Psilotreta fossilis, WICHARD & MÜLLER & XU, 2021

WICHARD, WILFRIED, MÜLLER, PATRICK & XU, CHUN-PENG, 2021, The odontocerid genera Psilotreta and Palaeopsilotreta (Insecta, Trichoptera) embedded in mid-Cretaceous Burmese amber, Palaeoentomology 4 (4), pp. 331-338 : 332

Psilotreta fossilis sp. nov.

( Fig. 1 )

Type material. Male, NIGP175453 , deposited in the Nanjing Institute of Geology and Palaeontology , Chinese Academy of Sciences. Well preserved in mid-Cretaceous Burmese amber, Kachin State, Myanmar. Body well preserved; forewing in dorsal view, hindwing covered dorsally by forewing. Antennae and legs present. Male genitalia visible in ventral view .

Etymology. This new species is the first fossil Psilotreta described from the mid-Cretaceous Burmese amber.

Diagnosis. Filamentous antennae about three times longer than forewing lengths. In forewings media M reduced, here without base, apical part originating from R 4+5. In male genitalia harpagoes originate mesally on coxopodites. Therefore the extinct species belong very probably to the Psilotreta trimeresuri diagnostic speciesgroup (sensu Oláh & Johanson, 2010).

Description. Embedded in amber, conspicuous imago by long antennae, which about three times as long as elongated forewings with a length of 7 mm. Extant Psilotreta species often with antennae longer than their forewings. In forewings (7 mm in lengths) fork I about 1/3 times longer than fork II, discoidal cell closed. Fork II sessile, arising at junction of R 4+5 and crossveins. Media M reduced, simple (M 1, 2, 3, 4), without base, represented by single apical branch, originating from R 4+5; forks III and IV absent. Cu 1 running straight, apically bifurcated to fork V; Cu 2 simple, running unforked to wing margin.

Male genitalia visible ventrally, but through very cloudy amber and difficult to recognize. Only inferior appendages can be described. In ventral view inferior appendages appear narrow, elongated and two-segmented consisting of coxopodite and harpago. Shorter harpago arising from coxopodite laterally in middle and not fully reaching apical level of coxopodite. Inferior appendages covered with relatively long hairs; spines not visible at apex of harpago. Although other structures (e.g., phallic apparatus, parameres) of male genitalia cannot be clearly described, unambiguous organization of inferior appendages suggests that Psilotreta fossilis sp. nov. likely belongs to the diagnostic species group Psilotreta trimeresuri .

Remarks. The wing venation of this fossil agrees largely with those of extant Psilotreta species that also have simple media (M 1, 2, 3, 4), e. g., Psilotreta baureo Malicky, 1989 , Psilotreta illuan Malicky, 1989 , Psilotreta enikoae Oláh & Johanson, 2010 , Psilotreta kurenschikovorum Arefina-Armitage & Armitage, 2011 , all extant species from Southeast Asia.

Figures

FIGURE 1. Psilotreta fossilis sp. nov., male holotype, NIGP175453. A, Imago in dorsal view with antennae about three times longer than forewing length; scale bar = 2 mm. B, drawing of forewing venation; scale bar = 1.5 mm. C, Male genitalia embedded in dusty amber; scale bar = 0.3 mm. D, Drawing of inferior appendages; scale bar = 0.3 mm.