Allorapisma chuorum, Makarkin, Vladimir N. & Archibald, Bruce, 2009

Makarkin, Vladimir N. & Archibald, Bruce, 2009, A new genus and first Cenozoic fossil record of moth lacewings (Neuroptera: Ithonidae) from the Early Eocene of North America, Zootaxa 2063, pp. 55-63 : 57-60

Allorapisma chuorum sp. nov.

Figs. 2–3

Etymology. The specific epithet is formed from the surname of the Chu family of Kirkland, Washington (see Acknowledgements), the collectors of the holotype, in recognition of their generous contribution to science in the donation of this specimen.

Holotype. Specimen SR 08-14-01 (part only), collected on June 23, 2007 by the Chu family at the Boot Hill exposure B4131, and deposited in SRIC. A nearly complete, beautifully preserved forewing (probably left).

Paratype. Specimen SRUI 08-04-01 (part only), collected on July 15, 2007 by Karl Volkman at the Corner Lot exposure A0307, and deposited in SRIC. A nearly complete, beautifully preserved forewing (probably right).

Type locality and horizon. Tom Thumb Tuff Member of the Klondike Mountain Formation, Republic, Washington, U.S.A.; Early Eocene.

Diagnosis. As for genus.

Description of the holotype. Forewing oval, with rounded apex, approximately 16 mm long, 6.2–6.3 mm wide. Trichosors, nygmata not detected. Costal space moderately expanded basally (1.3 mm maximum width), narrowed apically. Subcostal veinlets closely spaced, mostly simple proximally (one anomalous, with loop-like doubling), forked distally; slightly oblique, strongly bent towards apex near C in basal portion of costal space, more strongly oblique in its apical portion. Humeral veinlet well-developed, incompletely preserved. Costal gradate series represented by few crossveins in basal part of wing, parallel with, close to costal wing margin. Sc thick in proximal half, not fused with R1 distally. R1 with marginal fork only, entering margin before wing apex. Subcostal space rather broad for entire length except basally; numerous (approximately 22 as preserved), more or less regularly spaced crossveins. R1 space (between R1, Rs) very broad medially, maximum width approximately as broad as basal portion of costal space (1.1–1.2 mm); several crossveins, mainly in medial portion. Rs originating at acute angle relatively far from wing base, smooth, not zigzagged for almost entire length, only slightly zigzagged in distal portion, entering margin before wing apex; proximal branches short, irregular, fused with MA; four distal branches free, connected by few crossveins. MA, MP separated. MA fused with R basally, strongly concave, originating near origin of Rs, entering wing margin well distad mid-point. Oblique, strongly concave crossvein (basal part of MA?) between MA, MP. MP basally not fused with R, stout, with peculiar configuration distally: both branches of primary fork at equal angle to stem; anterior branch with posteriorly directed pectination, posterior branch with anteriorly directed pectination. MP, Cu convergent towards wing base, appear fused. CuA stout in proximal half, running nearly parallel to MP for most part, then to posterior branch of MP, with four pectinate branches connected by several crossveins. Origin of CuP poorly visible as preserved; CuP poorly developed, much thinner than CuA, connected with it by five crossveins, fused distally with most proximal branch of CuA [alternatively, apparent ‘CuP’ a false vein formed by several aligned crossveins between branches of CuA (if so, short, fused with CuP)]. Several crossveins between MA, MP; MP, CuA. 1A [alternatively, CuP] long, with few branches. 2A [alternatively, 1A] rather short, simple, connected with 1A [alternatively, CuP] by two short crossvein basally, by long oblique crossvein distally. 3A [alternatively, 2A] simple, appears fused distally with 2A [alternatively, connected by long oblique crossvein]. Jugal lobe not detected as preserved. Wing membrane tinged with brown to dark brown.

Description of the paratype. Forewing oval, with rounded apex, approximately 16.5 mm long, 6.3 mm wide (hind wing margin poorly preserved). Trichosors, nygmata not detected. Costal space moderately expanded basally (1.3 mm maximum width), narrowed apically. Subcostal veinlets closely spaced, simple proximally, forked distally; slightly oblique, strongly bent towards apex near C in basal portion of costal space, apical portion more strongly oblique. Humeral veinlet well-developed, with three branches. Costal gradate series represented by few crossveins in basal part of wing; running parallel, close to costal wing margin. Sc thick in proximal 1/3, not fused with R1 distally. R1 with shallow marginal fork, short distal forked branch, terminating on margin before wing apex. Subcostal space rather broad for entire length except basally; numerous (approximately 30), more or less regularly spaced crossveins. R1 space very broad medially, maximum width approximately as broad as basal portion of costal space (1.1 mm); many crossveins in proximal half, lesser crossveins in distal half. Rs originating at acute angle relatively far from wing base, smooth, lacking any zigzag features for almost entire length, entering margin before wing apex. Six proximal branches [alternatively, crossveins] short, fused with MA; next two branches much longer, sinuate, fused with MA; distal seven branches free, irregular, simple (except for one branch with deep branching, another represented only as basal portion), connected by crossveins, not forming regular gradate series. M represented by separate MA, MP. MA fused with R basally, strongly concave, simple, reaching wing margin well after mid-point. MP not fused with R basally, peculiarly configured distally: both branches of primary fork at equal angle to stem; anterior branch with posteriorly directed pectination, posterior branch with anteriorly directed branch (incompletely preserved). Fork of Cu not preserved. CuA stout proximally, running nearly parallel to MP, then posterior branch of MP, with three pectinate branches connecting with several irregularly arranged crossveins. Several crossveins between MA, MP; MP, CuA. CuP, anal veins, jugal lobe not detected as preserved. Wing membrane tinged with dark brown.

Remarks. The apparent absence of trichosors and nygmata in this species is possibly an artefact. In the forewing of extant Rapisma species, these characters are poorly developed and often not clearly discernible.

Figures

FIGURE 2. Allorapisma chuorum gen. et sp. nov., holotype specimen SR 08 - 14 - 01. A, photograph. B, drawing of the forewing. Scale bar = 5 mm.

FIGURE 3. Allorapisma chuorum gen. et sp. nov., paratype specimen SRUI 08 - 04 - 01. A, photograph. B, drawing of the forewing. Scale bar = 5 mm.