further complicated by the presence of several setae arising from the dorsal
side of the pretarsus.8. Wings with extensive covering of setae. Setae are present on both the fore- and hindwings. They are dispersed
randomly among the more numerous scales. Like in Lepidoptera and some
Trichoptera the scales on the wings of Tarachoptera are modified setae.
Their dorsal surface has 4–8 primary ridges without providing any visible
perforations between ridges. They are spindle-shaped (like in Neopseustidae)
and occur in different lengths (Fig. 4(22)). The forewing scales are smaller
and more dense than their hindwing counterparts. The latter are somewhat
elongate, with the longest comprising the fringes on the wing termen. The
fringes of the anal hindwing margin are comprised of long hairs.9. Anal veins of the forewings apparently looping up into a double-Y configuration. The anal veins of the forewing are amalgamated, but they differ in the
studied specimens (Fig. 1). Apart from a double-Y form, a simple Y
configuration is the dominant pattern, with or without a short, free apical
piece of A3, which runs to the wing margin.10. One ventral neck muscle originating on the fore coxa; 11. conical furcopleural muscle in the mesothorax with broad end on the pleural ridge. These anatomical characters are not observable in fossils, but could
possibly observed by using micro-CT scans.12. Presence of paired glands opening on sternum V. Dorsal processes on the sternites of the abdominal segments are
interpreted as being the location of gland openings. In Trichoptera similar
sternal processes occur in several primitive families (e.g., Hydrobiosidae,
Polycentropodidae) (Ivanov and Melnitsky, 2002; Djernaes, 2011). However, we
cannot decide from the Tarachoptera fossils which segments are involved
because intersegmental lines or depressions are obscured and a distinction
between membranes and sclerites is not possible. Nevertheless, at least two
segments have sternal processes, which points to the presence of more than
one gland pair (Figs. 3(12), 4(21)). Only the males exhibit these sternal
processes, a situation also found in Lepidoptera, Agathiphagidae (Djernaes
and Kristensen, 2011).13. Male abdominal segment IX with tergum and sternum fused, forming a closed ring. This character is present in the examined male specimens of
Tarachoptera (Fig. 3(12)).14. Anterior margin of female segments VIII and IX with long, rod-like apodemes, accommodating the insertion of protractor/retractor muscles of the extensible oviscapt (= ovipositor). The studied females of Tarachoptera do not possess papillae anales
nor any elongated structures, which would imply the existence of an
ovipositor (Fig. 4(16, 18)). If apodemes are present, they must be small
and not of the long, rod-like shape as in extant Trichoptera and
Lepidoptera. In Trichoptera vestiges of apodemes are retained in several
families (e.g., Philopotamidae, Phryganeidae, Apataniidae), which are reason
enough to consider the lack of these apodemes as secondary losses. This
explanation is probably not applicable to the lacking apodemes in aglossatan
Lepidoptera families (Micropterigidae, Heterobathmiidae) (Kristensen 1998) and in the
primitive Hydrobiosidae of the Trichoptera. However, the ovipositor with
long apodemes on segment VIII and IX is an ancestral character found in
fossil specimens from the Upper Jurassic to Lower Cretaceous and was used to
establish the extinct Lepidoptera family Eolepidopterigidae (Rasnitsyn,
1983).
Kristensen (1984) discussed a further five characters from visceral anatomy
and cytology, including the female heterogamety as the classical
synapomorphy, which are, however, of no relevance here.
The results of the above discussion on the presence/absence of
Amphiesmenopteran autapomorphies in Tarachoptera are summarized in Table 1. The numerals refer to character enumeration in the
text.
Seven characters are identified as being present, which clearly support the
placement of Tarachoptera within the Amphiesmenoptera. Three characters were
found to represent the plesiomorphic state, and two further ones remain unclear. The symplesiomorphies deserve further study, because they
imply an advanced state in Trichoptera and Lepidoptera, and may provide
additional synapomorphies for supporting the Trichoptera–Lepidoptera
sister-group relationship.
Autapomorphies of Amphiesmenoptera
present
absent
undecided
Characters
1, 2, 4, 8, 9, 12, 13
3, 6, 14
5, 7
Kinitocelis divisinotata spec. nov., holotype (B 44): (a) dorsal side of adult, (b)
detail of thorax and head, and (c) detail of head and prothorax, ventrolateral.
Autapomorphies of Lepidoptera
Kobayashi and Ando (1988) found three embryological traits which
corroborate the monophyly of Lepidoptera. Kristensen and Skalski (1998) demonstrated the monophyly of Lepidoptera through a suite of 26
synapomorphies. Most characters are found in adults, and a total of 17
concern the exoskeleton. Three of these characters can also be observed in
Tarachoptera:15. Wings with covering of broad scales. Fore- and hindwings in Tarachoptera bear scales which are sparsely or
densely dispersed in a single layer with only a little overlap. Scales are
also present on the underside of the wings, on the head, antenna, thorax,
and legs. The wing vestiture, however, resembles the Lepidoptera vestiture
only superficially. On closer inspection, the arrangement of scales and
scale shape in Tarachoptera do not correspond with conditions in basal
Lepidoptera (see Fig. 11e), but as demonstrated by Simonsen (2001) the
evolution of wing vestiture is rather complex in basal Lepidoptera.
16. Male gonopod (= valva) primarily undivided. Only the tips of the male valvae are visible, barely
protruding beyond the hind margins of segment IX (Fig. 3(12)). The valves
are likely very small and without any hints of segmentation. This character was
listed by Kristensen (1984) as a possible autapomorphy in contrast to the
two-segmented gonopods of ancestral Trichoptera. In both orders, the
gonopods in the basal lineages are usually large and protruding and serve
as grasping organs. The gonopods in Tarachoptera differ clearly from such a
structure. The assumed undivided gonopods is either a convergence or a
symplesiomorphy at the Amphiesmenoptera level. In any case, the character
does not support a relationship to Lepidoptera and Trichoptera.17. Cerci lacking in both sexes. This regressive character is probably of little significance. In
Trichoptera it is present in female Annulipalpia and Spicipalpia but
missing in almost all families of Integripalpia. The cerci are usually
flanking the anal opening or are placed behind it, lying on a membranous
short or telescoping segment X (ovipositor). A membranous terminal segment
or ovipositor is not visible in Tarachoptera, and probably not present (Fig. 4(16, 17)). Even in a retracted position deep inside the genital–anal
cavity of the abdomen, the tips of the papillae anales should be discernable
at least.
In summary, we did not find any characters that support a sister-group
relationship between Tarachoptera and Lepidoptera. The presence of wing
scales is a shared character, but their different morphology suggests a
different origin and makes it unlikely to assume common ancestry. A
predisposition for the development of scales could be thought or held for
the presence of an intrinsic trait in ancestral Amphiesmenoptera. The
occurrence of wing scales in derived taxa of Trichoptera, unrelated to that
of Lepidoptera, can be regarded as evidence of this predisposition.
Kinitocelis brevicostata spec. nov., holotype (BUB399): (a) ventral view of adult, (b)
ventral side of tip of female abdomen, and (c) head, ventral side.
Autapomorphies of Trichoptera
Arguments for the monophyly of Trichoptera were first summarized by Ross
(1956: 9), who provided nine adult characters. Weaver (1984) and Morse (1997:
434) added five further homologues supporting monophyly for Trichoptera.
Kobayashi and Ando (1988) provided four embryological characters. Three
morphological characters are applicable to Tarachoptera or deserve some
notes:
18. Modified haustellum. The haustellum of Trichoptera is one of the main apomorphies of the
order. It is a membranous, flexible organ, with a specialized fine structure
on its surface that facilitates the uptake of fluid substances or small
particles. In basal families the haustellum is small, with somewhat enlarged
lateral sides (Klemm, 1966; Kubiak et al., 2015), whereas in families of
Integripalpia the haustellum is a large, bulbous organ resembling a short
proboscis. As already mentioned in the discussion on character 1, a clearly
developed haustellum is not discernible in Tarachoptera. It is probably in a
primitive state, small and not visible externally, a situation also found in
the non-glossatan Lepidoptera.19. Absence of adult mandibular articulations. Sclerotized and functional mandibles are plesiomorphic groundplan
characters of Ampiesmenoptera. They are retained in primitive Lepidoptera
and have well-developed articulations with the head capsule. The mandibles
of Trichoptera are non-functional (Klemm, 1966) and exhibit an array of
different stages of reduction spanning from fully sclerotized ones lying
beneath the anteclypeolabrum to small membranous lobes. The mandibles of
Tarachoptera are also reduced; however, this reduction is more advanced and
the remains of the mandibles appear as conical stumps in grooves beside the
labrum (Fig. 3(14)).20. Nygma. The presence of a single nygma (= corneus spot) in the base of apical
cell 3 or fork 2 in the forewings is regarded a trichopteran synapomorphy.
According to Kristensen (1984) nygmata occur in other holometabolan orders
too, which makes this structure a plesiomorphy at the amphiesmenopteran
level. The autapomorphic nature of the nygma in Trichoptera is the reduction
from several to only one or two (e.g., Calamoceratidae). All examined
specimens of Tarachoptera are without a nygma in the forewings.
There is no single autapomorphy which could serve as an argument for shifting
the Tarachoptera into a closer relationship with Trichoptera. All shared
characters are symplesiomorphies inherited from amphiesmenopteran ancestors.
Kinitocelis brevicostata spec. nov., paratype, (BUB 307): (a) dorso-lateral view of
adult, (b) abdominal tip with comb of spines, ventro-lateral, (c) male
adult in dorsal view (B 384), and (d) same specimen, abdominal tip, ventral
view. (e) Kinitocelis divisinotata spec. nov., paratype (B67), scales on hindwing.
Apomorphies of Tarachoptera, new order
21. Dorso-ventral depression of the head capsule. All insect orders can usually be defined by characteristic head
morphology in combination with the architecture of the mouth parts. In Fig. 5(23–25) the heads of the two basalmost families of Trichoptera
(Rhyacophilidae) and Lepidoptera (Micropterigidae) are depicted and grouped
together with the head of Tarachoptera. (BUB 319). The most striking
features are the compound eyes, which are comparatively large and oval,
resulting probably from the flattening of the head capsule. The vertex is
likewise a flat plate with a pair of elongate setal warts. The frons is also
flat, not protruding, and the mouthparts are situated more basad which gives
the head a pronounced, hypognathous appearance. This configuration of the
head capsule differs strongly from the heads of basal Trichoptera and
Lepidoptera, and differs also from the head morphology of other
holometabolous orders. The dorso-ventrally flattened head with oval eyes is
here interpreted as an apomorphy of the Tarachoptera.22. Ocelli absent. This is a regressive character which cannot easily be ascribed to the
groundplan of Tarachoptera. The groundplan of Lepidoptera is without the
single, frontal ocellus, and in Trichoptera three large ocelli are present.
In many primitive and derived families of both orders the ocelli are reduced
in size and can be completely absent.23. Angled position of the anteclypeolabrum. The anteclypeolabrum with a sclerotized proximal and membranous apical
part present in most Trichoptera (Kubiak et al., 2015) is also present in
Tarachoptera and Lepidoptera. However, at the horizontal furrow between
frontopostclypeus and anteclypeolabrum, the latter is bent frontad nearly at
a right angle forming a protruding, thick process (Fig. 5(25)). In basal
Lepidoptera and Trichoptera the clypeus and labrum are not angled here, and
the labrum is a simple linear prolongation of the frons.24. Triangular galea. The basal sclerites of the maxilla are not visible. The distal parts
consist of the three-segmented maxillary palpi and a triangular lobe, which is
here interpreted as the galea (= outer endite). The inner endite of the stipes, the
lacinia, is not visible. In Trichoptera both endites can form a composite structure
(the galeolacinia of Kubiak et al., 2015). The galea is a flat plate of
triangular shape and seems to have a thin, blade-like anterior margin. It is
regarded as autapomorphy of the Tarachoptera.25. Maxillary palpi reduced. Maxillary palpi with five segments and being much longer than the labial
palpi with three segments are the ancestral character state in Trichoptera and
Lepidoptera (Fig. 5(23–25)). It is retained at least in the females of
Trichoptera and in the basal families of Lepidoptera. In advanced families
of this order the maxillary palpi are gradually reduced from five, long
segments to a complete absence while simultaneously the labial palpi become
larger and more prominent, leading to a similar configuration to
Tarachoptera palpi. This character, the form of the palpi, has evolved
independently in Exoporia and in monotrysian heteroneuran families like
Prodoxidae and Palaephatidae (Lepidoptera), but here the lepidopteran proboscis
was already in existence (Davis, 1986, 1998), and the reduction of the
maxillary palpi seems to be a convergence which must have occurred several
times.26. Elongate cervix with dorsal sclerites. Usually, the membrane between head and prothorax is short and
stabilized by the laterocervicalia. In Tarachoptera the cervix is longer and
has developed an additional pair of dorsal sclerites, which are hitherto not
observed in Lepidoptera/Trichoptera (see character 2).27. Tibial spurs absent on all legs. This strange character is known from specialized species in Psychidae
and in Hepialidae (Lepidoptera), but as far as we know it is not described from a
Trichoptera taxon. The existence of spurs is a plesiomorphy of the
Holometabola and certainly belongs to the groundplan of Amphiesmenoptera.
Its complete absence in Tarachoptera is rather unusual and raises questions
about the function and adaptive value of spurs in insects. According to
Burrows and Dorosenko (2015) spurs are involved in the jumping abilities of
adult insects, which do not possess a catapulting mechanism. Jumping is not
only a process of rapid movements to escape predators or to bridge space
but is also involved in the start of flight. Spurs are needed to enable
rapid movements of both the middle and hind legs, providing propulsion that
launches winged adult moths into the air. The absence of spurs in
combination with a weak wing coupling mechanism appears to be a strong
argument for the assumption of a restricted flight ability of the
Tarachoptera species.28. Radial system of both wings with three branches forming a radial cell. This is a unique character in the wing venation which does not occur
in extant Trichoptera/Lepidoptera. In checking the huge record of
illustrations of fossil wings (e.g., Handlirsch, 1906; Kozlov, 1988;
Kuznetsov,
1941; Rodendorf, 1962; Tindale, 1980) not a single species was found with
radial veins reduced to three branches in the fore- or hindwings. Also, the
unbranched media is a further apomorphic trait which contributes to the
strange and unique wing venation of Tarachoptera. In Lepidoptera, a simple,
undivided medial vein was observed only in the primitive family
Aenigmatineidae (Kristensen et al., 2014).29. Wing scales. The scales of primitive Lepidoptera are mostly of the solid type,
i.e.,
without a lumen and perforations, a type 1 bilayer scale covering and
primary ridges extending beyond apical scale margin (Simonsen, 2001). The
scales of Tarachoptera are also without perforations, but somewhat smaller
with smooth apical margins. All scales on wing surface are bent and slightly
arched with the concave side facing wing membrane (Figs. 5(25), 11). The
scales are of a single type and are arranged in a single layer with little
overlapping.
Kinitocelis brevicostata spec. nov., paratype (BUB319): (a) ventro-lateral view of adult,
(b) head and thorax, dorsal, and (c) abdominal tip and hind tarsus,
ventro-lateral view.
The different morphology and arrangement of the Tarachoptera scales is no
evidence of a different origin but suggests a different development which
does not indicate a close relationship to Lepidoptera. The scales have
obviously evolved independently in the two orders from an amphiesmenopteran
ancestor with hairs or setae present on the wings. In Trichoptera scales on
the forewings are observed in several genera of more derived families (e.g.,
Lepidostomatidae, Calocidae, Leptoceridae). Scale-like hairs may also occur
on maxillary palpi, the head or the thorax, but usually in small arrangements or as
singletons. In contrast to Lepidoptera scales the longitudinal ridges of
caddisfly scales lack flutes. It therefore seems likely that scales have
arisen independently in these two orders (Huxley and Barnard, 1988: 310).
The basalmost families of Trichoptera (Spicipalpia) do not have proper
scales on the wing membrane, not exceeding minute scales in the form of
androconinal organs or thickened hairs present in species of Hydroptilidae
and Glossosomatidae.
There are some further characters which seem to be promising candidates for
adding to the list of apomorphies, e.g., the tegulae, the jugum on the
forewings, the female and male genitalia and the pleuronota of the
pterothorax. The detailed observation of these characters is obscured by
position and preservation of the insect within the inclusions available for
study at the moment. The morphology of the first and second abdominal
segments should also bear valuable traits for phylogenetic considerations.
This character complex is regrettably unobservable in all examined
specimens. Future investigations employing micro-CT imagery might provide
more insights whether these characters may serve as autapomorphies.
Phylogeny of Tarachoptera
The Tarachoptera is the first group of fossil Amphiesmenoptera for which we
have a more comprehensive set of data compared to other fossil taxa where
just wings are available. The external morphology of head, thorax and
abdomen could be studied in detail, of course with the restrictions
inclusions in amber usually provide. The fossils were compared with extant
species of Trichoptera and Lepidoptera. We have excluded from the analysis
the extinct taxa such as Protomeropina and Prorhyacophilidae because they
provide with the wing venation only a single character type which is
uninformative at this taxonomic level (see discussion above). Their
inclusion would weaken the strength of the cladogram by the inadequate or
unbalanced number of compared characters.
The monophyly of the order is based on the presence of nine derived characters
of the adult stage (21–29). Most of these characters are of a regressive
nature (22, 25, 27–28) or can be regarded as adaptations to foraging behavior
of the adults (21, 23–24, 26). This array of characters is typical for taxa
which are highly specialized and adapted to peculiar habitats. There are
numerous examples in Trichoptera and Lepidoptera of aberrant species with
many derived characters which render the systematic/phylogenetic placement
difficult. We have the impression that the species of Tarachoptera follow
this pattern qualifying the whole order as a very specialized lineage which
evolved from an amphiesmenopteran ancestor independently from the stem-group
ancestor of the Trichoptera/Lepidoptera clade (Fig. 6). The age of the
Tarachoptera fossils in Burmese amber is about 100 Ma (Ross et al., 2010).
Burmese amber is known to contain species of Micropterigidae and glossatan
moths (Lepidoptera) (Cockerell, 1919; Grimaldi and Engel, 2005; Ross et al.,
2010) and Trichoptera of the families Hydroptilidae, Philopotamidae,
Polycentropodidae, Psychomyiidae and Odontoceridae (Botosaneanu, 1981;
Wichard and Poinar, 2005; Wichard et al., 2011; Wichard and Wang, 2016a,
b). These families take a basal position in the phylogeny of the order
(Holzenthal et al., 2007) (Concerning the glossatan moths of Lepidoptera we
are unable to assign any of the Burmese fossils we have seen to an extant
family). As contemporaries of the same geographical area they appear to
stand in strong contrast to the very advanced species of Tarachoptera. This
led us to conclude that the group had already undergone a long time of
evolution from an ancestor which lived in the Jurassic, probably even
earlier.
The phylogenetic sequence for the three orders of Amphiesmenoptera in the
cladogram in Fig. 6 has been arranged according to the synapomorphic
characters discussed and enumerated in the text. Tarachoptera is obviously
neither an early offshoot of the Lepidoptera branch nor a lineage of the
stem group of Trichoptera. It is probably the first genuine taxon of a number
of amphiesmenopteran clades which are known by fossil wings only (included
in Protomeropina). The Tarachoptera very probably represents an evolutionary
line which branched off from the lineage of the Trichoptera/Lepidoptera
ancestor long before the split into the two extant orders had occurred. The
two genera of Tarachoptera, Tarachocelis gen. nov. and Kinitocelis gen. nov., appear to be crown
groups of this order that have achieved a high level of morphological
specialization in the adult stage, which is probably a reflection of an
adaption to a particular habitat or environment. The Tarachoptera obviously
went extinct. Their specialization was probably one of the reasons for its
disappearance, though we do not know the habits and morphology of the
larvae. The concurrently living species of Micropterigidae with their
completely scaled wings were detritus (larvae) and pollen feeders (adults)
using functional mandibles. This primitive feeding type survived and thereby
conserved the scaly vestiture of body and wings, which became the prominent
morphological character in the later radiation of the Lepidoptera. The
scales of Tarachoptera obviously developed before the scales of the
Lepidoptera were “invented”. It is like a blueprint of a character which
developed its high adaptive value and significance during the evolution and
subsequent radiation of the Lepidoptera, one of the most successful insect
orders in terms of species numbers and ecological adaptations in all biomes
of the globe.
The fossil record
The fossil record of Trichoptera and Lepidoptera differs fundamentally.
Nearly all fossils of the Amphiesmenoptera, prior to the basal split into
Trichoptera and Lepidoptera, were assigned to Trichoptera (Rasnitsyn and
Quicke, 2002; Sohn et al., 2012). The extinct taxa were summarized in the
suborders Protomeropina and Paratrichoptera and in the families Necrotauliidae
Handlirsch, 1906 and Prorhyacophilidae Rieck, 1955. They were not
established as monophyletic entities and represent paraphyletic assemblages
(Schlüter, 1997) which are not included in the global treatment of
Trichoptera (Holzenthal et al., 2011). Most of them belong to lineages of the
stem group of Amphiesmenoptera and only a few may be considered as stem-group
members of Trichoptera. The Trichoptera contain seven extinct families which are
assigned to inclusive taxa of existing suborders or superfamilies. There are
no fossil families in the ancestral Rhyacophiloidea, Hydroptiloidea and
Glossosomatoidea. All fossils associated with Trichoptera have a wing
venation with four to five radial and at least three medial veins. The basal cell
(= discoidal cell, DZ) is enclosed by veins of the radial sector (R2+3
and R4+5) and closed apically by r3–r4. These venation features are in
striking contrast to Tarachoptera, whose species have only three radial and one
medial cell in both wings. The anterior and posterior margin of the basal
cell (= radial cell, RZ) is formed by R1 and R3 and closed anteriorly by
r1–r2. The peculiar venation of Tarachoptera is an autapomorphy of the order
and appears to be a highly derived character, which was already present in
the Cretaceous, at a time when all Trichoptera and most Lepidoptera fossils
had a wing venation similar to Micropterigidae.
In addition to the occurrence of an epiphysis on the fore-tibia, the
recognition of fossil Lepidoptera depends on the presence of wing scales. It
is the most conspicuous and diagnostic groundplan autapomorphy currently
recognized for the Lepidoptera (Kristensen and Skalski, 1998). All fossil
families were assigned to the stem group of Lepidoptera with Archaeolepidae,
Eolepidopterigidae, Mesokristenseniidae and Ascololepidopterigidae described
from the Mesozoic (Zhang et al., 2013). For the Eolepidopterigidae the
suborder Eolepidopterigina was established (Rasnitsyn, 1983). As discussed
above for the Trichoptera, the wing venation bears no resemblance to
Tarachoptera, and wings of fossil Lepidoptera are nearly indistinguishable
from Trichoptera (Kristensen, 1984). With the discovery of the scale bearing
Tarachocelidae fam. nov., the only family of Tarachoptera, we have to
concede that wing scales did not appear for the first time with the advent
of the Lepidoptera but have evolved independently in earlier lineages
within Amphiesmenoptera.
Tarachocelis microlepidopterella spec. nov., holotype, , lateral view.
Aspects of the life history of Tarachoptera derived from morphological
traits
In general habitus the species of Tarachoptera bear an external resemblance
to members of the Trichoptera family Hydroptilidae and Lepidoptera families
Heterobathmiidae and Acanthopteroctetidae. These families belong to the
ancestral or primitive taxa in each order (Holzenthal et al.,
2011; Regier et al., 2015). All species of these families have small to
minute adults and are usually without striking wing patterns or colorful
markings. The presence of small-sized adults seems to be a shared feature in
the evolution and early radiation of both orders. The species of
Tarachoptera are also tiny insects. An advantage of being small is the use
and occupation of a wide array of microhabitats in a small area. In
Lepidoptera the larvae of the smallest species are endophagous and live as
leaf, stem, bark, or seed miners. In Trichoptera, the larvae of
Hydroptilidae are algal feeders in lenitic and lotic aquatic environments.
The females dive into the water in search of oviposition sites. The hairy
surface prevents the wings from becoming wet and enables the females to
display repetitive diving and flying unless a suitable place is found
(Siltalai, 1906: 28). Scaled wings are certainly not an adaptation to an
aquatic environment in general. In assuming that wing scales are a
morphological feature and adaptation of a terrestrial lifestyle, the
Tarachoptera were probably also terrestrial insects. The small size of the
imagines is suggestive for assuming that their larvae were endophagous.
Leaf mining of larvae is an ancient feeding type documented from compression
fossils from the Upper Jurassic and Cretaceous to Oligocene. Leaf mines of
the gallery type were found in fossil leaves of several plant families, and
were assigned to Lepidoptera families Nepticulidae, Bucculatricidae, and
Gracillariidae (Labandeira et al., 1994; Rozefelds, 1988; Opler, 1982). The
association with these families is more or less tentative and, in essence, an
extrapolation from present-day mine morphology of known host and
mining species. We will probably never know the mines of Tarachoptera
species, if they were indeed miners. But the existence of this group in the
Cretaceous provides a new candidate among mine producers, which further
undermines the validity of identification of fossil mines.
Life reconstruction of males of Tarachocelis microlepidopterella spec. nov. performing actions to
attract a female or to push away competing males (illustration by O. Thie).
The adult morphology of the studied species of Tarachoptera provides some
interesting characters, which might be adaptations to a special lifestyle.
The dorso-ventrally depressed head in combination with the probably flatly
appressed wings in their resting position suggests a dwelling of the
imagines in narrow shelters like crevices, fissures, cracks in bark or in
curled leaves. Judging from the mouthparts, the species were not predators
but phytophagous insects. External feeding on plant material can be
excluded because the adults do not have functional mandibles and are
incapable of biting and chewing. With regard to the small size of the
species the food material must have been in the form of small particles or
fluid substances. In the inclusion BUB 319 the labial palpi are holding a
small, rounded particle which was perhaps cracked by the pressure of the
labial palpi. If this is not an artifact, the particle is of particular
interest. Unfortunately, the margins are smooth and the surface does not
offer any microstructures. The question regarding the kind of food remains
unanswered, but the position of the labial palps holding the small grain is
an indication of highly mobile labial palpi and their possible function in
the uptake of food. In the Micropterigidae, the adults feed on pollen
grains, which are gathered by the grasping action of the maxillary palpi and
transported by the galeae into the preoral cavity and hypopharynx, where
they are crushed by the movements of the mandibles (Hannemann, 1956). In
Tarachoptera a similar combined action between labial palps and the galea
pair seems to be a possible mechanism for the uptake of food.
The absence of spurs on the tibia of all legs is an autapomorphy of the
Tarachoptera (see discussion of character 27). Without spurs the insects
were probably not able to perform rapid jumps. However, the presumed habit of the
adults, described above, does not necessitate jumping abilities.
Moreover, as sedentary dwellers in these microhabitats the inclination to
fly should have been reduced.
The presence of enlarged, androconial scales (Fig. 13) on fore- and hindwing
veins in Tarachocelis microlepidopterella spec. nov. opens another aspect in the life history of the new
order. The scales were probably connected with glandular cells aggregated
along the veins. Males release scent or pheromones when the females are
nearby to stimulate the females for mating. Since the sex scales are on the
underside of the forewings and upper sides on the hindwings, the display of
these organs and dissemination of scent should have been performed during a
specific courtship ritual. The release of scent probably happened on an
exposed or otherwise suitable place and attracted females and males. Like at
a tournament ground, the males were competing with each other for females in
a certain courtship ritual. The life reconstruction in Fig. 14 illustrates
such an aggregation of males of T. microlepidopterella spec. nov.