Albunea: Beschin and De Angeli, 1984: 97–102

BOYKO, CHRISTOPHER B., 2002, A Worldwide Revision Of The Recent And Fossil Sand Crabs Of The Albuneidae Stimpson And Blepharipodidae, New Family (Crustacea: Decapoda: Anomura: Hippoidea), Bulletin of the American Museum of Natural History 2002 (272), pp. 1-396 : 221-222

Albunea: Beschin and De Angeli, 1984: 97–102

(part). – De Angeli, 1998: 19–20 (not Albunea

Weber, 1795).

DIAGNOSIS: Carapace anterior margin narrow with low rounded spine; median setal field triangular and projecting. Rostrum small, large spines lateral to ocular sinus absent. CGs well defined, not diffuse; CG1 entire, CG6 and CG7 fused; CG5 and CG11 absent. Posterolateral margin of epibranchial region produced into bulge. Branchial region with numerous transverse setae. Posterior submarginal groove not reaching margin of posterior concavity. Pereopod I dactylus dorsal margin smooth.

DISTRIBUTION: Known only from Middle Eocene fossil material from Italy.

TYPE SPECIES: Albunea lutetiana Beschin and De Angeli, 1984 , by monotypy.

ETYMOLOGY: The genus name is a composite of the Latinized name of the country where the only specimens have been found combined with the name of the type genus of the family. The gender is feminine.

REMARKS: This genus is intermediate between Squillalbunea and Stemonopa .

Italialbunea lutetiana (Beschin and De Angeli, 1984) , new combination Figure 72

Albunea lutetiana Beschin and De Angeli, 1984: 99–102 , pl. 1, figs. 2, 2a, pl. 2, figs. 2–3a*.— De Anglei, 1998: 19–20, figs. 1a, b, pl. 1, figs. 1–4.

MATERIAL EXAMINED: Italy: Middle Eocene, Valle del Chiampo, Eastern Lessini, coll. unknown: 1 carapace, 23.6 mm cl, holotype (calco­mold of MCSNV 10440).

DIAGNOSIS: As for genus.

DESCRIPTION: Carapace (fig. 72A) wider than long. Anterior margin slightly concave on either side of ocular sinus, becoming convex laterally, unarmed. Rostrum small, rounded. Ocular sinus smoothly concave and unarmed. Frontal region smooth (or with only few low rounded teeth); setal field narrow anteriorly and posteriorly; medial portion produced into triangular peak; posterior lateral elements reduced to narrow bands of setae. CG1 parallel to anterior margin of carapace, nearly straight, strongly crenulate, medial fragment and curved posterior lateral elements united. Mesogastric region smooth; CG2 present as two to four very short medial elements; CG3 broken into two short elements and two long elements between posterior lateral elements of CG1; CG4 with two short, anteriorly displaced, medial elements and two longer lateral elements between longer supralateral elements. Hepatic region smooth, with oblique setose groove at median of lateral margin. Epibranchial region generally triangular, smooth. Metagastric region smooth; CG5 absent. CG6 strongly crenulate, strongly anteriorly concave medially and sloping out to separated, anteriorly convex lateral thirds. CG7 oblique, united with medial element of CG6. Cardiac region smooth; CG8 present as several very short elements. CG9 present as two short lateral grooves with large gap at midline. CG10 present as two long lateral elements, with gap between fragments. CG11 absent. Post­CG11 element absent. Posterior submarginal groove not reaching margin of posterior concavity.

Pereopod I (fig. 72B) dactylus curved and tapering; lateral and mesial surfaces smooth. Propodal lateral surface with numerous short, transverse rows of strong rugae; dorsal margin unarmed; ventral margin distally produced into acute spine; cutting edge lacking teeth. Carpus with dorsodistal angle unarmed (but drawn with sharp dorsodistal spine in De Angeli [1998]), transverse ridges on distal two­thirds of dorsolateral and ventrolateral margins.

DISTRIBUTION: Known from the Middle Eocene from Valle del Chiampo, Eastern Lessini, as well as Cava ‘‘main’’ di Arzignano, Cava ‘‘Albanello’’ di Nogarole Vicentino, and Cava di Alonte, Italy ( De Angeli, 1998: 19).

TYPE SPECIMENS: MCSNV 10440 (holotype), De Angeli Collection (paratype), Beschin Collection (paratype).

TYPE LOCALITY: Middle Eocene, Valle del Chiampo, Eastern Lessini, Italy.

REMARKS: This species possesses a number of unique morphological characters, in spite of its being known only from fossil carapace and pereopod I material. The narrow anterior carapace margin is reminiscent of Zygopa and Squillalbunea , and it shares an overall carapace shape and small but present rostrum with Squillalbunea as well. The anterior margin of the carapace is armed with low round­ ed spines (not with sharp spines as on other species of Albunea , as drawn by Beschin and De Angeli [1984]); such spines are also found in Squillalbunea . It differs from Squillalbunea in that it has well­defined carapace grooves instead of a diffuse setal pattern, and Italialbunea lutetiana does not appear to have a toothed dorsal margin of the pereopod I dactylus. The pattern of carapace grooves is very similar to those seen in the genus Stemonopa , with which it also shares fused anterior and posterior elements of CG1. Based on the above characters, this taxon must be removed from Albunea sensu stricto. It cannot, however, be placed in either Squillalbunea or Stemonopa , as it has unique character combinations not found in either of those genera. Therefore, it is here placed in its own monotypic genus.

Figures

Fig. 72. Italialbunea lutetiana (Beschin and De Angeli, 1984), n. comb.: A, 23.6 mm cl, MCSNV 10440, holotype; B, MCSNV, paratype. A. Carapace, dorsal view. B. Right pereopod I dactylus, propodus, and carpus, lateral view. Scale = 8.5 mm.