Gaillard Cut (Miocene of Panama)

Where: Panama City, Panama (9.0° N, 79.7° W: paleocoordinates 8.4° N, 77.6° W)

• coordinate estimated from map

When: Hemigfordian mammal zone, Cucaracha Formation, Early/Lower Hemingfordian (20.4 - 16.0 Ma)

• The Cucaracha Formation at the Gaillard Cut is underlain by the marine Oligo-Miocene Culebra Formation and overlain by the Panama Formation, the latter of which includes marine (La Boca) and volcanic (Pedro Miguel Agglomerate) sediments reported to be early Miocene in age (Woodring, 1957)

• formation-level stratigraphic resolution

Environment/lithology: deltaic; lithified, tuffaceous, green, yellow, sandy, conglomeratic claystone

• The fossil mammals were collected from the Cucaracha Formation, which principally consists of “massive generally grayish yellow green waxy highly slickensided bentonic clay” (Woodring, 1957:39) that forms distinctive outcrops along the Canal. This formation also contains sands and pebble conglomerates, lignitic beds (also see Graham, 1988), and a dacitic welded tuff.

Size class: macrofossils

Preservation: original phosphate

Collected by R. H. Stewart, J. A. Stewart and F. C. Whitmore in 1956-1968

Primary reference: B. J. MacFadden. 2006. North American Miocene Land Mammals from Panama. Journal of Vertebrate Paleontology 26(3):720-734 [B. Beatty/B. Beatty/J. Ceballos]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 144879: authorized by Carlos Jaramillo, entered by Juliana Ceballos on 19.05.2013, edited by Juan Carrillo

Creative Commons license: CC BY (attribution)

Taxonomic list

• The majority of these fossils were collected from “Cucaracha Reach, Station 1998–00, 600 feet west of the center line of Panama Canal. Two other entries were made to document smaller parts of this collection: (1) 1956; “Contractor’s Hill, Gaillard Cut, Canal Zone, Cucaracha formation (lower Miocene), about 35 feet above top of ash flow.” Data with USNM 171001 (rhino R femur); and (2) 1965; “Cucaracha exposure in Cucaracha Reach, south of Contractor’s Hill, ex- tends from Station 1997 to Station 2006, a distance of 900 feet.” (Whitmore, F. C., Jr., unpublished field notes, book 3 [1960 to 1969], page 17. Archived in Department of Paleobiology, USNM).
unclassified
  -
Taxon indet.
Family Amphicyonidae Haeckel (1866) or Hemicyonidae: USNM 171010, L radius with proximal articular surface and proximal portion of the shaft (body); USNM 49440 (part), proximal L ulnar fragment
Mammalia
 Chiroptera - Phyllostomidae
Phyllostominae indet. Gray 1825 leaf-nosed bat
New genus and sp. of large insectivorous phyllostomine
 Carnivora - Amphicyonidae
cf. Daphoenodon sp. Peterson 1909 bear-dog
 Carnivora - Procyonidae
Bassaricyonoides sp. Baskin and Morea 2003 procyonid carnivore
 Carnivora - Canidae
Tomarctus brevirostris Cope 1873 bone-crushing dog
USNM 494437, partial L mandible with m1; 49440 (part), R c, and m3.
 Perissodactyla - Equidae
Archaeohippus sp. Gidley 1906 anchitheriine horse
USNM 23157, R M1 or M2; 23184, R calcaneum.
Anchitherium clarencei Simpson 1932 anchitheriine horse
USNM 23156, L upper cheek tooth; USNM 494438, mandibular fragment with R p2–p4.
 Perissodactyla - Rhinocerotidae
Floridaceras whitei Wood 1964 rhinoceros
USNM 183060, R and L mandibles with i2 tusks, R p2–m3, L p2–p4, m1, m2; 23178, R partial mandible with m3 erupting; 23186, Lp3; 23189 (part), Lp2; 23190, Lp4; 171001, R femur fragment with head and distal articular surfaces (also see list of unallocated fragments listed above under Meno- ceras barbouri)
Menoceras barbouri Wood 1964 rhinoceros
USNM 23187, R I1; 23189 (part), R M3 and Lp2; 484439, RP2; 171005, R partial humerus with shaft and distal end. (Taxonomically unallocated material referable to Rhinocerotidae in the Gaillard Cut L. F. includes USNM 23188, upper molar fragment; 23179, upper tooth; 171026, partial upper cheek tooth; 23190, L m1; 23186, L p3; 171009, 23167, 23176, 23185, tooth enamel fragments; 171004, thoracic vertebra; and miscellaneous uncatalogued specimens)
 Artiodactyla - Camelidae
cf. Floridatragulus nanus Patton 1969 camel
 Artiodactyla - Merycoidodontidae
Merycochoerus matthewi Loomis 1924 oreodont
USNM 23158, R mandible with partial p4, partial m1, m2–m3; USNM 23159, partial skull with R C and P1, R and L M1–M3, and incomplete zygomatic arches, R man- dible with partial m1, m2–m3, L mandible with m2–m3; 23162, R m2; 171016, L p1 (fragments from other taxa are included in this catalog entry); 23163, upper molar crescent and unworn m3 tal- onid; other uncatalogued fragments in USNM collection.
 Artiodactyla - Protoceratidae
Paratoceras wardi Patton and Taylor 1973 protoceratid
Upper dentition: USNM 23153, maxilla with R P3–M3; 23165, partial maxilla with L M1–M3; 23171, R and L M1; 23179, R M1; 171040, cranial fragment with L frag- ment P4, M1–M3. Lower dentition: 23147, L partial mandibular ramus with m1–m3; 23148, L mandible with fragment with p4, m1–m3; 23149, R mandible with dp2–dp4, m1; 23152, L m3; 23154, R partial mandible with p2–m3; 23155, R m1–m3; 23161, L p4–m3; 23170, partial mandible with L p3, m1–m3 and R m1; 23172, L ?dpx, m2–m3; 171006, fragmentary L mandible with p3–p4; 171011, R p3; 171029, L m1–m2; 171025, Rm2; SMU 68102, L p4–m3. Miscellaneous isolated or associated upper and/ or lower cheek teeth: USNM 23151; 23168, 23173–23176, 171027, 171030, 171032–171036, plus uncatalogued specimens; 171037– 171038, tooth fragments. Postcranials: 171028, limb bone frag- ments, L astragalus
 Artiodactyla - Moschidae
cf. Parablastomeryx sp. Frick 1937 musk deer
cf. Machaeromeryx sp. Matthew 1926 musk deer
 Rodentia - Sciuridae
Petauristodon sp. Engesser 1979 squirrel
new sp.
Nototamias sp. Pratt and Morgan 1989 squirrel
new sp.
 Rodentia - Heteromyidae
Proheteromys sp. Wood 1932 rodent
 Rodentia -
Texomys stewarti Slaughter 1981 rodent