Burmecaelinus yungyenwangae, Schall & Cumming & Lian & Husemann, 2025

Species: Burmecaelinus yungyenwangae sp. nov.

Figs. 1–3 View FIGURE 1 View FIGURE 2 View FIGURE 3

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Etymology: Patronym. The species is named after Yungyen-Wang, mother of the third author (ZL), to thank her for her years of support and encouragement.

Locality and horizon: Tanai, Kachin State Burma, Myanmar, an amber mining location. The amber from Tanai is estimated to be ca. 99 My old.

Holotype: The holotype, an adult female, is currently in the collection of the third author (ZL), catalogued as collection number OA-2025-03-WYY P.S. The holotype will eventually be transferred to the Asian Amber Biological Museum, Tainan, Taiwan upon the museum’s completion.

Diagnosis: Pronotum with dorso-anterior and dorso-posterior carinae, as well as dorso-lateral carina on each side. Protibia apically with two spines. Forewing venation rather dense, with at least five well-developed longitudinal veins. Abdominal apex with epiproct with two lateral pointed extensions and one medial rounded extension. Subgenital plate short. Cerci half the length of paraproctal lobes; one-segmented and pointed with long setae. Paraproctal lobes cylindrical in shape, with long apical setae. Valves of ovipositor visible, slightly longer than cerci.

Description

Measurements (mm): Body length (tip of fastigium to tip of paraproctal lobe) 7.1. Dorsal length of pronotum (midline) 1.15. Dorsal width of pronotum along anterior margin 1.3; along posterior margin 1.75. Prothoracic leg: femur length 1.0; tibia length 0.85; tarsus length (including tarsal claws) 0.76. Mesothoracic leg: femur 1.16; tibia 1.3. Metathoracic leg: femur 4.0; tibia ca. 3.3. Forewing 2.8.

Head: Hypognathous. Antennae moniliform with eight segments (including scape and pedicel). Antennomeres longer than wide. Antennal scapes enlarged. Compound eyes egg-shaped, protruding from head dorsally. Fastigium between compound eyes very narrow.

Thorax: Pronotum trapezoid in dorsal view. Anterior margin concave, posterior margin convex, distinctly wider than anterior margin.An anterior and posterior dorsal carina, as well as two lateral carinae (one on each side) present. Entire surface of pronotum very rugged. Forewings present, ca. half the length of abdomen. Dense in venation with ScA, ScP, R + MA1, MA2 and CuP visible as distinct single longitudinal veins.

Legs: Prothoracic leg with femur greatly inflated and bearing long setae. Tibia normal (not inflated), showing similar setae; apically bearing two small spines. Tarsus two-segmented with two tarsal pads; apically bearing two curved claws. Mesothoracic leg unspecialized i.e. neither femur nor tibia inflated. Femur proximally with two long setae. Tarsus two-segmented with two claws. Metathoracic leg heavily inflated along the entire length. Several longitudinal carinae and semilunar process present. Tibia with serration that becomes prominent towards apex (i.e. the spines become larger). Apex of tibia with two subapical and two apical spurs of similar length. Tarsus not visible.

Abdomen: Epiproct with three extensions, two laterally rather pointed, one in the middle that is broader and more rounded. Cerci rather short and triangular with long setae. Paraproctal lobes prominent, cylindrical in shape and about twice the length of cerci, with long setae towards apex. Ovipositor valves visible. Subgenital plate rather short, being distinctly surpassed by the other abdominal structures.

Remarks: Burmecaelinus yungyenwangae sp. nov. is assigned to Burmecaelidae based on the following combination of characters:head with compound eyes protruding dorsally and fastigium between compound eyes very narrow; antennae moniliform with eight segments; tarsi of pro- and mesothoracic leg two-segmented; metafemur greatly inflated along its entire length; metatibia with serration and two subapical as well as apical spurs.

It is further assigned to the genus Burmecaelinus due to the presence of two protarsal pads and the subgenital plate being short, only reaching to the base of the paraproctal lobes. Table 1 View TABLE 1 shows characters of taxonomic importance for Burmecaelidae for all four specimens of the family reported so far ( Uchida et al., 2024; Hu et al., 2024; this study). The pronotum of all four specimens shows a similar pattern of lateral carinae as well as posterior and anterior carinae. The four additional latitudinal carinae on the pronotal disc of ECNU-AM-0079 (cf. Burmecaelinus armis ) reported in Hu et al., (2024) are likely not a reliable character in an amber fossil; this was acknowledged by the authors as well. ECNU-AM-0079 exhibits a different general shape of the pronotum in that it appears to be wider than long compared to the other three specimens. However, we think this may be the result of dorso-ventral compression of the specimen, effectively squashing the pronotum, as damage to the fossil can be seen in the ruptured head and abdomen. The two tarsal pads described by Uchida et al. (2024) for the holotype of B. armis are also present in B. yungyenwangae . However, they are not mentioned in the description of the ECNU specimens. The metatibia is serrated in all specimens. The abdominal apex is where the specimens differ most: the holotype of B. armis , as well as the second specimen reported by Hu et al. (2024), have an epiproct with a lateral extension on each side that is short and blunt and a medial extension that is round with a narrow inward fold. In Moban zhengzhemini Hu & He, 2024 the inward fold of the medial extension is missing. The same is true for B. yungyenwangae , and this species has the two lateral extensions which are pointed. The cerci of B. armis are of the same length as the paraproctal lobes (the structure interpreted as the ovipositor in the original description of B. armis is more likely to represent the paraproctal lobes). In ECNU-AM-0079 only one cercus is preserved. This cercus appears to be longer than in the holotype of B. armis , but the paraproctal lobes are not seen in this specimen. In M. zhengzhemini , two very short structures on either side of the abdomen were interpreted as probable cerci and paraproctal lobes. However, these structures also resemble ovipositor valves, as are found in Ripipterygidae Ander, 1939 and our specimen of B. yungyenwangae . The identity of these structures, therefore, is questionable. The cerci of B. yungyenwangae are only about half the length of the paraproctal lobes. Lastly, the subgenital plates of B. armis and B. yungyenwangae are similar. Both are short, reaching only to the base of the paraproctal lobes. In contrast, the subgenital plates of the ECNU specimens are elongated and possess numerous long setae. They have a distinct medial appendix that extends up to the length of the cercus in ECNU-AM-0079.

In conclusion, we argue that the morphology of the pronotum and serration of the metatibia is relatively similar in all four specimens. The epiproct only shows small variation, which may not be sufficient for taxonomic separation (the inward fold could perhaps be due to sexual dimorphism). The ECNU specimens differ from the holotypes of B. armis and B. yungyenwangae by the morphology of their subgenital plates and the absence of protarsal pads. The structure of the cerci and paraproctal lobes cannot be determined for either ECNU specimen. Burmacelinus armis differs from B. yungyenwangae mainly in the morphology of the paraproctal lobes. Thus, we suggest that ECNU-AM-0079 is perhaps more likely to belong to the genus Moban rather than Burmecaelinus .

Hu et al. (2024) described a structure on the dorsal side of the ECNU specimens as a “scutellum” or posterior process of the pronotum (in relation to the posteriorly extremely elongated pronotum of Tetrigidae Rambur, 1838 ). However, judging by the same, well visible area in B. yungyenwangae , it seems more likely that this structure is part of the forewing instead.