RAPANINAE, Gray, 1853

Powell, Charles L. & Houart, Ii and Roland, 2022, Califrapana: a new genus of California and Bája California late Oligocene to early Miocene muricids previously attributed to the genus Rapana (Mollusca: Gastropoda: Muricidae), PaleoBios 38, pp. 1-19 : 3-9

RAPANINAE GRAY, 1853 ( AS RAPANANINA) CALIFRAPANA POWELL AND HOUART, N. GEN.

Califrapana vaquerosensis ( Arnold, 1907) n. comb.

Purpura vaquerosensis Arnold, 1907:426 , pl. 52, figs. 1a, b; Arnold and Anderson 1907, pl. 15, figs. 1a, b.

Rapana vaquerosensis . Wiedey 1928:115–116; Clark 1929, pl. 28, figs. 5, 6; Loel and Corey 1932:244–245, pl. 50, figs. 1–3a, b, pl. 51, figs. 2, 3; Bremner 1933, fig. 5; Squires and Fritsche 1978:15, pl. 1, figs. 2–6.

Rapana imperialis Hertlein and Jordan 1927:631–632 , pl. 20, fig. 1.

Rapana serrai Wiedey, 1928:116–117 , pl. 9, figs. 4–6.

Rapana vaquerosensis imperialis . Loel and Corey 1932:246, pl. 51, figs. 1a, b; pl. 52, figs. 1a, b; pl. 53, figs. 1a–c, 2, 3a–c, 4; pl. 54, figs. 1, 2a, b; pl. 55, figs. 1a, b. Bremner 1933, pl. 2, fig. 4. Hanna 1943:176, fig. 64-18. Avila and Weaver 1969:59,

pl. 34, figs. 1a, b. Stadum 1973:25, pl. 3, fig. 10. Squires

and Filewicz (eds.) 1983:172, unnumbered figure. Squires 1997:301, fig. 4a (refigure of Squires and Filewicz (eds.) 1983).

FIGS. 2–10

Generic Diagnosis —A large, heavy-shelled muricid variable in most of its sculptural features, but which can be distinguished from other similar looking genera by 1) its heavy shell, 2) an aperture that is bluntly pointed at both ends, and 3) the siphonal fasciole, which has a wide, shallow, ventrally open channel that points downward, easily separating it from other genera.

Type species — Purpura vaquerosensis Arnold, 1907 , by original designation.

Illustrated specimens — Nine specimens for the genus are illustrated here: five adult shells which show the range of sculptural variability and three juveniles showing ontogeny. The first is Rapana imperialis, Hertlein and Jordan (1927 , pl. 20, fig. 1; also Loel and Corey 1932, pl. 54, fig. 1, pl. 55, figs. 1a, b), holotype CAS G 70611.00 from locality CAS G 70611 (=locality LSJU 57) ( Fig. 2). Second is Rapana vaquerosensis imperialis , of Loel and Corey (1932; pl. 53, figs. 1a–c), hypotype (as plesiotype) UCMP 31627 from locality UCMP 6128 ( Fig. 3). The third illustrated specimen is R. v. imperialis , of Loel and Corey (1932, pl. 52, figs. 1a, b), plesiotype UCMP 31625 from locality UCMP A311 ( Fig. 4). Specimen four is the holotype of Purpura vaquerosensis Arnold (1907 , pl. 52, figs. 1a, b) (also Loel and Corey [1932, pl. 50, fig. 2]), holotype CAS G 61932.01 (= holotype LSJU 208) from CAS locality 61932 ( Fig. 5).The fifth is the holotype of R.serrai Wiedey (1928 , pl. 9, figs. 4–6) SDSNH holotype 13 from locality SDSNH and LSJU 442 ( Fig. 6). The sixth illustrated specimen is R. vaquerosensis , of Loel and Corey (1932, pl. 50, figs. 3a, b), hypotype (as plesiotype) UCMP 31621 from locality UCMP A543 ( Fig. 7). Hypotype seven is a juvenile specimen of R. v. imperialis illustrated by Loel and Corey (1932, pl. 53, fig. 3a–c), hypotype (as plesiotype) UCMP 31628 from locality UCMP 6128 ( Fig. 8). The specimen picked as hypotype eight is a juvenile specimen of R. v. imperialis , of Loel and Corey (1932, pl. 53, fig. 4), hypo- type (as plesiotype) UCMP 31629 from locality UCMP 6128 ( Fig. 9). Hypotype nine is also a juvenile specimen of R. v. imperialis , of Loel and Corey (1932, pl. 53, fig. 2), hypotype (as plesiotype) UCMP 31630 from locality UCMP 6128 ( Fig. 10).

Type locality —The type locality is here changed from the Vaqueros Formation on Lynch Mountain (Tierra Redondo fide Keen and Bentson 1944) in Monterey County, California to the Vaqueros Formation at Tierra Redonda Mountain in San Luis Obispo County north of Lake Nacimiento, central California.

Occurrences — Califrapana n. gen. has a limited geographic range from central California south to northern Bája California Sur, México ( Fig. 11) with a distributional gap from northern San Diego County, California south to northern Bája California Sur. Califrapana vaquerosensis is reported in the “Vaqueros” Formation from San Luis Obispo County ( Arnold 1907 [locality modified here], Wiedey 1928, as R. serrai, Loel and Corey 1932 , the “Vaqueros” Formation in Ventura County ( Loel and Corey 1932, Cushman and Leroy 1938, Squires and Fritsche 1978) (common their lower unit and rare in the middle unit, absent in the upper unit), Haworth 1980, Moore 1987), “Vaqueros” Formation in the Santa Monica Mountains, Los Angeles County ( Loel and Corey 1932, Oborne 1987), undifferentiated rocks attributed to the Sespe/”Vaqueros” formations in the Santa Ana Mountains of Orange County ( Loel and Corey 1932, Yerkes 1957, Schoellhamer et al. 1981, CASG collections), and the San Joaquin Hills ( Loel and Corey 1932). The species is also reported from the “Vaqueros” Formation on in the Southern California Bight on San Miguel ( Loel and Corey 1932, Weaver and Doerner 1969, J.T. Smith 1991, CAS collections) and Santa Rosa ( Loel and Corey 1932, Avila and Weaver 1969, J.T. Smith 1991, CAS collections) islands. Some rocks attributed to the “Vaqueros” Formation on the Channel Islands are considered middle Miocene in age ( Powell and Geiger 2019) as are some from the Isidro Formation (=Ysidro Formation of Domning 1978 and Beal 1948) in central Baja California (J.T. Smith 1986), but not strata containing C. vaquerosensis . Elsewhere it occurs in the lower part of the Isidro Formation from between Arroyo San Ignacio to Arroyo la Purisima, Baja California Sur (J.T. Smith 1984).

Age Range —late Oligocene to early Miocene (see below).

Etymology —The name is a combination of “Calif” for California and Bája California where this new genus is found, and “rapana” for the genus Rapana with which it has been long confused. Rapana from Latin [rapa or rapum]=rave, turnip, edible vegetable with a globular root, and [-ana]=like, i.e. resembling turnip roots.

Description —The morphologically variable genus Califrapana has a large and heavy shell that shows considerable variability in shape, from ovate ( Figs. 5, 7) to diamond shaped ( Figs. 3, 4, 6, 8–10). The spire is broadly rounded, short to moderately high with little sculpture except for the spiral cords at the base of the spire whorls. The specimens illustrated herein are all previous holotypes, paratypes, and (or) hypotypes.

Sculpture is variable and consists of two styles. The first is only observable on well preserved specimens and consists of faint, widely and evenly spaced shallow, spiral cords ( Figs. 6, 8–10). Some specimens show rows of larger to moderate spiral nodes of varying strength primarily at the base of the whorl on the ultimate whorls ( Figs. 5, 6). In addition, all specimens have lines of nodes near the shell’s shoulder ( Figs. 2–10), with a lesser and secondary line some distance below ( Figs. 2–4, 6–10). The nodes higher on the ultimate whorl number between six and nine and may be closed bumps ( Figs. 4–6, possibly 7) to spines that open in the direction of growth ( Figs. 2, 3, 8–10) similar to those seen in the muricid genus Forreria ( Jousseaume, 1880) .

The aperture is difficult to see in most specimens but is well exposed in Figures 2, 3, and 8. It is pointed at both its anterior and posterior ends. Nearest the columella it is broadly and shallowly rounded meeting at the pointed anterior and posterior ends. The outer lip of the aperture is much more rounded and puckered by the expressions of the major spiral sculpture. The point of inflection cor- relates with the major row of nodes on the shoulder of the ultimate whorl.

Figures 8–10 illustrate a sequence of larger to smaller juvenile specimens collected from Plano Trabuco in the Santa Ana Mountains, Orange County, southern California. These specimens show a progression of the nearly closed siphonal fasciole pointing downward ( Fig. 10) to one that is more typical for the genus/species with a large open channel ( Figs. 8, 9).