Male-specimen deposited Zoological Research Museum Alexander Koenig, Bonn, Germany, Inventory no.: ZFMK-TRI000835 (ex coll. Patrick Müller)

The fossil male is well preserved in amber. Antennae present, as well as the six-segmented maxillary palps. The labial palps are not recognizable. The forewings show the venation well, the hind wings are unfortunately hidden. The inferior appendages of the male genital are visible from ventral.

The extinct Paduniella species is named after its geological age of the Cretaceous period (latin: Cretaceum).

Male, forewings ca. 2.8 mm long, antennae about half as long as forewing. Maxillary palps each six-segmented (Fig. 2C); labial palps not visible. Each forewing has forks II, III, IV, and V; hindwings not visible. In ventral view (Fig. 2B), male genitalia have deep, bifurcated inferior processes each with an elongate, overhanging process that is tapered and slightly curved apically. In lateral view (Fig. 2D), a slender median process is visible.

Figure 2. 

Paduniella cretacea sp. nov. in mid-Cretaceous Burmese amber, male holotype (Inventory no.: ZFMK-TRI0008359. A. Male in ventral view; B. Paired bifurcated inferior appendages in ventral view; C. Paired 6-segmented maxillary palps; D. Drawing of bifurcated inferior appendages (inf app) and median process (med pro) in lateral view.

The male genitalia of Paduniella species have inferior appendages whose apices are either bifurcated or unbifurcated (Li and Morse 1997). The extinct Paduniella cretacea sp. nov. has similar to the extant species, P. tanidai from Japan (Nishimoto, 2011) and P. burmana (Johanson & Olah, 2010) from the Oriental region, bifurcated inferior appendages that are deeply incised at the apex rather than superficially notched. The fossil species is distinguished from the two extant species in the deeply bifurcated apex of the inferior appendage because one fork is needle-like, acuminate, and curved and clearly protrudes above the other stouter fork. Paduniella cretacea sp. nov. is the first fossil Paduniella species found in ca. 100 million year old mid-Cretaceous Burmese amber.

Palerasnitsynus Wichard, Ross & Ross, 2011.

The species of the extinct subfamily Palerasnitsyninae are characterised by the combination of the fore and hind wings’ characters: in forewings by the presence of forks II, IV, V and by the absence of forks I and III and in hind wings by the presence of forks II and V and by the absence of the forks I, III, IV (Fig. 3B). Furthermore, the adults possess latero-apical dark sporns at the 3^rd maxillary palp segments (Fig. 3A).

Figure 3. 

Genus Palerasnitsynus in mid–Cretaceous Burmese amber. A. Typical dark sporns at the 3^rd maxillary palp segment; B. Typical presence of forks II, IV, V in forewings and of forks II and V in hind wings; C. Palerasnitsynus swarming activities.

The extinct genus Palerasnitsynus, with currently 10 species, was found in the Oriental mid-Cretaceous Burmese amber and initially placed in the family Psychomyiidae (Wichard et al. 2011). The wing venation is remarkably reduced, with only apical forks II, IV, V in forewings and apical forks II and V in hind wings. The reduction of forewing venations with the absence of forks I and III and of hind wing venations with the absence of forks I, III and IV is observed in some Xiphocentronids, but not in the family Psychomyiidae. This combination of reduced forewings and hindwings is significantly true for the family Xiphocentronidae. Based on these characters, it is proposed to transfer the genus Palerasnitsynus to family Xiphocentronidae and to establish an extinct subfamily Palerasnitsyninae stat. nov. Its species are the oldest Xiphocentronids with a geological age of about 100 million years.

In Burmese amber, the species of the subfamily Palerasnitsyninae are certainly among the smallest caddisflies, reaching forewing lengths of only 1.8–2.6 mm (Wichard et al. 2011, 2018b). With an abundance of almost 40% of caddisflies, Palerasnitsynus species dominate the picture of caddisflies in the Burmese amber. They obviously have a tendency to swarm, as up to 100 embedded individuals have been counted in some ambers (Fig. 3C).

Palerasnitsynus ohlhoffi Wichard, Ross & Ross, 2011.

The extinct genus Palerasnitsynus is characterised by the combination of the fore and hind wings’ characters: in forewings by the presence of forks II, IV, V and by the absence of forks I and III and in hind wings by the presence of forks II and V and by the absence of the forks I, III, IV (Fig. 3B). Furthermore the adults possess latero-apical dark sporns at the 3^rd maxillary palp segments (Fig. 3A).

A small Burmese amber contains three males, which are the holotype and two paratypes attesting to the new species. The amber is deposited Zoological Research Museum Alexander Koenig, Bonn, Germany, inventory no.: ZFMK-TRI000836 (BUB 3585 ex coll. Patrick Müller).

Two males, preserved in varying condition, are embedded in a single amber (Fig. 4A). The holotype is completely preserved, from dorsal and ventral view. From ventral the pair of the genital inferior appendages is clearly visible. The paratype shows the genital laterally, although not absolutely clear. Forewings and hind wings are spread apart in the paratype.

Figure 4. 

Palerasnitsynus vilarinoi sp. nov. in mid–Cretaceous Burmese amber (inventory no.: ZFMK-TRI000836). A. Holotype (left) and paratype (right); B. Holotype inferior appendages in ventral view; C. Paratype male genitalia in lateral view.

The new species is dedicated to Albane Vilarino, Brasil, who pointed out that the extinct genus Palerasnitsynus may belong to the family Xiphocentronidae.

Male, adult with general characters of the genus, forewing length ca. 2 mm, antennae with about 20 cylindrical flagellomeres, plus scapus and pedicellus.

Genitalia: In ventral view (Fig. 4B), the inferior appendages are almost parallel, the separation of the basal coxopodite and the attached harpago is only weakly indicated, possibly they are fused. The inside flanks of the inferior appendage are loosely equipped with long and strong setae. The basal coxopodite is somewhat elongated and baso-laterally rounded, the harpago probably only slightly longer than the coxopodite. The apex of each harpago bears a dark spiny head with densified spines of nearly equal length. The needled heads of the adjacent harpagoes face each other (Fig. 4B). In lateral view (Fig. 4C), the male genital shows a pair of parallel intermediate processes (int pro) which in length barely reach the level of the medio-lateral process (med pro) which originated from the coxopodite is elongate-round and bears a bush of long setae. The intermediate process is needle-shaped, somewhat broadened in the middle, and tapers toward the apex to a ventrally inclined dark tip. The pair of short preanal appendages and a short needle-like process with dark tip, dorsally inclined, are not clearly visible.

Palerasnitsynus vilarinoi sp. nov. is exclusively characterized by the latero-apical dark sporns at the 3^rd maxillary palp segments and by the presence of forks II, IV, V in forewings and by the presence of forks II and V in hind wings. The new species is distinguished from all other species of Palerasnitsynus by the typical dark spiny head of each harpago apex facing each other with their spiny heads (Fig. 4B) . The elongate needle-like intermediate processes terminate in a ventrally inclined tip. However, they do not extend longitudinally beyond the medio-lateral process of the coxopodite (Fig. 4C).

Bipectinata orientalis was not originally placed in the family Odontoceridae, but was initially assigned to Calamoceratidae (Wichard et al. 2020), because the presence of wing fork IV on the forewing is not common to extant Odontoceridae. Nevertheless, characteristic features of the family Odontoceridae are synapomorphically present in the genus Bipectinata, such as five-segmented maxillary palps with a terminal segment not flexible or annulated, lack of ocelli, tibial spur formula 2/4/4; in forewings fork I present, discoidal cell closed and median cell absent. In addition, genus Bipectinata is closely related to the odontocerid genus Palaeopsilotreta, whose common synapomorphies involve a variable forewing media and the bipectinate antennae (Fig. 5B).

Figure 5. 

Bipectinata orientalis Wichard et al., 2020b. A. Male in ventral view; B. Bipectinate antenna; C. Plesiomorphic forewing venation with five apical forks.

In trichopteran adults a complete set of five apical forks on the forewings is clearly a plesiomorphic character (Comstock 1918; Holzenthal et al. 2007). A reduction of the original wing venation and the reduction of apical forks are derived in many adults, especially within the superfamily Leptoceroidea. However, the extinct Bipectinata orientalis from the middle Cretaceous is characterized by the original arrangement of five apical forks in the forewing venation (Fig. 5C). This feature distinguishes it from the closely related species of the genus Palaeopsilotreta.

Lepidochlamus nodosa Wang et al., 2022.

(based on Wang et al. 2022). Ocelli absent; antenna longer than forewing, at least 71 flagellomeres preserved; maxillary palpus five-segmented, terminal palpomere V longest, not annulated, shorter than combined lengths of preceding four palpomeres. Male forewing with forks I, III, and V; all crossveins absent. Hind wing covered with a single layer of angustifoliate scales; wing venation unknown. Tibial spur formula 2/4/4.

The monobasic family Lepidochlamidae Wang et al., 2022 is transferred to the Integripalpian infraorder Brevitentoria and to its superfamily Leptoceroidea: Lepidochlamus nodosa is characterized by the absence of ocelli and by the presence of the five-segmented maxillary palps with terminal segment not annulated, the antennae longer than forewings and the mid-tibia with preapical and apical pairs of spurs. The combination of these morphological features clearly points to the superfamily Leptoceroidea (Ross 1967; Weaver 1983, 1984; Frania and Wiggins 1997; Morse 1997).

According to Wang et al. (2022), the “Lepidochlamidae, whose hindwings are covered with scales, are the sister group of all other caddisflies (Eutrichoptera).” But as a member of the monobasic family Lepidochlamidae of the superfamily Leptoceroidea it cannot be the oldest representative of the order Trichoptera, forming a sister group relationship to all other Trichoptera, as suggested.

The establishment of the new taxa by Wang et al. (2022) is an overestimation of the scales on its hind wings. Scales on the hind wings of Brevitentorian species do not enforce the exceptional position of the “early caddisfly evolution” The scales on the hind wings are not a unique feature. Single-layered scales also cover other hindwings, e.g. Helicopsyche kariona Ross, 1975, Helicopsyche boularia Ross, 1975 (see Johanson 1998) and both wings together e.g. Helicopsyche megalochari Malicky, 1974 as well as forewings, e.g. Lepidostoma americanum Flint and Wiggins,1961, Oecetis pechana Mosely & Kimmins, 1953. In xiphocentronid genera Drepanocentron and Abaria scales are found on fore- and hindwings as well on hindwings only (Schmid 1982). Scales on the wings (also called scale-like setae or scaloid setae) are well known in Trichoptera families and are probably derived from primitive setae.

In addition, the wing vein reduction in general and here the forewing venation reduction of Lepidochlamus nodosa is clearly phylogenetically derived. The plesiomorphic complete set of five apical forks is reduced by the loss of forks II and IV, which is common in some families of Brevitentoria as well as in its family Lepidochlamidae. Moreover, the nygmata in fork II and occasionally in the thyridial cell may be absent, and also the crossveins that would occlude the discoidal, medial, and thyridial cells, are not discernable most likely due to the embedding condition in amber. In my experience, the crossveins and nygmata are very difficult or impossible to recognize in amber. Only a comparison of several specimens of the same species allows a reliable statement about the presence or absence of the nygmata and the cross veins. The fossil Lepidochlamus nodosa is based on a single specimen, moderately preserved in mid-Cretaceous Burmese amber, kept as holotype no. CNU-TRI-MA-2015501, in Capital Normal University, Beijing, China.

Palleptocerus grimaldii Wichard & Müller, 2022.

(based on Wichard and Müller 2022). Tibial spur formula 2/4/4. Antennae longer than forewings, flagellomeres cylindrical, elongate. Maxillary palps are five-segmented, terminal segment not annulated. Male forewing fork I and V present, discoidal cell absent. Hind wing exclusively fork V present.

Mail-specimen deposited in the Systematic Entomology Collection of Hokkaido University Museum, Japan, inventory number: SEHU-54040 (ex coll. Ryoichi B. Kuranishi: Burmite 2).

The fossil is embedded in an oval and polished piece of amber. The adult insect is completely preserved and clearly visible in dorso-ventral aspect. The wings are folded over the body like a saddle roof, making it difficult to see the hind wings. Head is visible, long antennae incomplete in length. Legs also present. In male genitalia, only the anterior paired inferior appendages are often clearly visible ventrally, further genital structures implied visible.

The new species is dedicated in honor of the Japanese entomologist and scientist Ryoichi B. Kuranishi. I got to know and appreciate Ryoichi on the occasion of the 17^th International Symposium on Trichoptera in Lunz, Austria, September 2022.

Head: Laterally protruded compound eyes. Ocelli not present. Filiform antennae longer than forewings – incomplete in length, probably 30–40 flagellomeres; scapus conically thickened, pedipalpus small and globular; flagellomeres cylindrical, elongate (Fig. 6B). Five-segmented maxillary palps present, 5^th segment not annulated. Labial palps three-segmented, terminal segment longest.

Figure 6. 

Palleptocerus kuranishii sp. nov. in mid–Cretaceous Burmese amber, male holotype (inventory number: SEHU-54040). A. Male in lateral view; B. Excerpt of the antenna with cylindrical, elongate flagellomeres; C. Drawing of the forewing venation; D, E. Male genitalia with paired inferior appendages in ventral view.

Wings (Fig. 6C): The forewings about 6 mm long. Venation Sc and R1 straight running parallel to the wing margin. R2 + R3 forming fork I present and R4+5 simple, discoidal cells absent. Media two-branched in M1+2 and M3+4. Cu1 two-branched in Cu1a and Cu1b, forming fork V. Crossvein m-cu closing the long thyridial cell. Venation Cu2 running into A at crossvein between Cu1b and Cu2, then A with Cu2 reaching wing margin.

Tibial spurs : 2/4/4.

Genitalia (Fig. 6D, E): In ventral view, the male genitalia equipped with a pair of inferior appendages, each consisting of a dark coxopodite, narrow at the base, distad slightly broadened, overall slightly conical bent, and attached an apically attached harpago slender than the coxopodite, tapers and curves slightly toward the genital middle.

Ocelli absent. Antennae longer than forewings, flagellomeres elongate. Maxillary palps five-segmented, terminal segment not annulated. Forewings light brown, slightly narrow and apically rounded. In male forewing venation with forks I and V present, discoidal cells open and thyridial cells closed, long. Tibial spurs: 2/4/4. Palleptocerus kuranishii sp. nov. is distinguished from P. grimaldii by a slender body shape and size of 6 mm forewing length and by the form and structure of the conical inferior appendages of the male genitalia.