Grandoculus chemahawinensis, Penney, 2004

Penney, David, 2004, Cretaceous Canadian amber spider and the palpimanoidean nature of lagonomegopids, Acta Palaeontologica Polonica 49 (4), pp. 579-584 : 582

Grandoculus chemahawinensis sp. nov.

Figs. 1 , 2 .

Holotype and only known specimen: MCZ A 5000 , juvenile (or female), Canadian amber, Manitoba, Cedar Lake ; coll. Carpenter.

Type horizon and locality: Fossil in amber from Cedar Lake, Manitoba, Canada; mid−Campanian (76.5–79.5 Ma), Upper Cretaceous.

Derivation of the name: The specific epithet is after the Chemahawin Indian Reservation at Cedar Lake, in recognition of the Indian who presented a piece of amber to W.C. King in 1890 and thus sparked an interest in this amber deposit.

Diagnosis.—As for the genus.

Description.—Juvenile (or female). Body length approximately 4.6; carapace length approximately 2.3, width 1.6, 1.1 high in the cephalic region which is swollen anterolaterally; covered with a pubescense of fine setae and with stronger, erect setae dorsally and on the clypeus; fovea, if present, not visible. Only two eyes are visible, on the left hand side of the carapace ( Figs. 1 , 2 ), the right side lies at the surface of the amber and has been ground away during the preparation process prior to receipt by the author ( Figs. 1 , 2 ). The uppermost eye is particularly large with a diameter of 0.4, the eye situated below it is much smaller ( Figs. 1 , 2 ); thus the spider had at least four eyes. The chelicerae are relatively long (1.1), procurved ( Figs. 1 , 2 ), covered with long, stiff setae and lack stridulatory ridges; the presence or absence of peg−teeth or true cheliceral dentition is unclear, however a peg−tooth may be visible on the left chelicera when the specimen is viewed from the left side using transmitted light. The sternum and mouthparts are not clearly visible but the maxillae are longer than wide and with serrula distally ( Fig. 2 ). The opisthosoma has been compressed but is approximately 2.3 long and appears unmodified and covered with fine setae; spinnerets not visible.

Much damage has been caused to the legs during preparation of this specimen prior to receipt by the author, and the only two that remain in their entirety are left leg 1 and left leg 3. Leg formula probably 1234 or 1243; leg 1 distinctly more robust than the others. femur 1.7, patella 0.9, tibia 1.6, metatarsus and tarsus not measurable, but with very closely packed, long, hook−tipped scopular hairs on the prolateral surface of the metatarsus ( Fig. 2 ), and long, straight, pointed scopular hairs on the prolateral surface of the tarsus ( Fig. 2 ). Leg 2 patella 0.6, tibia 1.3 with short scopulae along most of its length ( Fig. 2 ). Leg 3 patella 0.5, tibia 0.9, metatarsus 0.8, tarsus 0.6. The only claws visible are on left tarsus 1 and left tarsus 3 and appear to be two in number, however, an inferior claw may just be visible behind the left superior claw on tarsus 3; superior claws appear to lack teeth, but these are not visible in lateral view and the teeth may be hidden. All legs lack spines and are covered with fine, feathery setae; a single trichobothrium is visible on metatarsus 1 ( Fig. 2 ). The only true spines occur on the femora, patellae and tibiae of the pedipalps, the palpal tarsus lacks a terminal claw and has long, thick setae ventrally ( Fig. 2 ).

Figures

Fig. 1. Grandoculus chemahawinensis gen. et sp. nov., holotype MCZ A 5000, juvenile, Canadian amber. A. Dorsolateral view. B. Ventrolateral view. Scale bar 1.0 mm.

Fig. 2. Grandoculus chemahawinensis gen. et sp. nov., holotype MCZ A 5000, juvenile, Canadian amber. A. Dorsolateral view. B. Ventrolateral view, showing structure of hook−tipped scopular hair. Scale bar 1.0 mm.