Ranina ” burleighensis, Holland & Cvancara, 1958

Pasini, Giovanni & Garassino, Alessandro, 2017, A preliminary review of the fossil species of Ranina Lamarck, 1801 (Decapoda, Brachyura, Raninidae), with systematic remarks, Natural History Sciences 4 (1), pp. 43-72 : 69

“ Ranina ” burleighensis Holland in Holland & Cvancara, 1958

Fig. 20

Ranina? burleighensis Holland in Holland & Cvancara, 1958: 504, 505, fig. 3c, Pl. 74, fig. 15.

Ranina burleighensis - Schweitzer et al. 2010: 74. – De Angeli & Beschin 2011: 13. – Karasawa et al. 2014: 260.

Type material: holotype, USNM 562094 .

Type locality: South of Moffit , Burleigh County, North Dakota, USA .

Geological age: Cannonball Formation, Paleocene.

Examined material: holotype.

Description by Holland & Cvancara (1958): “ The holotype consists of the broken distal portion (twothirds?) of the left manus, the stub of the pollex or immovable finger, and the proximal part of the dactylus of a rather large propodus; the ma us, though laterally crushed, appears to have been oblong in cross-section with the width about three-fourths the height; the outer surface of the manus is covered with irregular spaced, asymmetrical tubercles which are inclined forward; between the tubercles are smaller, more symmetrical, rounded granules; inner surface similar but with the tubercles less pronounced; the tubercles apparently disappear toward the upper surface and on the pollex; on upper distal corners of the manus near the articulation of the dactylus is situated a pair of spine bases; the base of a single, small, forward-directed spine can still be seen on the outer surface near the junction with the pollex; the dactylus is so broken that it is impossible to determine its length; on the inferior surface a rounded projection appears near the break, 6.5 mm anterior to the junction with the manus; this projection is presumed to be the first prehensile tooth; at this place the dactylus is subovate but it expands rapidly in a proximal direction and becomes flatter on the superior surface; posteriorly directed projections occur on the upper proximal corners of the dactylus; the projections apparently articulated with poorly preserved sockets in the upper distal corners of the manus; a spine base of an anteriorly directed spine is borne on the distal edge of each projection (the inner spine was observed by the writer but broke during preparation); the dactylus is covered with irregularly spaced shallow pits; although little remains of the pollex, it appears almost rectangular in cross-section, pitted like the dactylus, and inclined downward from the manus. ”

Discussion. Based upon the above-reported original description, this manus has strong propodus and dactylus that do not fit clearly the typical characters of a raninid manus. Indeed according to Feldmann (pers. comm., 2015) the manus clearly resembles that of a lobster or a xanthid. In conclusion, this species cannot be assigned to Ranina and this manus might well belong to a variety of other decapod groups.

Figures

Fig. 20 - Ranina burleighensis Holland in Holland & Cvancara, 1958; holotype, USNM 562094 (x 2.2).