Sayrevilleus, GRIMALDII GRATSHEV & ZHERIKHIN, 2000

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 : 777-779

SAYREVILLEUS GRIMALDII GRATSHEV & ZHERIKHIN NEW PLACEMENT ( FIGS 1–10 ; FOR 3D MODEL OF THORAX AND HEAD SEE FIG. S1 )

Sayrevilleus grimaldii Gratshev & Zherikhin, 2000: 245–246 , fig. 1.

Sanyrevilleus grimaldii: Legalov, 2003: 85, 2007: 31 ; 2009: 292; 2010: 94.

Holotype: Figures 6–7 . New Jersey Amber: Late Cretaceous; New Jersey: Middlesex Co., Sayreville, Sunrise Landing, viii.-xi.1993; AMNH no. NJ-89; Gerard R. Case coll. ( AMNH). The amber piece ( Fig. 1 ) is cut, polished, and embedded in a thin block of synthetic resin. It can easily be examined laterally; the other thin, unpolished sides obstruct a dorsal, ventral, or apical view by light microscopy. The right side is relatively clear but the left side extensively obscured by minute bubbles. Extensive cracks in the amber obscure the specimen; it is possible that some of these structures derive from a spider web, as suggested by Gratshev & Zherikhin (2000). No dirt or debris are detectable on the surface of the beetle, as noted in the original description. However, the entire surface of the specimen including smooth surfaces (such as the rostrum or the side parts of the abdominal ventrites) has a cracked reticulated structure, resembling dried mud. This artefact probably occurred during carbonization of the specimen. Some characters, such as the fine sculpture and striation of the elytra or a possible crenulation of the tibiae, were destroyed in the process. It is therefore impossible to judge if the elytral punctation is striate or confused, as claimed by Gratshev & Zherikhin (2000). Setae are poorly preserved where visible on the inner edge of the tibiae; it is likely that the specimen was more or less densely setose, but no setae can be clearly seen and distinguished from fissures. The shape of the pronotum is artificially asymmetrical, probably as a result of lateral pressure. The apex of the rostrum (mouthparts) on the left side is damaged, probably cut off during the original preparation. The right foreleg and the right hindleg are missing. The right elytron is slightly lifted.

Redescription: Total length from elytral apex to base of rostrum c. 2.1 mm. Head including rostrum 0.69 mm long. Eyes lateral, large, subrotund, c. 0.19 mm in diameter, protruding, coarsely facetted, the ommatidia distinctly convex. Eyes medially well separated by slightly less than minimum width of rostrum (0.9 ¥) dorsally; ventrally more widely separated. Forehead (as in Figs 7, 9 ) with pair of sulci bordering eyes, median subtrapezoid area elevated. Rostrum subcylindrical, weakly curved, length distinctly shorter than pronotum (in lateral aspect 0.67 mm long); basally with scrobes from antennal insertions to eyes. Mouthparts in apical 0.30 of rostrum. Right mandible ( Figs 7, 9–10 ) elongate, stout, exodont, subapically with two blunt teeth on outer edge; apically pointed. Labial palps with three articles. Maxillary palps with at least three, probably more articles (uncertainty caused by transverse cracks in maxilla, impossible to distinguish from true joints between articles; Fig. 10 ). Antenna. Length of club 0.18 mm. Insertion dorsolaterally in basal 1/6 of rostrum, 0.11 mm from base; nongeniculate; scape hardly or just reaching anterior margin of eye; article 1 of funicle swollen; article 7 globiform. Antennal club distinct, somewhat loose, about 1.5 ¥ wider than funicle. Terminal article of club 1.5 ¥ longer than wide. Prothorax. Length 0.78 mm; notosternal suture difficult to define on left side, open on right side; apical edge of pronotum continued ventrally to form a rounded extension, delimited by marked constriction in front of procoxa. Procoxa subconical, prominent. Prosternum in front of procoxae short. Prosternellum and hypomeral lobes behind procoxae distinct, not fused. Elytra. Length 1.62 mm; lateral margin above dorsoanterior angle of metanepisternum with indentation. Metanepisternum subparallel, c. 4.6 ¥ longer than wide; abdominal ventrite 1 and metanepisternum broadly joining above metacoxa. Legs. Tibiae straight, slender. Protibia relatively long, 0.62 mm. Mesotibia (0.50 mm) shorter (0.83 ¥) than mesofemur (0.60 mm). Metatibia (0.55 mm) shorter (0.85 ¥) than metafemur (0.65 mm). Tarsi. Tarsomere 1 of protarsus ( Fig. 4 ) 0.17 mm, c. 3 ¥ longer than wide; tarsomere 2 of protarsus 0.12 mm long, apically subtruncate, weakly concave, not deeply excised; tarsomere 3 of protarsus c. 0.10 mm long, c. 1.3 ¥ longer than wide; onychium of protarsus 0.15 mm long; claws divaricate, simple. Thoracic venter. Mesocoxae separated by posterior process of mesoventrite and anterior process of metaventrite meeting near mesocoxal mid-level. Metaventrite impunctate, midline impressed. Abdomen ( Fig. 5 ). Ventrites at same level; ventrites 1–2 subequal in length, slightly longer than ventrites 3–5; sutures between ventrites distinct; side parts of ventrites opposing elytra folded dorsad.

Note: The preservation of the unique specimen is less than optimal; thus, the description of Sayrevilleus will remain fragmentary until additional specimens become available.

Figures

Figures 1–10. Sayrevilleus grimaldii, holotype: 1, cut amber, in a block of synthetic resin; 2, habitus; left side; 3, habitus; right side; 4, legs; arrows mark simple claws; numbers mark articles of right protarsus; 5, right side of thorax and abdomen; arrow marking side parts of abdominal ventrites; note cracked surface; 6, arrows marking teeth of right mandible; 7–9, volume rendering of synchrotron microtomography of head and thorax; 10, mouthparts: right side; ventrolateral aspect. Abbreviations: Lp, labial palp; Md, mandible; Mxp, maxillary palp; Pr, prementum.