Baltocar undetermined

Riedel, Alexander, Rolo, Tomy Dos Santos, Cecilia, Angelica & Kamp, Thomas Van De, 2012, Sayrevilleinae Legalov, a newly recognised subfamily of fossil weevils (Coleoptera, Curculionoidea, Attelabidae) and the use of synchrotron microtomography to examine inclusions in amber, Zoological Journal of the Linnean Society 165 (4), pp. 773-794 : 786-789

BALTOCAR SUBNUDUS RIEDEL SP. NOV.

( FIGS 49–58 )

Differential diagnosis: Body subglabrous, without or with indistinct pubescence. Rostrum relatively short and markedly curved. Elytra densely, somewhat irregularly punctate. Tarsi with onychium 0.7–1.1 ¥ longer than tarsomere 1.

Holotype: Collected at Jantarny (Palmnicken) near Kaliningrad. HCH 884 to be deposited in SDEI. ( Figs 49–53 ). The amber is neatly cut around the inclusion and embedded in GTS polyester resin of Vosschemie, a material with a diffraction index very

63 64

close to amber ( Hoffeins, 2001) ( Fig. 56 ). The inclusion can be observed from six sides, but is tilted to the left, complicating some measurements. A crest of cracks exists around the specimen. Judging from the slightly projecting rim of tergite VIII, the specimen is probably a male.

Paratypes: Baltic amber, collected at Jantarny near Kaliningrad. CGCG 7977 . ( Figs 54–55, 57–58 ). The small piece of clear amber ( Fig. 57 ) is polished and coated. The inclusion is tilted to the side and can be observed from the dorsolateral and ventrolateral aspects. There is a crack along the median plane. The specimen is a female with the ovipositor protruded .

Description of holotype: (Data referring to female paratype are given in parentheses.) Total length from elytral apex to base of rostrum c. 2.5 mm (2.3 mm). Head including rostrum 1.03 mm (0.88 mm) long. Eyes large, protruding, subrotund, 0.22 mm (0.18 mm) in diameter; coarsely facetted, the individual ommatidia distinctly convex. Eyes dorsally well separated by about minimum width of rostrum. Forehead between eyes with deep median furrow (appearing flat); laterally with subtriangular callus bordering eye; this callus with few punctures, without setae (apparently without such callus); behind eye punctate, posteriorly with transverse striation. Rostrum in lateral view subcylindrical, markedly curved, shorter (0.73 ¥) than pronotum (1.1 ¥ longer than pronotum); in lateral aspect 0.55 mm (0.55 mm) long; surface subglabrous, with sparse minute punctures. Mouthparts in apical 0.24 (0.22) of rostrum. Epistome medially with incision, without visible setae. Mandibles opened, thin, three teeth on outer edge; second tooth below cavity on dorsal surface; inner edge evenly convex to tip of apical outer tooth; mandible lodged in deep socket, distinctly projecting beyond rostral apex. Antenna. Total length 0.81 mm (0.91 mm), length of club 0.26 mm (0.33 mm). Insertion sublaterally in basal 1/6 of rostrum; nongeniculate; scape reaching anterior margin of eye; article 1 of funicle somewhat swollen, shorter (0.7 ¥) than (subequal to) scape; article 2 of funicle more slender, c. 3.5 ¥ longer than wide; articles 3–7 of funicle decreasing in length, width subequal, article 7 subovate, c. 1.3 ¥ longer than wide. Antennal club distinct, somewhat loose, about 2 ¥ (3 ¥) as wide as funicle; sparsely setose; terminal article of club 1.8 ¥ (2.0 ¥) longer than wide. Prothorax. Length 0.81 mm (0.50 mm), width basally 0.63 mm, apically 0.55 mm; without subapical or sub-basal constriction; disc coriaceous with interspersed minute punctures, nude; ventrally short, 0.26 mm, in front of procoxa very short, less than half as long as behind it; notosternal suture open, straight, directed vertically, approxi- mately in line with axis of procoxa; seemingly continued by approximately V-shaped wrinkle; its upper branch leading towards shallow constriction in front of procoxa. Procoxa subconical, strongly prominent. Scutellum subtrapezoid, subglabrous. Elytra. Length 1.76 mm (1.76 mm); maximal width in apical third 1.28 mm (1.14 mm), between humeri 0.94 mm (0.90 mm); punctures coarse, interspaces between them about as wide as their diameter, partly arranged in rows, but pattern of striae largely obscured by interspersed punctures; with hardly visible sparse vestiture of subrecumbent thin setae (striae and intervals each with c. one row of recumbent setae). Epipleuron mesially delimited by ridge; posteriorly weakly irregularly sculptured, anteriorly glabrous. Meso- and metathorax subglabrous, laterally punctate, metathorax anteriorly with row of punctures. Mesocoxal cavities laterally open, process of mesoventrite not meeting metaventrite. Metanepisternum with dorsoanterior process fitting into indentation of elytral margin; posteriorly narrowing, in front of metacoxa its width c. 0.11 ¥ its total length; posteriorly extending over metacoxa, and overlapping abdominal ventrite 1, separating metacoxa from elytral margin. Metaventrite convex, in posterior half midline impressed. Legs. Tibiae straight, slen- der. Protibia (0.72 mm) (0.78 mm) 1.26 ¥ (1.30 ¥) longer than profemur (0.57 mm) (0.60 mm); mesotibia (0.62 mm) (0.70 mm) 1.19 ¥ (1.11 ¥) longer than mesofemur (0.52 mm) (0.63 mm); metatibia (0.61 mm) (0.61 mm) shorter (0.86 ¥) (1.07 ¥ longer) than metafemur (0.71 mm) (0.57). Tibial crenulation not visible, possibly indistinct (without tibial crenulation). Tibial spurs not visible, possibly indistinct. Tarsi. Length and structure of protarsus, mesotarsus, and metatarsus identical; length c. 0.55 mm each. Tarsomere 1 of protarsus 0.20 mm (0.20 mm) long, c. 3 ¥ longer than wide; tarsomere 2 of protarsus 0.14 mm (0.12 mm) long, c. 3.0 ¥ longer than wide, apically truncate and not deeply excised; tarsomere 3 of protarsus c. 0.11 mm (0.09 mm), c. 1.3 ¥ longer than wide; onychium of protarsus 0.21 mm (0.13 mm) long; insertion of onychium in centre of tarsomere 3, distance of cavity to tarsal edge basally and laterally subequal. Claws divaricate, simple. Abdomen. Abdominal ventrite 1 with concave margin bordering metacoxa, laterally subequal to ventrite 2, at level of femoral articulation shorter (0.75 ¥); following ventrites successively decreasing in length; ventrites 1–3 subglabrous, ventrites 4 and 5 more densely punctate; segment VIII somewhat projecting, but largely concealed by cracks in the amber.

Notes: The male holotype and the female paratype agree in general body form: the curved shape of the short rostrum, and the sparse to nearly absent pubescence. The different lengths of the tarsal onychium and the structure of the forehead could indicate that they represent distinct species; however, the cracks in the amber enclosing the paratype preclude an unequivocal description of its forehead, and the different lengths of the onychium may be a sexually dimorphic character. Additional data would be needed to clarify the specific status of the paratype.

Figures

Figures 49–58. Baltocar subnudus Riedel sp. nov., 49–53, 57: male paratype; 54–56, 58: female paratype. 49, left side; 50, right side; 51, left side of elytra; 52, frontal aspect of head; 53, thorax and head; note open notosternal suture and curved rostrum; 54, left side; 55, ventrolateral aspect of right side; 56, amber piece with inclusion of holotype; 57, amber piece with inclusion of paratype; 58, ventrolateral aspect of prothorax and head.