Alacrena, Vea & Grimaldi, 2015

Vea, Isabelle M. & Grimaldi, David A., 2015, Diverse new scale insects (Hemiptera: Coccoidea) in amber from the Cretaceous and Eocene with a phylogenetic framework for fossil Coccoidea, American Museum Novitates 2015 (3823), pp. 1-80 : 43

Alacrena , new genus

TYPE SPECIES: Alacrena peculiaris , n. sp., by present designation and monotypy.

OCCURRENCE: Myanmar: Kachin: near Tanai village. Albian-Cenomanian boundary.

ETYMOLOGY: The genus name comes from the Latin ala, meaning “wing,” crena, meaning “notch,” This refers to the notch found on the apex of the forewing. Gender: feminine.

DIAGNOSIS: This genus is peculiar by the combination of the following characters: body minute, head large, compound eyes bulging, each with fewer than 100 ommatidia; antennal segments filiform, with capitate and fleshy setae on apical segment (vs. absent in archaeococcoids with compound eyes); wings hyaline, with a subcostal ridge extending to ¾ wing length, cubital ridge present ending at apical margin with a notch (vs. absent in all Coccoidea ); hamulohalteres long and narrow; legs slender, tarsus 1-segmented, tarsal digitule capitate; claws narrow and elongate, almost straight, claw digitules and denticles absent; tubular duct on abdominal tergites absent; genital segment exceptionally elongate.

SPECIES INCLUDED: A. peculiaris , n. sp.

COMMENTS: Alacrena seems most similar to Kozarius , n. gen., because of the minute body size, head shape, bulging compound eyes, and the elongate penial sheath. However, they differ by the wing structure ( Alacrena has a notch on the apex of the forewing, which is also unique in Coccoidea ) and the absence of tubular ducts (present in Kozarius ).

The phylogenetic results retrieved Alacrena within the lineage including Lebanococcus and Kozarius , although the exact relationship remains unresolved. Lebanococcus and Alacrena share the presence of only subcostal and cubital ridges on the forewings, and the absence of tubular ducts. Despite the presence of well-developed compound eyes, Lebanococcus has a very different, telescopic abdomen ( Koteja and Azar, 2008), shortened antennae, wings with a pterostigma and an anterior flexing patch, which are completely absent in Alacrena . The placement of Alacrena needs to be further investigated with additional, better preserved specimens (the unique specimen has all thoracic structures damaged). For now, the genus is considered incertae familiae.