Firkantus freddykruegeri Viertler, Klopfstein

Viertler, Alexandra, Urfer, Karin, Schulz, Georg, Klopfstein, Seraina & Spasojevic, Tamara, 2023, Impact of increasing morphological information by micro-CT scanning on the phylogenetic placement of Darwin wasps (Hymenoptera, Ichneumonidae) in amber, Swiss Journal of Palaeontology (30) 142 (1), pp. 1-27 : 15-17

Firkantus freddykruegeri Viertler, Klopfstein & Spasojevic sp. nov. ( Fig. 7 )

urn:lsid:zoobank.org:act:3BA05039-B298-4D6D-937F-129D22B1EB10

Etymology: Named after the fictional character Freddy Krueger from the horror movie “A nightmare on Elm Street”. Alludes to the shared characteristics of the fictional character and the fossil species—long claws and arolium.

Type specimen: Holotype: male (#NHMD_876111, A.K. Andersen, 28–3-1968). Baltic amber. Location: West Coast of Jutland ( Denmark). Deposited in Denmark, Natural history museum in Copenhagen.

Type condition: The surface has cracks. The holotype is only visible through one side of the amber piece, and details like mouth parts, the propodeal spiracle, and spiracles on T 2– T 4 are veiled by whitish coatings, often found in Baltic amber (Weitschat & Wichard, 1998). The opposite side is obscured by another inclusion of a Tachyporinae (Staphylidinae) and some blurring.The surface of this amber piece cracked further due to an accident and was cast in resin to stabilize it for future studies.

Description: Body 5.7 mm. Colouration difficult to interpret.

Head. Face separated from clypeus, evenly convex. Mandibles either unidentate or bidentate with very small lower tooth, strongly tapered with apex width about 0.3– 0.5 base width, length 2 × base width; visible tooth looks pointed. Malar space short, between 0.2 and 0.5 × of mandible base width. Maxillary palps with five, labial palps with four segments. Clypeus small, slightly convex or truncate, transverse division unclear, apical margin without tubercles, denticles or prominent protrusions. Labrum concealed. Apical tentorial pits small. Eyes with inner orbits parallel to each other, without setae, height 0.87 × head height in lateral view. Ocelli normal sized. Occipital carina visible ventrally. Genae rather narrow, seems smooth. Antennae at least 5.4 mm, with about 33 segments; more or less evenly thick throughout; scape 1.4 × longer than wide, larger than pedicle; first antennal segment length about 2.8–3.6 × apical width; other antennal segment lengths between 1.7 and 1.4 × apical width.

Mesosoma. Pronotum moderately long, slightly deeper than long. Propleuron without lobe. Mesoscutum finely or coarsely punctate, appears evenly pubescent; carina along lateral margin complete to anterior end of scutellum; notaulus distinct, extends to half-length of mesoscutum, converging and meeting other notaulus in middle. Mesopleuron convex; epicnemical carina not curving anteriorly, extends to about lower third of pronotum; sternaulus absent; mesopleural furrow slightly angled opposite episternal scrobe. Mesosternum appears transverse in front of fore coxa; posterior transverse carina present at least laterally and between mid coxae. Metapleuron about 1.5–1.7 × as long as deep; submetapleural carina complete, anterior section unmodified; pleural carina present as distinct carina along whole length; juxtacoxal carina present. Propodeum rounded laterally, about as long as wide, hind margin simple; lateromedian and lateral longitudinal carinae present; anterior and posterior transverse carina complete, carina leading from pleural carina to spiracle present; spiracle shape or position unclear, without modifications. Dorsal part of metacoxal cavity appears to be just at or only slightly above lower margin of metasomal foramen magnum.

Fore leg tibia with 4th tarsomere longer than wide; trochantellus differentiated from femur. Mid leg with two spurs on tibia, spurs equal in length; trochantellus differentiated from femur. Hind leg with coxa 1.2 × longer than deep; femur 2.5 × longer than wide, without modification; tibia slightly enlarged, with two tibial spurs, equal in length; 1st tarsomere 3.5 × longer than apically wide. Claws appear large, simple, with arolium enlarged, projecting conspicuously beyond apex of claw.

Wings. Fore wing 4.4 mm, with areolet appearing closed, shape unclear; 2m-cu present, shape appears slightly bowed outwards; 4Rs sinusoidal; 1cu-a interstitial to 1M + 1Rs; 1m-cu&2Rs + M vein angled; pterostigma 3.8 × longer than wide, 0.6 × 1 R 1; cell 2 R 1 3 ×longer as wide; 5M tubular throughout or partly spectral; 2Cu same length as 1M + 1Rs; 1cu-a 0.45×1M+1Rs; 2Cu 2.8 × longer than wide; 3Cu longer than 2cu-a; 4Cu and 5Cu same length; 2A 2.4 × longer than 1cu-a. Hind wing with 1Cu slightly shorter than cu-a; 2Rs, 2M and 2Cu tubular or partly spectral; 1Rs 1.85 × rs-m; eight distal hamuli.

Metasoma. 3.1 mm, cylindrical. T 1 finely punctate, 1.2 × longer than posteriorly wide, with stout base, in dorsal view parallel sided, in lateral view with anterior small hump; dorso-lateral carina more or less absent, vestige at anterior and posterior ends; spiracle at 0.44 × T 1; glymma present; latero-median carina along whole length, slightly converging before becoming parallel after first third; laterotergite triangular along almost entire length and membranous; S1 length 0.44 × T 1. T 1 and T 2 separated by normal joint. T 2 transverse, with deep to fine punctures, laterally 0.7 × length of T 1; latero-median carina might be present anteriorly, but uncertain; laterotergite creased, broad, 0.46 × as wide as long; spiracle above crease. T 2- T 4 with latero-median round swellings and subapical transverse impressions. T 3 and T 4 with laterotergite creased, broad, about 0.5 × as wide as long. T 6 and T 7 of similar size. Aedeagus appears dorsoventrally depressed. Parameres enlarged, longer than most tergites laterally; about 1.5 × as long as wide at mid length.

Diagnosis: See genus diagnosis.

Figures

Fig. 7 Holotype of Firkantus freddykruegeri gen. et sp. nov. A Habitus of specimen,lateral view. B Anterior view of face,right side with facial structures indicated. C Fore wing with folds indicating wing venation. D Anterior part of metasoma, dorsal view. E Posterior part of metasoma, with parameters and aedeagus. F Interpretative drawing with an additional drawing of the propodeum and T1 in dorsal view,where photos and micro-CT scan were used as templates.Scale bar A: 1 mm, B: 0.5 mm, F: lower 1 mm, right 0.5 mm