Horizon

Cumming, Royce T., Engel, Michael S., Lian, Zhendong & Ulitzka, Manfred R., 2024, Small, intricate, and beautiful; a new species of lophioneurid from the Cretaceous (Insecta: Thripida: † Lophioneurida), Faunitaxys 12 (58), pp. 1-10 : 2-5

Horizon and age. – Upper Cretaceous ~98.79 ± 0.62 million years old ( Shi et al., 2012).

Differentiation. – There are two other genera known from the clade, Burmacypha Zherikhin, 2000 , and Iotacypha Shcherbakov et al., 2024 both of which are superficially similar due to the forewings with intricate, tessellating hexagonal patterns and an apical fusion of MP with CuA which creates an enclosed, large central cell (although the shape of this enclosed cell allows differentiation).

Retiptera gen. nov. can be differentiated from Burmacypha by multiple venation differences in both the forewing and the hindwing, as well as by notably differing antenna morphology. In Burmacypha the Sc is short, only running ca. ¼ the way through the wing length and it hugs the costal margin ( Fig. 3A) versus in Retiptera gen. nov. the Sc is long (ca. ½ of the forewing length; Fig. 3C) and the Sc has a significant gap between it and the wing margin, with the central ⅓ of the Sc running parallel with the margin, giving the cell a trapezoidal appearance ( Fig. 3C). Additionally in the forewing, Burmacypha has a significantly differing set of radial veins; the RA splits near the proximal third of the wing and is angled anteriorly and it has a bifurcate Rs with the Rs1 forming near the middle of the wing length and the Rs2 near the wing apex ( Fig. 3A), versus Retiptera gen. nov. which has the radial veins only forming the RA ca. ⅗ of the way through the wing length and a singular radial sector (Rs1) splitting near the posterior ⅓ of the wing length and terminating on the apex ( Fig. 3C). An additional feature in the forewings for differentiation is the presence/absence of a first anal vein (1A) as Burmacypha lacks the vein while Retiptera gen. nov. has the first anal prominent (as thick as the other forewing veins) and running ca. ⅖ of the way through the wing length ( Fig. 3C). The central cell of the forewings formed by the fusing of MP+CuA also differentiates these species as Burmacypha has this cell formed by seven straight sides and forms roughly an oval ( Fig. 3A) versus Retiptera gen. nov. which also has seven sides, but the R+M fused vein is distinctly curved, giving the central cell an overall reniform shape ( Fig. 3C). Within the hindwings the genera can be separated by the presence or absence of the cubitus as Burmacypha has the vein prominently present ( Fig. 3A) and Retiptera gen. nov. lacks a cubitus ( Fig. 3C). Additionally, the hindwings are of drastically differing sizes, with Burmacypha having a well-developed hindwing only slightly smaller than the forewing ( Fig. 3A) versus Retiptera gen. nov. which has a highly reduced hindwing notably shorter and thinner than the forewing ( Fig. 3C). The antennae of the Retiptera gen. nov. differ as Burmacypha has seven-segmented antennae, with the scape and pedicel thick and distinctly longer than broad with the flagellomeres significantly thinner than the scape and pedicel and the individual flagellomeres long and filiform versus Retiptera gen. nov. which has eight-segmented antennae where the scape and pedicel are short and stout and the flagellomeres are long and only slightly thinner than the pedicellus, not filiform ( Fig. 4B).

Retiptera gen. nov. can be differentiated from Iotacypha by multiple venation differences in both the forewing and the hindwing, as well as by notably differing antenna morphology. In both genera the forewing Sc is long (~½ the wing length) but in Retiptera gen. nov. the Sc has a significant gap between it and the wing margin, with the central ⅓ of the Sc running parallel with the relatively straight margin, giving the cell a trapezoidal appearance ( Fig. 3C) versus in Iotacypha the Sc is widest in the proximal ¼ before the Sc reaches toward the wing margin and then runs parallel with the arcing margin until it terminates near the middle of the forewing length (giving the cell a long, thinner curved appearance; Fig. 3B). Additionally in the forewing the genera have significantly different sets of radial/medial veins; in Iotacypha there is a fused Rs1+MA vein emerging from the large central cell which then bifurcates into the Rs1 and MA which run diverging to the wing apical margins ( Fig. 3B) versus in Retiptera gen. nov. the Rs1 and MA emerge independently from the large central cell and run straight to the forewing margins ( Fig. 3C). An additional feature in the forewings is the first anal vein (1A) as Retiptera gen. nov. has 1A running parallel with the forewing margin for ca. ⅓ of the wing length and CuP terminates on the 1A ca. ½ way through 1A’s length ( Fig. 3C) while Iotacypha has the first anal only running for ca. ⅙ of the way through the wing length, arcing towards the margin (not running parallel), and the CuP does not terminate on the 1A, instead reaching past it to the wing margin ( Fig. 3B). Also in the forewing, the large central cell in Retiptera gen. nov. is seven sided and approximately reniform in shape ( Fig. 3C) versus Iotacypha which has a four sided cell where the two proximal most veins are long and arcing, giving the central cell somewhat of an arrowhead shape ( Fig. 3B). Forewing sclerotization also differs between the two genera, as Retiptera gen. nov. has a pattern appearing as a regular hexagon tessellation with most cells hexagonal in shape and the sclerotization between the cells is thin and angular,

C

giving the membrane a honeycomb appearance ( Fig. 3E) versus Iotacypha which has a pattern more akin to a rounded semiregular tessellation pattern where the cells are circular and the sclerotization is thick, making it appear more like the cells are punch marks in the membrane ( Fig. 3D). The size of the hindwings differentiates the genera as Retiptera gen. nov. has a highly reduced hindwing, many times longer than wide, giving it a long thin appearance ( Fig. 3C) versus the Iotacypha hindwing which is well-developed, only slightly shorter and narrower than the forewing ( Fig. 3B). The antennae of the two genera differ significantly as Retiptera gen. nov. has eight-segmented antennae, with the scape and pedicel thick and stout with the flagellomeres slightly thinner than the pedicel and the individual flagellomeres long (three to four times the length of the pedicel; Fig. 4B) versus Iotacypha which has seven-segmented antennae where the scape, pedicel, and the flagellomeres are short and stout, with the flagellomeres ca. half the width of the pedicellus and only slightly longer ( Fig. 1E). Additionally, the flagellomeres of Iotacypha have several long and thick setae on each flagellomere, some longer than the flagellomere’s length ( Fig. 1E) versus Retiptera gen. nov. flagellomeres which lack long setae, instead at most with only short pubescence that is almost not noticeable ( Fig. 4B).

Description. – Average sized lophioneurid (~ 1.01 mm, from the front of the head to the apex of the abdomen in the holotype). Forewing membrane with a regular tessellating hexagonal pattern; Sc long (ca. half wing length); R, M, and Cu fused forming a long common stem; apical fusion of MP with CuA which creates an enclosed, large central cell. Forewing large central cell approximately reniform in shape. All major forewing veins marked with stout, evenly spaced setae (including along the costal margin). Hindwing simple with only the R and M present. R+M fused for the first half of hindwing length, then M diverges perpendicularly from the R+M stem; R is bifurcate with the RA and Rs terminal behind the wing apex. Antennae long and eight-segmented with long, unadorned segments. Legs straight and long with distinct setae throughout their lengths. Tarsi ca. ½ to ⅓ as long as tibiae; claws small.