Palaeopsilotreta, Wichard & Wang, 2017

Wichard, Wilfried, Espeland, Marianne, Müller, Patrick & Wang, Bo, 2020, New species of caddisflies with bipectinate antennae from Cretaceous Burmese amber (Insecta, Trichoptera: Odontoceratidae, Calamoceratidae), European Journal of Taxonomy 653, pp. 1-17 : 11

Female of genus Palaeopsilotreta

Fig. 4 A–D

Material examined

MYANMAR – Kachin State • 2 ♀♀; exact locality unknown; Mid-Cretaceous Burmese amber inclusions; former Patrick Müller collection, BuB2572a and BuB2572b ; ZFMK-TRI000815 , ZFMK- TRI000816 .

Remarks

In a small piece of Burmese amber (ZFMK-TRI000815) two caddis flies, a male and a female, are embedded 1 mm apart ( Fig. 4A ). The male is identified as Palaeopsilotreta xiai (antennae with 12 bipectinate flagellomeres plus 8 last flagellomeres simple; in forewing, media simple, unbranched); the nearby female seems most likely to be the same species as the male.

In addition to morphological similarities, there is a clear sexual dimorphism. The female has simple, non-pectinate antennae. Furthermore, the forewing venation is different; the female has the media forked into M1+2 and M3+4 whereas the media in male Palaeopsilotreta xiai is simple, unbranched. Since we cannot be sure that these females belong to P. xiai even though one of them was found in close proximity to a male, we here leave both unplaced in the genus Palaeopsilotreta .

Description

Female embedded in a further separate piece of amber (ZFMK-TRI000816). Body and wings light brown ( Fig. 4B ).

HEAD. Antennae simple, not bipectinate, consisting of long scapus, short pedicellus, first flagellomere as long as pedicellus, both together about as long as scapus, followed by about 26 successive simple flagellomeres without rami. Antennae about as long as forewings. Maxillary palps 5-segmented and labial palps 3-segmented, their terminal segments not flexible or annulate. Head with ocelli absent, setose warts on head and thorax badly preserved and macerated.

FOREWINGS. 3.4 mm in length ( Fig. 4D ). Radius R1 running towards wing margin, but turns slightly towards fork R2 without reaching it. Forks I and II of Rs present, sessile, branching at same level. Discoidal cell probably closed by crossveins. [Generally, crossveins in wings embedded in amber often difficult or impossible to detect.] DC smaller, about half as long as fork I, fork II. Media branching into M1+2 and M3+4. Fork M longer than forks I, II and V, reaching up to half the length of discoidal cell. Cu1 running straight, apically bifurcated into fork V (Cu1a – Cu1b); crossvein m-cu present, therefore thyridial cell present. Cu2 simple, unforked, with a crossvein to Cu1b. Anal veins probably complete. Hindwings covered by forewings. In ventral view not clearly visible.

TIBIAL SPURS. 2/4/4.

FEMALE TERMINALIA ( Fig. 4 C ). External structures much simplified, embedded and slightly twisted in amber, therefore difficult to interpret.

Figures

Fig. 4. Palaeopsilotreta xiai Wichard & Wang, 2017. A. Male and possible female in one Baltic amber piece (ZFMK-TRI000815).B. Female with simple, filiform antennae in dorsal view (ZFMK-TRI000816). C. Female genitalia, as far as visible in cloudy amber (ZFMK-TRI000816). D. Drawing of female forewing. E. Head of male (ZFMK-TRI000811) in dorsal view with antennal, posterior and pronotal setose warts (s.w.). — F. P. burmanica sp. nov. (ZFMK-TRI000813), head of male with maxillary palps (mp), labial palps (lp) and basal bipectinate antennae with scapus (sc) and pedicellus (pe).