Berothidae

Wedmann, Sonja, Makarkin, Vladimir N., Weiterschan, Thomas & Hörnschemeyer, Thomas, 2013, First fossil larvae of Berothidae (Neuroptera) from Baltic amber, with notes on the biology and termitophily of the family, Zootaxa 3716 (2), pp. 236-258 : 238-240

Berothidae indet., larva A

Figs. 1 , 2

Material examined. Specimen No. 240 in the private collection of Thomas Weiterschan (Höchst Odw, Germany); a first instar larva in a relatively small piece of Baltic amber (precise collecting locality is unknown).

Description. Larva 1.83 mm long (including mouthparts), rather slender.

Head capsule elongated, 0.24 mm long, 0.16 mm wide (length/width ratio 1.5). Ocular areas present laterally, extending outwards from antennal sockets; stemmata (= convex corneae, lenses) not distinctly visible, possibly one on each side. Dorsally, ecdysial cleavage lines distinct, consisting of frontal, lateral and coronal sutures. Two anterior arms of frontal suture converging slightly for nearly two thirds of head capsule length, from inner margin of antennal tubercles to lateral sutures; posterior arms of frontal suture (after joining lateral suture) strongly convergent until they touch. Lateral sutures straight, reaching lateral margins of head (in dorsal view), inclined slightly to anterior part of frontal sutures at nearly right angle. Coronal suture rather short. Ventrally, coxopodites of maxillae (stipes and cardo) and labium clearly visible. Stipes and cardo relatively narrow; boundary between them not clearly visible. Labium composed of prementum (= prelabium) and postmentum (= postlabium). Prementum short and relatively narrow; anteriorly excised; postmentum long and broad, trapezoid in shape.

Mandibles apically pointed. Maxillary blades very broad basally (about 0.05 mm), gradually narrowing apically; closely associated with mandibles to form mandibulomaxillary stilets, 0.22 mm long.

Antennal sockets located on relatively high projections (=antennal tubercle of MacLeod (1964)). Antennae three-segmented, 0.32 mm long; basal segment slightly conical, 0.04 mm long, 0.02 mm wide; second segment long and clearly annulated, 0.12 mm long, 0.02 mm wide; third segment long and thin, 0.08 mm long, about 0.01 mm wide, bearing fine, feebly visible apical seta, 0.08 mm long.

Labial palps slightly longer than mandibles, 4-segmented. Basal segment cylindrical, 0.03 mm long, 0.02 mm wide. Second segment elongate, 0.1 mm long and slightly wider than basal one, widest at 2/3 of its length; annulation clearly visible. Third segment 0.03 mm long, slender (half as wide as second). Fourth segment not clearly separated from third, 0.06 mm long and slightly thinner than third, gradually narrowing towards pointed apex.

Cervix 0.12 mm wide, retracted into prothorax; visible length 0.08 mm ventrally, not visible dorsally.

Prothorax 0.18 mm long, 0.17 mm wide; two large dorsal sclerites indistinctly visible. Mesothorax 0.13 mm long, 0.19 mm wide; metathorax 0.12 mm long, 0.19 mm wide; both with indistinctly visible paired oval dorsal sclerites.

Legs rather short, robust: coxa relatively long and narrow; trochanter relatively small; femur narrowed distally; tibia narrow, tibia and tarsus nearly equal in length; pretarsus short bearing two short claws and long, trumpetshaped empodium. Forelegs 0.28 mm long (if stretched out).

Abdomen divided into 10 clearly separated segments, nine of which with lateral lobes. Segments 1 to 6 gradually increasing in length from 0.09 mm to 0.12 mm, their width gradually decreasing from 0.21 mm to 0.18 mm. Segments 7 to 9 gradually decreasing in length from 0.1 mm to 0.06 mm and in width from 0.18 mm to 0.11 mm. Segment 10 slightly conical (0.07 mm long, maximum 0.07 mm wide), rounded posteriorly, without lateral lobes and appendices.

Remarks. Based on its size, the larva is considered a first instar.

Figures

FIGURE 1. Berothidae indet., larva A, whole larva as preserved. A, photograph. B, drawing (both dorsal view). Scale bar is 0.5 mm.

FIGURE 2. Berothidae indet., larva A. A – D, head in dorsal (A, C) and ventral view (B, D). E, foreleg, ventral view. an, antenna; cd, cardo; cvx, cervix; cs, coronal suture; cx, coxa; em, empodium; fm, femur; fs, frontal suture; lp, labial palpus; ls, lateral suture; md, mandible; mx, maxillary blade; prm, prementum; psm, postmentum; pt, pretarsus; st, stipes; tb, tibia; tr, trochanter; ts, tarsus. Scale bars are 0.25 mm (A, B), 0.1 mm (C – E).