Ferriantenna gracenuoxichenae, Cumming & Tirant & Chen, 2024

Ferriantenna gracenuoxichenae sp. nov.

( Fig. 1C View Fig , 2 View Fig , 3 View Fig )

ZooBank: http://zoobank.org/ FDF27C53-E8D2-44B4-B985-CEE2589A2AA0

Holotype. – Amber specimen #SC4626, GM12170200548. Roughly a rounded parallelogram piece of amber, approximately 3.69 cm long, 1.96 cm wide, and 1.42 cm thick, with high clarity and 2 small inclusions (one † Archaeatropidae ( Psocodea ) and a Nematoceran (Diptera)) in addition to the herein discussed species. The herein discussed species is not obscured and close to the surface ( Fig. 1B View Fig ). Specimen partially complete yet wellpreserved, likely fourth instar. Missing the terminal two or three segments of the abdomen, the hind legs are incomplete, and the terminal antennomeres are missing. Deposited in the Montreal Insectarium ( IMQC). Unknown sex.

Type locality and horizon. – Kachin State, Myanmar; Upper Cretaceous ~98.79 ± 0.62 million years old (Shi et al.2012).At present this genus and species is only known from this stratum.

Differentiation. – At present two congenerics are known (one described ( Fig. 1A View Fig ) and the other unnamed ( Fig. 1B View Fig ); both from the same type locality and deposit ( Cumming and Le Tirant, 2021)) and these can be differentiated by antennae morphology. Within congeners, antennomeres II and III have a similar morphology, while in Ferriantenna gracenuoxichenae sp. nov. antennomeres II is relatively simple and antennomeres III has expansions on the dorsal and ventral surfaces ( Fig. 3F View Fig ).

Description. – Mostly complete nymph that appears to be fourth instar (based upon the characters of Schuh and Slater (1995): posterior margins of the hind wing buds not reaching the anterior margin of the first abdominal tergite; ocelli absent; and tarsi two-segmented). Sex unknown due to the instar stage and missing terminalia of the abdomen. The holotype specimen is relatively complete except for the terminal two or three abdominal segments, the hind femora are missing the distal ends and the remainder of the hind legs are missing, and the terminal antennomeres are missing ( Fig. 2A View Fig ).Overalllength (including antennae which are missing the terminal antennomere) 10.91 mm (measured to the end of the incomplete abdomen, therefore the actual length of the insect is slightly longer).

Head. – Antennal socket slightly protruding from the front of the head ( Fig. 3A View Fig ), approximately 0.18 long by 0.19 mm wide, with a greatest width slightly wider than the first antennomere. Head roughly rectangular, 0.75 mm long by 0.49 mm wide (without including compound eyes), including compound eyes head is 0.89 mm wide. The head vertex is relatively smooth, no notable textures or structures ( Fig. 3A View Fig ). Clypeus protruding into a stout point. The labrum is long and thin and ends in a fine point. Labium tetramerous, when fully extended the labium reaches almost to the apex of the second antennomere ( Fig. 3A View Fig ). Labiomeres of various lengths; labiomere I is 0.44 mm long, labiomere II is 1.01 mm long, labiomere III is 1.04 mm long, labiomere IV is 0.50 mm long ( Fig. 3A View Fig ). Apex of labiomere IV tapering to a fine point which hooks slightly ventrally ( Fig. 3A View Fig ). Compound eyes prominent and distinctly protrude from the head capsule, are located in the center and take up ca. one third of the lateral head margins ( Fig. 3A View Fig ).

Antennae. – Antennae likely tetramerous (in the holotype only the proximal three antennomeres are preserved but at least a fourth was present at one point judging by the socket at the apex of antennomere III; Fig. 3C View Fig ). Based on congeners, there likely was only a fourth segment at the antenna apex, no additional segments, but the morphology is unknown based on the holotype. Overall antennae lengths 6.30 mm (right) and 6.27 mm (left) [both are missing their terminal antennomeres, therefore the actual length would be even longer], notably longer than the damaged holotype body length (4.61 mm). First antennomere tubular and simple, lacking significant features, 0.52 mm long and 0.19 mm wide.

Antennomeres II and III laterally flattened. Antennomere II expansions only slightly protruding on both the dorsal and ventral surfaces (ventral slightly more prominently than the dorsal). These expansions are barely present on the proximal end and expand just slightly throughout the length to the distal end of the antennomere. These expansions are very slight, making this antennomere appear long and slender ( Fig. 3F View Fig ). Margins slightly granular, with no detectable setae. Antennomere surfaces are smooth and possibly slightly tomentose (but this shine could be from the preservation). Second antennomere length 2.90 mm and maximum width 0.19 mm. Antennomere III notably different in shape from antennomere II. The ventral expansion of antennomere III has a maximum width of 0.29 mm and is broader than the dorsal expansion which has a maximum width of 0.17 mm. The ventral expansion steadily expands from the proximal margin for ca. the first third, contracts slightly, then runs parallel with the antennomere shaft for the central third of the expansion, then the distal third reduces until the distal end of the antennomere ( Fig. 3C View Fig ). The dorsal expansion of antennomere III slightly increases in width until near the middle of the antennomere, then decreases in width only slightly throughout the remainder of the length until the expansion terminates on the distal margin ( Fig. 3C View Fig ). Margins finely granular, and no observable setae. Surfaces of antennomere III relatively smooth. Antennomere III 2.88 mm long and has a maximum width of 0.45 mm. Fourth antennomere missing in the holotype.

Thorax. – Thorax centrally deteriorated, but the margins are moderately intact. Thorax surfaces and margins are smooth and lack fine projections/ notable textures. Pronotum roughly hexagonal with the posterior slightly wider than the other margins. The lateral margins expand to approximately the mid-length then contract to the posterior. Overall pronotum length 0.76 mm, anterior width 0.50 mm, posterior width 0.57 mm, maximum width 0.80 mm. Mesonotum and metanotum a similar shape as the pronotum. Mesonotum length 0.69 mm and greatest width 0.92 mm. Metanotum length 0.58 mm and greatest width 0.98 mm.

Legs. – All legs of a similar morphology, only slight differences in length and thickness differentiate them ( Fig. 3B View Fig ). The profemora and mesofemora are of uniform widths (ca. 0.23 mm; Fig. 3B View Fig ) and the metafemora are slightly thicker (maximum width 0.26 mm). All femora simple, tubular, no ornamentation. Protibiae and mesotibiae of uniform widths and are longer than the femoral shafts. Protibiae and mesotibiae simple, tubular, with no ornamentation. Femora tubular, with surfaces that are smooth. Tibiae are approximately half as wide as the femoral widths. Tibiae on the proximal end start out smooth but about halfway through the length short, sparse setae start and become denser throughout the remainder of the tibiae length until there is dense but short setae on the distal ends of the ventral tibiae surface. The dense but short setae continue on under the tarsomeres ( Fig. 3D View Fig ). Tarsi each with two tarsomeres, and the apex of each two distinct tarsal claws, each with a prominent pulvillus. Leg segment lengths: profemora 2.46 mm, mesofemora 2.27 mm, metafemora 1.95 mm (distal ends broken, metafemora incomplete), protibiae 2.29 mm, mesotibae 2.37 mm, metatibiae missing from the holotype.

Abdomen. – Abdomen notably damaged in the holotype. Most of the abdomenhas significant deterioration and is curved towards the amber surface where the terminal two or three abdominal segments are missing ( Fig. 2A View Fig ). Greatest width approximately 0.96 mm. Abdomen without detectable external structures, margins appear to be ca. parallel sided with smooth transitions from one segment to the next.