Paguristes ” johnsoni Rathbun, 1935a
publication ID |
https://doi.org/10.5252/geodiversitas2024v47a13 |
publication LSID |
urn:lsid:zoobank.org:pub:F5144147-C045-48FD-8128-7F822CDE6B18 |
DOI |
https://doi.org/10.5281/zenodo.17243640 |
persistent identifier |
https://treatment.plazi.org/id/F77987B8-FFA3-FF83-119B-C9B2AB33FB37 |
treatment provided by |
Plazi |
scientific name |
Paguristes ” johnsoni Rathbun, 1935a |
status |
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“ Paguristes ” johnsoni Rathbun, 1935a
( Fig. 11 View FIG )
Paguristes johnsoni Rathbun, 1935a: 78 , pl. 14.13-14.18. — Cope et al. 2005: 101, pl. fig. 6.2.
TYPE MATERIAL. — Holotype. United States • Alabama, Wilcox County, Prairie Creek and Pine Barren section; Porters Creek Formation ; Paleocene (upper Danian); USNM MO 371705 About USNM (right propodus).
Paratype. United States • 1 specimen; same as for the holotype; USNM MO 371706 About USNM (left minor propodus and dactylus) .
ADDITIONAL MATERIAL EXAMINED. — United States • 1 specimen; Alabama, Lowndes County, Mussel Creek roadcut ( 31°58’17”N, 86°42’15”W), ALMNH loc. 3; Clayton Formation, Pine Barren Member , lower middle NP2 nannofossil zone; Paleocene (lower Danian); ALMNH: Paleo:21483 (right propodus + base of dactylus) GoogleMaps • 1 specimen; idem; ALMNH: Paleo:21484 (left dactylus) GoogleMaps • 1 specimen; idem; ALMNH: Paleo:21485 (right dactylus) GoogleMaps • 1 specimen; idem; ALMNH: Paleo:21486 (?left fixed finger) GoogleMaps • 1 specimen; idem; ALMNH: Paleo:21487 (right dactylus) GoogleMaps • 1 specimen; idem; ALMN-H: Paleo:21555 (left merus) GoogleMaps • 1 specimen; idem; UF 303860 (right dactylus) GoogleMaps • 1specimen; Alabama, Sumter County, Tombigbee River, Black Bluff ( 32°22’22”N, 88°2’38”W), ALMNH loc. 5; Porters Creek Formation ; Paleocene (upper Danian); ALMNH: Paleo:21495 (right propodus) GoogleMaps • 1 specimen; idem; ALMNH: Paleo:21496 (right dactylus) GoogleMaps • 1 specimen; idem; GSA-I21012 (right dactylus) GoogleMaps • 1specimen; Alabama, Wilcox County; Porters Creek Formation ; Paleocene (upper Danian); GSA-I20984 (right propodus) .
TYPE HORIZON. — Porters Creek Formation (Sucarnoochee beds in Rathbun 1935a), upper Danian.
TYPE LOCALITY. — Prairie Creek and Pine Barren section, Wilcox County, Alabama, United States.
DIAGNOSIS. — Major palm short; about as long as high; tubercles with pit in center; diamond-shaped in cross-section; with sharp, convex upper and lower margins; upper margin shorter than lower margin; rounded ridges on outer and inner sides. Major dactylus with tubercles with pit in center and non-tubercular patches with setal pores on outer, upper, and part of inner sides; occlusal surface with a few large teeth and a smaller tooth on outer side of first tooth proximally, and a row of connected small teeth toward distal end.
MEASUREMENTS. — Palm length (mm): ALMNH:Paleo:21483: 5.4 (as preserved); USNM MO 371705: 15.6; ALMNH:Paleo:21495: 10.4; GSA-I20984: 10.6 (as preserved).
DESCRIPTION
Reference is made to Rathbun (1935a: 78). Additionally: major dactylus curved inward; tubercles with pit in center and non-tubercular patches with setal pores on outer, upper, and part of inner sides; occlusal surface with a few large teeth and a smaller tooth on outer side of first tooth proximally, and a row of connected small teeth toward distal end.
REMARKS
The single right propodus available ( ALMNH:Paleo:21483) from Mussel Creek is incomplete but closely resembles the holotype of Paguristes johnsoni ( USNM MO 371705 About USNM , right propodus) and other right propodi ( ALMNH:Paleo:21495, right propodus; GSA-I20984 , right propodus) from the upper Danian Porters Creek Formation in Alabama in terms of overall shape, size, and distribution of the ornamentation, and the ridge on the outer surface.
The base of the dactylus is preserved along with the propodus from Mussel Creek (ALMNH:Paleo:21483), showing the base of the first large tooth and an adjacent small accessory tooth on the outer side that large tooth. This pattern resembles other isolated dactyli from Mussel Creek and dactyli from the Porters Creek Formation (ALMNH:Paleo:21496, GSA-I21012), which allows us to assign these specimens to P. johnsoni as well. The sample also contains an isolated finger that could be a fixed finger of this taxon ( Fig. 11I, J View FIG ). It contains a row of small teeth on the occlusal surface and might belong to the minor claw of this taxon because large teeth on the occlusal surface are often seen on both fingers of the major claw in paguroids, whereas small teeth are often seen on the minor claw in paguroids (e.g., Forest et al. 2000). The oblique row of small teeth on its inner proximal part matches that of the base of the fixed finger of the propodus (ALMN-H:Paleo:21483). Dactyli of the major claw were unknown from this species thus far. A left merus possibly belonging to the same species was also found (ALMNH:Paleo:21555).
This species was briefly discussed in Bishop (1983: 419), citing a personal communication with Jaques Forest, who was in doubt that Paguristes whitteni Bishop, 1983 , and P. johnsoni could be assigned to Paguristes or even paguroids. Tubercular propodi do not necessarily imply a paguroid affinity. Indeed, the propodi of Paguristes whitteni belong to carapace specimens of the brachyuran crab Dakoticancer australis Rathbun, 1935a (see Kornecki et al. 2017), also common at the same locality in Mississippi. We cannot assign the tubercular elements herein to a brachyuran carapace from the same assemblage. The dactyli and propodi are too large for Alahexapus martini ( Feldmann, Schweitzer & Portell, 2014) n. comb. and the (distal) cheliped elements of other brachyuran taxa (see below) do not resemble the propodi/dactyli of P. johnsoni . The cheliped elements also cannot be linked to a brachyuran carapace from the Porters Creek Formation. Given the extensive collecting efforts at the Mussel Creek roadcut since 2010, the likelihood of finding other brachyuran taxa to which the claw elements could belong is low. We therefore suggest that the specimens represent a paguroid.
The fact that the right propodus is larger than the left propodus (see Rathbun 1935a: pl. 14.13-14.17), if both isolated elements are indeed from the same species, is inconsistent with Diogenidae , members of which usually have a larger left propodus or (sub)equal propodi (e.g., Tudge et al. 2012: 305), including Paguristes , which is mentioned to have isochelous propodi ( Fraaije et al. 2015: 590). An exception within diogenids is Petrochirus Stimpson, 1858 , but this taxon has scabrous ornamentation in the type species Petrochirus diogenes ( Linnaeus, 1758) (see Hyžný & Dulai 2021: fig. 43.7) not seen in P. johnsoni and various fossil Petrochirus ( Beschin et al. 2002, 2006, 2012). The dactyli herein closely resemble a dactylus identified as Petrochirus sp. from the Early Miocene of Venezuela ( Feldmann & Schweitzer 2004: pl. 1.2-1.4), but this record has more teeth on the occlusal surface. It is likely these species belong to the same genus. We have not found close matches with other Petrochirus spp. More complete material with both left and right cheliped would be necessary to further evaluate the genus and family placement. For now, we treat the specimens as “ Paguristes ” johnsoni within Paguroidea .
The assignment of our material to P. johnsoni implies a range extension into the early Danian in Alabama. Cope et al. (2005) ascribed a propodus from the Clayton Formation of southern Illinois to P. johnsoni . The level of this specimen within the Clayton Formation was not reported, but potassium-argon dating on glauconite on the oldest sample from the Clayton Formation returned a date of 60.6 ± 1.3 Ma ( Reed et al. 1977). This date suggests it is not the earliest Danian and that this propodus from Illinois is probably younger than the specimens herein.
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.
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Paguroidea |
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Paguristes ” johnsoni Rathbun, 1935a
Klompmaker, Adiël A., Martin, P. George, Hyžný, Matúš, Bowman, Andrew R., Phillips, George E. & Portell, Roger W. 2025 |
Paguristes johnsoni Rathbun, 1935a: 78
COPE K. H. & UTGAARD J. E. & MASTERS J. M. & FELDMANN R. M. 2005: 101 |
RATHBUN M. J. 1935: 78 |