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Journal of Paleontology 92(3):466–477
spectrometry (X-EDS). These analyses were performed on C-coated (1) fragments of the crabs, (2) polished thin sections of the nodule matrix, and (3) sampled modern gills. The mineral- ogy of the matrix was investigated by X-ray diffractometry (XRD) on tiny fragments of the nodule MNHN.F.A59114 (respectively, brown friable outermost layer and gray innermost rock). These fragments were crushed in an agate mortar; the resulting powder was dispersed in alcohol and the solution dried on a zero diffraction plate before measurement. XRD analyses were performed using a Bruker D2 PHASER operating at the MNHN (Paris, France) with a Lynxeye detector (opening: 5.821° 2Theta) and a Ni-filtered Cu Kα radiation (30 kV, 10mA) with a 0.02° 2Theta step width.
Repositories and institutional abbreviations.—Types, figured, and the other 109 specimens examined in this study are depos- ited in the following institutions: Collection de Paléontologie (MNHN.F) and Collection de Zoologie (MNHN.IU) of the Muséum national d’Histoire naturelle, Paris, France.
Systematic paleontology
Anatomical abbreviations.—CL, carapace length (inclusive of rostrum); CW, carapace width (including lateral spines); FM, frontal margin width; OFM, orbitofrontal margin width; PM, posterior margin width.
Decapoda Latreille, 1802
Pleocyemata Burkenroad, 1963 Brachyura Latreille, 1802
Eubrachyura Saint Laurent, 1980 Heterotremata Guinot, 1977 Cancroidea Latreille, 1802 Cancridae Latreille, 1802
Genus Romaleon Gistel, 1848
Type species.—Corystes (Trichocera) gibbosula De Haan, 1833 by monotypy.
Other species.—Romaleon antennarium (Stimpson, 1856), as Cancer, Pliocene–Pleistocene, extant, west coast North America; R. branneri (Rathbun, 1926) as Cancer, Pliocene– Pleistocene, extant, west coast North America; R. dereki Nations, 1975, as Cancer (Romaleon), middle Miocene, California, USA; R. gibbosulum (De Haan, 1833,), as Corystes (Trichocera), extant, Japan; R. granti (Rathbun, 1932), as Cancer, Pliocene–Pleistocene, west coast North America; R. jordani (Rathbun, 1900), as Cancer, Pliocene–Pleistocene, extant, west coast North America; R. nadaensis (Sakai, 1969), as Cancer, extant, Taïwan to Japan; R. luzonensis (Sakai, 1983), as Cancer, extant, Philippines; R. nakagawaensis Kato and Hikida, 2002, as Romaleon, middle Miocene, Japan; R. parspinosus Casadío et al., 2005, as Romaleon, lower upperMiocene, Eastern Argentina; R. setosum (Molina, 1782), as Cancer, Pliocene– Pleistocene, west coast North America, extant, west coast South America; R. sakamotoi (Kato, 1996), as Cancer,middle Miocene, Japan; R. sanbonsugii (Imaizumi, 1962), as Cancer, middle Miocene, Japan; R. urbanus (Rathbun, 1917), as
Cancer, Pliocene, California; R. yanceyi (Nations, 1975), as Cancer, Pliocene–Pleistocene, west coast North America.
Diagnosis.—Carapace moderately areolate, preserved cuticle with small granules located primarily but not exclusively on swollen regions. Front moderately advanced, projected beyond orbits, with five frontal teeth, median three clustered, pointed median tooth. Anterolateral margin with nine singular teeth, sharply triangular, curving forward, lined with granules; first tooth (outer orbital corner) pointed. Posterolateral margins weakly concave, with single tooth anteriorly. Chelipeds with sharp spines or granules on the outer and upper surfaces of the carpus and propodus.
Remarks.—Emended diagnosis modified from Nations, 1975 and from Schweitzer and Feldmann, 2000.
Romaleon franciscae Van Bakel, Robin, and Noël new species Figure 2
Types.—Holotype: MNHN.F.A59107 (complete carapace; L=16mm, W=38mm), paratypes: MNHN.F.A59108 (com- plete carapace; CL=14mm, CW=21mm), MNHN.F.A59109 (nearly complete carapace, front teeth and orbits; CL=11mm, CW= 14mm), MNHN.F.A59110 (preserved endoskeleton; CL=10mm, CW=13.5mm),MNHN.F.A59111 (complete car- apace; CL=11mm,CW=15mm), MNHN.F.A59112 (cheliped: dactylus+propodus and imprint), MNHN.F.A59113 (cheliped: carpus+right propoduswith tubercles on top),MNHN.F.A59114 (smallest cheliped: left carpus+propodus).
Type locality.—Miocene of the Kerguelen Islands, Prince of Wales foreland, Cap Milon, (49°26'57''S, 70°23'04''E).
Diagnosis.—Carapace wider than long (CL/CW ratio 0.66–0.85), gently convex in longitudinal and transverse cross- sections; front tridentate, median tooth smaller; orbit with two distinct notches, anterolateral margin with nine triangular teeth with teeth 4–9 grouped in clusters of two; a tenth reduced tooth on the posterolateral margin; chelipeds massive, tubercular on upper margin of propodus, palm with four equidistant blunt crests.
Description.—Crab of moderate size, carapace width 13–48mm (n=35 measurable carapaces). Holotype ratios: OFM 47% of theCW; CL 73% of theCW; FM(inner orbital corners) 22% of the CW; PM 38% of the CW. Carapace oval, wider than long, ratio width to length 1.2–1.5. Carapace gently convex in longitudinal and transverse cross-sections, weakly defined grooves delineating gastric, cardiac, and branchial regions; regions moderately marked, more inflated at protogastric, epibranchial, and cardiac regions; hepatic, intestinal, and bran- chial areas less inflated. Orbitofrontal margin conspicuously wide for the genus and family, occupying 47% of maximum carapace width. Front (excluding inner orbital corners) narrow, horizontal, weakly produced, tridentate, the base of the inter- dental space practically arriving at the orbital line of the two inner orbital corners; axial tooth considerably smaller, slightly more projected, and more depressed than lateral teeth; all teeth
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