Contributions to Zoology, 67 (4) 237-255 (1998)
SPB Academic Publishing bv, Amsterdam
The Dakoticancridae (Decapoda, Brachyura) from the Late Cretaceous of
North America and Mexico
G.A. Bishop¹,R.M. Feldmann² & F. Vega³
1 Department of Geology and Geography, Georgia Southern University, Statesboro, Georgia 30460, U.S.A.;
2 3 Department of Geology, Kent State University, Kent, Ohio 44242, U.S.A.; Institute de Geologla, UNAM,
Ciudad Universitaria, Coyoacan, Mexico, D.F. 04510, Mexico
Keywords; Dakoticancridae, Brachyura, paleobiology, paleobiogeography, Late Cretaceous,
North America, Mexico, taxonomy, cladistics
Contents Abstract
Introduction 237 The podotrematous crab family Dakoticancridae includes four
of the 239 Tetracarcinus Diagnosis family Dakoticancridae genera: Dakoticancer Rathbun, Weller, Avitel-
Biology 239 messus Rathbun, and Seorsus Bishop, all known solely from
General 239 the Late Cretaceous ofNorth America. Lathelicocarcinus Bish-
239 referred the be Fine Reproductive structures op, originally to family, must reassigned.
details of of Intersexuality of Dakoticancer overanus Rathbun, anatomy, preserved on specimens D. overanus
1917 239 Rathbun and A. grapsoideus Rathbun, permit description of
Sensory apparatus 240 genital openings and interpretation of functional morphology
240 Feeding and food gathering of appendages. Although one species, D. australis Rathbun,
Burrowing 241 has been found associated with burrow structures, all were
Decoration 241 probably vagrantepifaunal animals on fine- to medium-grained
241 substrata. Color patterns siliciclastic Food was probably obtained by gener-
alized low-levelpredation and scavenging. Results ofa cladistic Genera and species 241 analysis are consistent with the stratigraphic data suggesting to and species 246 Systematic keys genera that T. subquadrataWeller is nearest the rootstock ofthe family Carapace key 246 and that other taxa within the family are derived from it. Chelipede key 246
Cladistic analysis 246
Introduction Paleoautecology 247
General 247
Paleoautecology of Dakoticancer overanus 247 The Dakoticancridae comprise a small, homo- Paleoautecology of Dakoticancer australis 248 of geneousgroup podotrematous crabs that thrived Paleoautecology of Avilelmessus grapsoideus 249 in North America during the Late Cretaceous. Paleoautecology of Tetracarcinus subquadratus 250 They that Dakoticancroid crab assemblages 250 are sufficiently distinctive they remain the sole
251 in Origin of the Dakoticancridae family the Dakoticancroidea. The name of the
Dakoticancridae is derived from the family’s type Cretaceous paleogeography 252 genus, Dakoticancer, which in turn is a name de- General 252
rived from the occurrence of the in Western Interior Seaway 252 type species
Mississippi Embayment 252 South Dakota, (Dakota + Cancer = Dakoticancer
Northern Plain 253 Atlantic Coastal - Dakoticancridae).
Western Gulf Coastal Plain and Mexico 253 Weller described the first dakoticancroid crab of dakoticancrids 254 Biogeographic range in 1905 when he described Tetracarcinus subqua-
dratus from New in Interpretation 254 Jersey figured 1905a, figs. 4, and and References 254 5, 6, again in 1905b (same figures but
Downloaded from Brill.com10/11/2021 12:22:01PM via free access 238 G.A. Bishop et al. - Late Cretaceous Dakoticancridae (Decapoda)
with 5 and 6 reversed) and four specimens figured discerned and described. The assignment to the
in 1907 (PI. Ill, figs. 16, 17, 18, and 19). Weller Atelecyclidae was maintainedby their allusion to
did not assign the crabs to a family at the time of Rathbun’s assignment and by a comparison to the
definition (Weller, 1905a: 328) but subsequently atelecyclid Bellia picta Edwards from the coast
referred it to the family Dromiacea (sic)(Wel!er, of Peru. It must be noted that subsequently Bellia
1907: He These 852). designated no holotype. has been assigned to the Bellidae and is no longer
specimens were probably available to Henry B. referred to the Atelecyclidae. Avitelmessus was
Roberts (1962), who, as first revisor, designated subsequently assigned to the Dakoticancridae
17 The the specimen illustrated by Weller, 1907, fig. (Glaessner, 1960). genus remains a signifi-
(NJSM #7788) and refigured by Rathbun, 1935 cant one in that it may be ancestral to another family.
(pi. 10, fig. 16) as the best preserved of the “three Glaessner (1969: 440) said: “A derivative of the
syntypes”. This specimen can be considered the Cancridea from a form like the Upper Cretaceous
lectotype. Avitelmessus (Dakoticancridae, originally placed
The family was named by Rathbun in 1917. She in Atelecyclidae) seems possible”. described Dakoticancer overana Rathbun, 1917, To this list of taxa, Bishop added two additional based to the National Mu- Lathelicocarcinus and upon specimens sent genera; Bishop, 1988b,
W.H. seum by Over, of the University of South Seorsus Bishop, 1988a. Both were based upon spec-
Dakota, from collections made in Pennington imens collected from lower Maastrichtian deposits
County, South Dakota from rocks of the Upper in Mississippi. The former genus is probably
Cretaceous Pierre Shale. In 1935, Rathbun (1935: referable to a different family and the latter is
known 40) cited the type locality as being “West side, only from the type material. Subsequent
Missouri River, a short distance below Mobridge, work on the family has resulted in the elevation eastern Corson County....”. In that same work, she of Dakoticancer overana australis to species rank described a new subspecies, Dakoticancer overana (Bishop, 1983b), as well as enhancement of our australis Rathbun, 1935, from the Ripley Formation, understanding of the biology and biogeography of
Union County, Mississippi. Rathbun (1937: 26) the included species. subsequently described Dakoticancer olsoni, but As presently understood, the group is small and
that this did limited and Bishop (1988a: 75) pointed out taxon of geologic geographic scope, although not belong in Dakoticancer. specimens are abundant in fossil Lagerstatten in
Rathbun described Avitelmessus North America. Glaessner In 1923, grap- Nonetheless, (1980) soideus from a large male specimen (USNM suggested that the family might figure prominently
#31895) collected from the Peedee Formation by in the evolutionary history of the decapod crusta-
L.W. Stephenson (Coll. #3452) “Near Hudlers Lap- ceans and applied the taxonomy of Guinot (1977,
30 1/2 miles above Wil- that three of ding, Cape Fear River, 1978) distinguished major groups crabs, mington....”, Rathbun assigned this crab to the the Podotremata, Heterotremata, and Thoracto-
Family Atelecyclidae (1923:403). She subsequently tremata, into which were integrated the traditional
(1926: 190-191, pis. 69-70) described and illustrated families of brachyurans. Glaessner’s interpretation several additional specimens from western Ten- of the evolution of the Brachyura documentedthree nessee. Kesling & Reimann (1957) further en- major times of adaptive radiations: Middle and hanced our knowledge of Avitelmessus grapsoi- Upper Jurassic, Mid-Cretaceous, and the Late deus by their description and illustration of a magni- Cretaceous-Early Paleogene. Implied, but not cited
Coon ficently prepared specimen from the Creek in the text description is a fourth radiation in the
Formation, Coon Creek, Tennessee (Univ. Mich. Eocene. No mention is made of the Dakotican-
MuseumPaleont. #33406) that preserves the dorsal, cridae on Glaessner’s chart, nor in its description;
and lateral of the and Glaessner did cite it earlier anterior, aspects carapace however, (1980: 188)
both in his “A of the with that proximal pereiopods, including chelipedes. text; similarity carapace
This specimen was described in great detail and of Avitelmessus Rathbun does not apply to its [Poro- illustrated by nine figures. A color pattern was raria eocenica Glaessner, 1980] median portion
Downloaded from Brill.com10/11/2021 12:22:01PM via free access Contributions to 67 - Zoology, (4) 1998 239
which shows a corystoid Avitelmessus is pattern. cridae must be made by interpretation of functional
very close to Dakoticancer. [Pororaria eocenica morphology, occurrence, and associations with has since been referred to the Portunidae (Feldmann other organisms. Where not stated, observations & As Guinot Maxwell, 1990)]. (1978) remarked, have been made on Dakoticancer overanus and these should genera not be assigned to the Dromia- are extended to the family. The number of speci- cea”. This is an interesting situation, especially that mens of species and the completeness of that since Glaessner called attention to the Dakotican- material far exceeds those of the other species. cridae as an unanswered problem (1960: 47): “...(3)
the Upper Cretaceous Dakoticancridae including
Avitelmessus Rathbunand their relation grapsoideus Reproductive structures
to of a group large-eyed American crabs com-
antennatus prising Archaeopus Rathbun, “Plagiolo- The of Dakoticancer genital structures overanus vancouverensis Carcineretes phus" (Woodward), lie on the coxae of the pereiopods (Figs 1.4, 1.5); and Within this Ophthalmoplax. incompletely the oviduct perforations on the coxa of the third known lie the the group may key to genetic re- and pereiopod the seminal ducts on the coxa of lationships of the and other Dorippidae Oxyrhyncha, the fifth pereiopods (Bishop, 1984b). The oviduct the Ocypodidae, and possibly the Portunidae”. If, perforations are small oval openings near the Glaessner as suggests, they are not assignable to corner of the posterior-proximal coxa, just in front the Dromiacea, where do the dakoticancroids of the articulator with the sternum. The orifice is belong? and, what was their origin? Guinot (1993) nearly surrounded by a raised rim separating considered the Dakoticancridae to be the sole family abundant setal pits on the outside from smooth within the Dakoticancroidea; this superfamily she exoskeleton on the inside. A specimen approxi- considered to be separate and apart from both the mately 15.63 mm wide has oviduct perforations Dromiacea and Archaeobrachyura. 0.15 mm in diameter. The seminal duct is small
and usually not visible, normally being pressed
against the second somite of the abdomen. Diagnosis of the family Dakoticancridae Only
when the coxa is flexed the seminal duct is visible.
Bishop and have Carapace rectangular to transversely ovoid, almost Sturgeon (in preparation)
that the of as wide as demonstrated Avitelmessus long; rostrum narrow, bilobed; orbits gonopores
well grapsoideus are carried on the of developed, rimmed; eyes sheltered by orbits coxae pereiopod
3 when median or 5 retracted; part of cardiac groove weak, (oviducts) pereiopod (seminal duct). The oviduct gastric regions hardly separated from cardiac in- perforations are small openings situated testinal near the region, branchiocardiac groove well de- posterior articulation of the coxal
located articulation with the veloped, pleural sutures on carapace sides; sternum and the seminal duct genital on openings coxae, female on third leg and openings are found on the proximal side of the male on the fifth; fifth Sternum coxal legs much reduced. articulation, often hidden if pereiopod 3 is of female without in longitudinal grooves. Chelae a relaxed position. equal. (Rathbun, 1917: 385; Glaessner, 1969; Bis- hop, 1983c: 424.)
Intersexuality of Dakoticancer overanus Rathbun,
1917
Biology
and Primary secondary sexual characteristics of General Dakoticancer overanus and two known intersexes
have been described by Bishop (1974, 1983a). Because of the absence of all in- These include living forms, the characteristics summarized in ferences regarding the biology of the Dakotican- Table I.
Downloaded from Brill.com10/11/2021 12:22:01PM via free access 240 G.A. Bishop et al. - Late Cretaceous Dakoticancridae (Decapoda)
Table I. Sexual characters observed on specimens ofDakoticancer overanus.
Primary sexual characteristics Secondary sexual characteristics
Females Oviduct perforation in coxa of P Abdomen wide and ovate 3 Sternum gently dished
Sternal somites granulate on distal edges
and a few along midline ofeach somite
Males Seminal duct on coxa of P Abdomen narrow and rectangular 5 Sternum medially troughed
Sternal somites granulate mesially from
distal abdominal edge to groove
Intersex 1 Oviduct? perforation on left P Abdomen intermediate and rectangular 3
Granulate as in males
Intersex 2 Oviduct on coxae P Abdomen intermediate, rectangular 4
Seminal duct on coxae P Granulate as in males 5
Sensory apparatus laterally by extraorbital and ventrally by suborbital
spines. The eyestalks are long, bulbous proximally,
The orbits of specimens referred to Dakoticancer and fold completely into the orbits. overanus are inclined forward and outward and in front view are divided into two fossae, emarginated into anterior margin. The orbits are bounded by Feeding and food gathering the rostrum mesially, by the extraorbital spine distally, and by a suborbital spine ventrally. They The chelipedes and claws of Dakoticancer over- are rimmed, and the inner orbital fossa is defined anus are equal, the palms are twice as long as high, by a separate, tuberculate inner orbital ridge fingers downturned. The third maxillipedes are extending from edge ofrostrum to the innerorbital broad and spatulate; the exognath is half as wide
inside septum. It is set somewhat the outer orbital as the endognath, with ischia reaching beyond the rim. The innerorbital fossa is larger than the outer line of the rostrum. The inner exopod margins are fossa and bears spines on its lower and outer bor- granulate. The endopods do not meet closely, are der, and has a suborbital drain or trough between. longitudinally grooved, and are finely granulate
The eyestalks reach into the second fossa and taper especially along the inner margin. The buccal frame
retractable for is raised into the sides medially; they are completely margin a very narrow rim; protection. Bishop (1984b) described a reticulated are parallel. The third maxillipede coxa/basis inner orbital sensory structure, the orbital bulla buttresses against the anteriormost, trapezohedral reticularis, situated on the outer surface of the inner sternal somite and the carapace edge, where the orbital fossa. buccal frame meets the pterygostomial margin.
One In joint of the antenna has been seen just below Tetracarcinus subquadratus. the chelae are the origin of the eye and is granulated. The second equal, bulbous, and small, commensuratewith cara- antenna is smaller and lies between first antenna pace size. The palm is longer than high and smooth,
for the surface. and suborbital spine. except granulate upper
In Avitelmessus grapsoideus the orbital width The chelipedes of Avitelmessus grapsoideus are is 44% of the total carapace width. The orbits are symmetrical, the claws are as long as high, with deeply incised into the anterior margin with the equal fingers carrying three molariform proximal
rimmed teeth and The two fossae, by granulate emarginations; a cutting edge distally. merus, carpus, the inner orbital fossa is ahead of the and set outer propodus, dactylus are very granulate to spiny, fossa and is separated from it by a trough, bounded especially on the outer surfaces.
Downloaded from Brill.com10/11/2021 12:22:01PM via free access Contributions 67 - 1998 to Zoology, (4) 241
Burrowing and of the meri leading trailing edges are very spiny
and their lower and surfaces upper (the surfaces
Evidence for dakoticancrid crabs is that burrowing by have to slide past as the crab walks) are smooth.
equivocal. Bishop (1981) observed that, The and although carpus propodus of these ambulatory legs Dakoticancer is overanus associated with must have been about the frequently same length as the merus.
a few the concentrically layered straight burrows, The fifth legs are much smaller than the others
burrows are neither abundant to be their and enough appear to have been held posteriorly or even domiciles nor are He above the the they large enough. concluded, carapace, suggesting possibility for that the therefore, species was not an obligatory carrying behavior in these crabs. The last pair of burrower. legs in Dakoticancer overanus are also slender and
However, molds oHD. australis havebeen much found reduced in length. They were probably carried inside burrows in the Portrerillos Formation in in a subdorsal position as well.
Nuevo León, Mexico. The diameters of the burrows
range from 7 to 12 cm. These crabs, inferred by Color patterns & Feldmann be Vega (1991) to exuviae, are pre-
served within burrows and have preserved ap- & Reimann Kesling (1957: 8) described patterns pendages that remain articulated, but show dis- on the exoskeleton of Avitelmessus grapsoideus location of the ventral of To side the carapace. as remnants of color markings or patterning, with date, more than 20 specimens of D. australis have the comment that “We strongly suspect that the been collected at this locality, all within galleries colors have changed somewhat, but that the and all with pattern dislocated plastrons. This suggests a has been faithfully retained”. The pattern described of behavior molting within burrows, which is un- consisted of “...a medium background, dark spots common for most brachyurans as molting inside and blotches, and lines” with light ...... “preserved burrows has not beenobserved frequently in extant of parts the exoskeleton on the carapace...lighter crabs (Vega & Feldmann, 1991). Dakoticancer on the mesogastric area and the ridges of the australis specimens from the Cardenas Formation area...”. protogastric The carapace has dark umber in San Luis Potosl, east-central Mexico, are not spots, differing in size and shape, being larger and found associated with burrows, and most of them in more elongate concave parts on the protogastric, possessed articulated appendages. It is possible that epibranchial, and hepatic The these latter regions. carapace specimens are corpses, rather than molts, pattern has a microscopic pattern of labyrinthic or that the observed differences in preservation light lines, seen only with magnification. The meri between assemblages of Nuevo Leon and San Luis of the chelipedes are lighter below than above, Potosi reflect different taphonomic histories, rather the carpi are lighter on the side near the body and thandifferent molting behavior (Vega et al., 1995). have dark blotches on their and distal upper surfaces
and rosettes of small their spots on proximal surfaces. The chelae are lighter on the side near Decoration the The body. walking legs are lighter below with
transverse dark blotches on their sides. These The of. pereiopods Avitelmessus grapsoideus con- consistent patterns are with counter shading seen sist of the large chelipedes, three pairs of large, in that many decapods live in shallow water. long, flattened, similarly-sized walking legs P2,
P3, and P4, and a much reduced, ?subdorsal fifth
of pair pereiopods P5. Pereiopods 2, 3, and 4 Genera and species apparently are similar in size and shape. Each has a long merus which extends to be on line with the As it is presently understood, the family Dakoti- midpoint of the on the Each of cancridae embraces four carpus chelipede. genera and five species these is flattened and oriented pereiopods with the known only from the continental interior and blade backward and downward. Atlantic slanting The and Gulf coastal plains ofNorth America.
Downloaded from Brill.com10/11/2021 12:22:01PM via free access 242 G.A. Bishop et al. - Late Cretaceous Dakoticancridae (Decapoda)
Dakoticancer Rathbun, 1917 pits present at junction of cervical and antennal
grooves. Tumid regions granulate, hind margin
- width of into Diagnosis. Carapace rectangular to transversely nearly carapace,not developed a shelf,
and width about front raised and Chelae twice as ovoid, length equal, narrow, granulate. equal, long rostrum bilobed; orbits well developed; medianpart as high. of cardiac groove weak, gastric regions hardly sep-
arated from cardiac-intestinal branchiocar- - The and region, Types. holotype (USNM 32055) para-
diac well sutures in groove developed, pleural on cara- types (USNM 32055a; 32056b-l) are deposited
on female on the collection of the United States National Mu- pace sides; genital openings coxae,
third leg and male on the fifth; fifth legs much seum of Natural History, Washington, D.C. 20560.
reduced. Chelae equal (after Bishop, 1983b: 424).
Range. - Dakoticancer overanus is known from
Type. - The type species of Dakoticancer Rathbun, the Campanian and Maastrichtian Pierre Shale or
1917 is D. overanus by original designation. equivalents in South Dakota, North Dakota, and
Montana. The earliest known specimens are from
Range. - Dakoticancer is known from 80 speci- the Zone of Exiteloceras jenneyi after which D.
I from in mens in northeastern Mexico, specimen overanus assemblages become quite common
Bexar County, Texas on the western Gulf Coastal the mid-late Campanian and early Maastrichtian.
Plain, and is very abundant in the Mississippi Em-
bayment and Western Interior Seaway in rocks of Dakoticancer australis Rathbun, 1935
and Maastrichtian and from Mexico 1.6 - Campanian age (Figs. 1.9)
(Vega & Feldmann, 1991; Vega et al., 1995).
Diagnosis. - “Carapace large, slightly longer than
- branchial and Included species. Two species have been wide, widest across hepatic regions
described. Dakoticancer overanus Rathbun, 1917 (sides nearly parallel), well differentiatedby groov-
is abundant in the Western Interior Seaway (ca. es, ornamented by granules over entire surface.
5,000 specimens) andDakoticancer australis Rath- Posterior produced into a fairly discrete shelf, not
1926 is abundant in at maximum width of hind bun, (ca. 1,000 specimens) quite carapace, margin
the Mississippi Embayment and present in Texas slightly raised. Chelae equal, short, stout, and crest- and Mexico. ed, carpal articulation very oblique; fingers short,
downturned” (Bishop, 1983b: 426).
Dakoticancer overanus Rathbun, 1917
- (Figs. 1.1 - 1.5) Types. The holotype (USNM 73840) and five
paratypes (USNM 73840) are deposited in the
Diagnosis. - Carapace of moderate size, rec- collection of the United States National Museum
tangular, slightly wider than long, widest across of Natural History, Washington, D.C. 20560.
epibranchial regions, sides sinuous, slightly con-
vergent posteriorly; high, moderately arched; Range. - Dakoticancer australis is abundant in the
cervical in the Maastrichtian grooves deep, groove prominent, relatively Mississippi Embayment early
continuous except across continuous sagittal ridge; Coon Creek Formation in the Union and Pontotoc
Dakoticancer 1 - Dakoticancer from the U.S.A.: Dorsal Fig.I. spp.: 5, overanus Pierre Shale, Mobridge, SouthDakota, 1, view of
and of view of Ventral nearly complete topotype carapace. 2, Ventral view of sternum abdomen male. 3, Outer right propodus. 4,
of of fifth Ventral view of female view male showing gonopore openings on coxae pereiopod. 5, showing gonopore openings on coxae of third pereiopod. 6-9, Dakoticancer australis from the Coon Creek Formation, Blue Springs, Union County, Mississippi,
U.S.A.: Dorsal view of male Dorsal view of 6, nearly complete holotype carapace. 7, complete paratype carapace showing promi-
Ventral view of male Outer view of nent posterior shelf. 8, nearly complete holotype carapace. 9, nearly complete right carpus, propodus, and dactylus. Scale bars equal 1 cm.
Downloaded from Brill.com10/11/2021 12:22:01PM via free access Contributions to Zoology, 61 (4) - 1998 243
Downloaded from Brill.com10/11/2021 12:22:01PM via free access 244 G.A. Bishop et al. - Late Cretaceous Dakoticancridae (Decapoda)
counties, Mississippi, from the early Maastrichtian Magothy Formation at Cliffwood, Woodbury ofMcNairy County, Tennessee, from the late Cam- Formation at Lorillard, and Merchantville Forma- panian or early Maastrichtian Navarro Formation tionofthe Delmarva Peninsula; fromthe Mississippi
near Castroville, Bexar County, Texas, the Maas- Embayment from the Coon Creek Formation of trichtian Difunta Group, in Coahuila State, Mexico, Union County, Mississippi; and from the Western and the Maastrichtian Portrerillos Formation in San Interior Seaway from one specimen from the Lewis
Luis Potosi Mexico. Shale of It from late Santonian State, Wyoming. ranges
through early Maastrichtian.
Tetracarcinus Weller, 1905
- the (Figs. 2.1, 2.2) Included species. Only type species is known.
Diagnosis. - Carapace relatively small, subquadrate,
length nearly equals width, widest across epi- Avitelmessus Rathbun, 1923 branchial regions. Rostrum small, narrow, medially (Figs. 2.4, 2.5) grooved. Lateral margins sinuous; posterolateral
and tend to be continuous - circular with margin posterior margin a Diagnosis. Carapace very large, smooth curve on steinkerns or incomplete speci- concave front, widest at midpoint; arched longi- mens, complete specimens exhibit slightly expanded tudinally, fairly level transversely. Rostrum small,
with rim. Orbits with fossae posterior margin bordering Carapace narrow, medially grooved. two
differentiated cervical two concavities in view. poorly by grooves; very forming plan Carapace
shallow medially, obsolete distally, groove delin- margin nearly forms circle from lateral orbital eating sagittal ridge broad, smooth, shallow but spines, spinose, carapace grooves poorly developed well defined. Epibranchial and metabranchial except for gastro-cardiac, proximal cervical (except separated by broad depression containing narrow obsolete gastric portion), and epimesobranchial. mesobranchial ridge. Cephalic arch relatively short, Sagittal ridge well delineated; cephalic arch poorly weakly differentiated, regions slightly tumid, differentiated except for mesogastric; scapular arch granulate; scapular arch well differentiated, tumid with well-delineatedcardiac and branchial regions, and ridged, high areas granulate; cardiac region branchial regions differentiated into epibranchial
and large relatively posteriad with a small posterior and meso-metabranchial by epibranchial groove, tubercle. Chelae equal, small; palm longer than posterior ofbranchial separated into mesobranchial high, smooth except for granulate upper surface. and metabranchial by oblique ridges running outward and backward. Epibranchial posterior and
Type. - The type species of Tetracarcinus Weller, anterior ofmesobranchial with subparallel ridges.
1905 is Tetracarcinus subquadratus Weller, 1905 Subtle ridges parallel gastrocardiac groove along by original designation. Weller described Tetra- outer edges from epibranchials to orbits. Chelae
and in carcinus subquadratus in 1905a (figs. 4, 5, 6) equal, large, triangular cross section, spiny; palm and again in 1905b (same figs, but with 5 & 6 slightly longer than high, oblique; fingers long, reversed). Four specimens were figured in 1907 slightly downturned, toothed.
(pi. Ill, figs. 16, 17, 18, and 19) and probably
- The available to Roberts (1962), first revisor, who Types. type species of Avitelmessus is designated the specimen illustrated by Weller, 1907, Avitelmessus grapsoideus Rathbun, 1923. The holo-
fig. 17 (NJSM #7788) and refigured by Rathbun, type of Avitelmessus grapsoideus is USNM #31895,
1935 (pi. 10, fig. 16) as the best preserved of the a male from Hudlers Landing, Cape Fear River,
“three syntypes”, now to be considered the lecto- 30 1/2 miles above Wilmington, North Carolina. type.
Range. - Avitelmessus is known from the Peedee
Range. — Tetracarcinus subquadratus is well known Formation of North Carolinaand is one of the most from the Northern Atlantic Coastal Plain from the common crabs on the eastern Gulf Coastal Plain,
Downloaded from Brill.com10/11/2021 12:22:01PM via free access Contributions to Zoology, 67 (4) - 1998 245
of Tetracarcinus Outer Fig. 2. 1, Dorsal view of complete carapace subquadratus from the Coon Creek Formation, Mississippi. 2,
view of right propodus interpreted to be referable to Tetracarcinus subquadratus from the Coon Creek Formation, Mississippi. 3,
of ofSeorsus the Coon Creek view of Dorsal view carapace wadei from Formation, Mississippi. 4, Dorsal nearly complete carapace
of Avitelmessus from the Formation, Ventral view of female young grapsoideus Ripley Mississippi. 5, nearly complete cephalolhorax
showing sternum and abdomen of Avitelmessus grapsoideusfrom the Pedee Formation, North Carolina. Scale bars equal 1 cm.
being known from Georgia and Alabama, and being with small central tubercle; metabranchial region
extremely abundant in the Mississippi Embayment, with subtle transverse and submarginal ridges.
ranging into Texas. It is found in late Campanian Claws and legs unknown.” (Bishop, 1988a: 72.)
and early Maastrichtian sediments.
Type. - The type species of Seorsus is Seorsus
- Included species. Only the type species is known. wadei Bishop, 1988, by original designation. The
holotype of Seorsus wadei (GSUM 1694) is
deposited in the collection of the Georgia Southern
Seorsus Bishop, 1988 University Museum, Statesboro, Georgia 30460-
(Fig. 2.3) 8064.
Diagnosis. - “Carapace of moderate size, longer Range. - Seorsus is known from North America
than wide (L/W = 1.10), widest at anterior 1/3; only from the early Maastrichtian of Mississippi.
lateral margins distinctively convergent posteriorly;
aerolations Included - The is the sole groovesbroad, moderately defined; very species. type species
cardiac of the tumid, especially epibranchial lobes; region representative genus.
Downloaded from Brill.com10/11/2021 12:22:01PM via free access 246 G.A. Bishop et al. - Late Cretaceous Dakoticancridae (Decapoda)
to and Systematic keys genera species
Carapace key
la Carapace circular, transversely flat, carapace regions
poorly differentiated, thin, spiny, large
Avitelmessus grapsoideus
lb Carapace quadrate or trapezohedral, arched, high,
carapace regions well differentiated, granulate, small
to medium-sized 2
2a Carapace trapezohedral, longer than wide
Seorsus wadei
2b Carapace quadrate; sides sub-parallel, sinuous, strongly
arched 3
than 3a Carapace wider long, sides converge posteriorly
Dakoticancer overanus
3b Carapace square or longer than wide 4
4a Carapace large, with inflated branchial chambers, pro-
minent posterior shelf Dakoticancer australis
4b Carapace small with granulate, metabranchial ridges
Tetracarcinus subquadratus
Chelipede key
la Propodus twice as long as high, granulate
Dakoticancer overanus
lb Propodus as long as high 2
2a Propodus smooth, bulbous, and small
Tetracarcinus subquadratus
2b Propodus not smooth 3
3a Propodus granulate DakoticancerI australis
3c Propodus spiny Avitelmessus grapsoideus
Cladistic analysis
Fig. 3. Data matrix and list ofcharacter states used in the cladistic
In to order test the of the genera within of of Dakoticancridae, relationships analysis genera the Dakoticancridae, a cladistic analysis was'
and designed run. The study employed PAUP 3.1.1 Because the number of taxa and the resulting to analyze the data matrix (Swofford, 1990). The data matrix was small, an exhaustive search was program was run on a Macintosh computer. performed. The search resulted in a total of 15
the for For Eight characters were selected as basis trees of which 5 were equally parsimonious.
developing the datamatrix (Fig. 3). These characters each, the consistency index was 1.000, the retention were those of the dorsal carapace and were selected index was 1.000, and the homoplasy index was because they reflected significant differences be- 0.000. tween the taxa and they were well enough preserved Examination of these five revealed that four of in each of the taxa to be measured. Each of the the trees shared the common character of placing characters reflected an aspect of the morphology Tetracarcinus at the base of the tree. As a result, of the crabs that was judged to be sufficiently and because Tetracarcinus is the first of the independent of the others that they would not be dakoticancrids to appear in the fossil record, the redundant. The which in which that hypothetical ancestor, against sole tree genus appeared to be more the taxa were featured, was assigned character states derived Was excluded from consideration. Using
be criterion of Judged to most primitive. the of order appearance in the fossil
Downloaded from Brill.com10/11/2021 12:22:01PM via free access Contributions to Zoology, 67 (4) - 1998 247
record of resulted in selection one tree (Fig. 4)
that realistically represents the arrangement of
genera within the family.
Paleoautecology
General
The morphology of crabs results from complex
patterns of development and adaptations to com-
plex physical and biological conditions. Schafer
four (1954) categorized groups of brachyuran
decapods as: 1) “Laufers auf dem Boden”, crabs
which crawl and run on the substrate surface, 2)
“des Grabens im Boden”, crabs which burrow into the sediment, 3) “des Kletterns auf zerkluftetem
Untergrund”, crabs which climb on vertical,
fissured, hard substrates, and 4) “des Schwimmens 4. inferred of within Fig. Cladogram showing relationships genera im freien crabs Wasser”, which swim in open the Dakoticancridae. waters. Each has a characteristic body plan enabling
the crab to move, to feed, to reproduce, and to
defend itself. The form of the body parts cons- teeth. Sometimes obvious conclusions can be made train the mode of life of the organism. Carapace about specific morphologies, but for most crabs and between shape proportions, angle sagittal plane the claws are tools for generalized many roles. and stemites, arrangementof stemites, lateral cross
and other in section, body aspects vary a general way with mode of life. Dakoticancer Paleoautecology of overanus
The carapace of “Laufers”, epifaunal crawlers,
is subquadrate, reflexed, with serrated or toothed The morphological characteristics ofDakoticancer front. The angle between the sagittal plane and overanus including its rectangular shape, long, the stemites is 76°. Stemites are somewhat radial slender equally-sized legs P2-P4, claws of similar relative to the to sagittal plane leading sideways size and held free from the shape carapace margin movements of the Lateral cross sections show legs. with modest-sized, small-toothed downturned that these crabs have a convex bottom with the fingers, and functional-sized corneas on the
embedded within the Chela are body legs. always eyestalks is consistent with the conclusion that fit formed so as to against the cephalothorax. Walk- Dakoticancer was a generalized epifaunal crawler ing legs become in forms and setose longer deep-sea that lived on the soft substrates ofthe mud bottoms with the weight borne by folding the dactyli over of the Western Interior Cretaceous Seaway. By “snow-shoes.” forming reduction of the hind-most P5, legs may be evidence The pincers, or chelae, of crabs serve multiple for a possible carrying and covering behavior functions and hence are highly variable in their exhibited by some modern crabs with reduced hind size and morphology. Those with specific functions legs. Dactyli on P2-P4 are elongate and triangular, may have longitudinal teeth, flat molari- shearing fully capable of folding over into “snow shoes”
; form crushing teeth, comb-like or club raking teeth, for walking across the soft substrate. Of all the like exterior for into shells. projections breaking observable characteristics, none can be cited which
Schafer (1954) discussed the morphology of chelae clearly establish the mode of life of this primitive of crabs and distinguished seven morphotypes of crab.
Downloaded from Brill.com10/11/2021 12:22:01PM via free access 248 G.A. Bishop et al. - Late Cretaceous Dakoticancridae (Decapoda)
P2-P4 and than the Dakoticancer overanus is associated with a few are subquadrate stout, longer
Not is wide. The of P5 concentrically layered straight burrows. only carapace last pair legs are
in are they not abundant enough to have been Dako- reduced and possibly carried a raised position.
ticancer domiciles, they are too small. The pre- The dactyli are triangular. The chelae are shorter
servation of burrows (probably assignable to the through the propodus, more robust, and more
thalassinoidProtocallianassa cheyennensis) in the granulated on their outer surface with fingers more
Dakoti- D. Dakoticancer assemblages indicates that if downturned than overanus and probably were
burrow its bur- of considerable No cancer overanus was a dweller, capable cutting pressure.
in have observed for rows would likely be preserved some abundance. epizoans been except one spec-
Because concluded imen attached its they were not, Bishop (1981) carrying an oyster to carapace.
that The of the Creek Dakoticancer overanus was not an obligatory lithology Coon indicates a shallow burrower. nearshore shelf habitat. Associated fossils of the
Creek facies include diverse and The consistent association ofDakoticancer over- Coon a very
normal anus with segmented burrows and fecal pellet abundant marine fauna, attesting to the
packed burrow trails led Bishop (1987: 325) to marine conditions of these sedimentary environ-
the conclusion that the and ments. The Dakoticancer australis from presence preservation assemblage of Dakoticancer overanus was linked through a the Coon Creek Formation of the Mississippi
positive feedback cycle to population explosions Embayment occurs in a muddy sandstone associated of benthic worm populations. If this conclusion is with abundant marine invertebrates including
benthic have been the and other valid, worms may preferred Exogyra, Sphenodiscus, Turritella, many
food item for Dakoticancer overanus, a conclusion invertebrates. Trace fossils include sparse Thalas-
further supported by this decapod’s delicate down- sinoides, leading to the conclusion thatD. australis
turned fingers armed with small teeth that would in the Coon Creek was not a burrow-dwelling deca-
in be useful capturing and pulling worms from the pod.
substrate. As with most crabs, Dakoticancer over- Dakoticancer australis assemblages from the
anus was not an obligatory feeder, but rather would Potrerillos Formation in Nuevo Leon, Mexico, were
have been a generalized omnivorous browser ca- found by Vega & Feldmann (1991) mainly in two
pable of rapidly responding to periodically burgeon- types of lithofacies. At one locality, molds were
ing food resources. found without any articulated appendages, with
Lithologic evidence from the bentonitic claystone carapace material very weakly preserved and of the Pierre Shale in which Dakoticancer over- frequently lost. The lithology is represented by light-
is in concretions with the the crabs anus preserved, usually phosphatic gray sandstone, layer containing
distributed through one to three meters of section situated one meter above a massive oestrid bank and the associated fauna including inoceramid composed by Pycnodonta mutabilis and Exogyra
bivalves, baculitid cephalopods, often diverse for- costata. The second locality comprises a fine- aminiferal suites (over 100 species at some local- grained lithology, with a great diversity of mollus-
and all indicate Dakoticancer infaunal bivalves. ities) mosasaurs, can species preserved, mainly
Burrows overanus lived in brackish to fully marine water filled with brown sandstone are con-
within of the Western Interior Cretaceous Seaway. spicuous the rather gray sandy shales. Here,
molds of D. australis were found inside galleries
with 7 12 diameters ranging from to cm. These
Paleoautecology of Dakoticancer australis crab remains, inferred by Vega& Feldmann (1991)
to be exuviae, are preserved within burrows and
Dakoticancer australis from the Mississippi Em- have preserved appendages that remain articulated,
is similar in but show dislocation of the ventral side of the bayment to D. overanus gross mor-
but with than 20 of phology significantly larger, more robust, carapace. To date, more specimens D.
a higher, more strongly ridged carapace that is more australis have been collected at this locality, all
granulated and with a thicker cuticle. Pereiopods within galleries and with dislocated plastrons. This
Downloaded from Brill.com10/11/2021 12:22:01PM via free access 67 - 1998 Contributions to Zoology, (4) 249
suggests a molting behavior within burrows, a legs that could have been useful in occasional in- behavior uncommon for most brachyurans, as cursions onto the supratidal zone.
molting inside burrows has not been observed
frequently in extant crabs (Vega & Feldmann,
1991). Nevertheless, D. australis specimens from Paleoautecology of Avitelmessus grapsoideus
the Cardenas Formation in San Luis Potosí, east-
central Mexico, and those from the Coon Creek The morphological characteristics of.Avitelmessus
of the include Mississippi Embayment, are not found grapsoideus an unusually large size, a
associated with burrows, and most of them showed carapace which is large, oval, and armored with
articulated appendages. It is possible that the spines along the front margin, long, flattened
in with of difference the molting behavior between as- appendages rows sharp spines along the
semblages of Nuevo León and San Luis Potosí dorsal edges, equant and very spiny chelipedes with teeth occlusional reflect different taphonomic histories, rather than cutting on surfaces, deeply in- cised orbits with divided different molting behavior (Vega et ah, 1995). It large eyestalks, orbits with between, broad is also important to note that the mean size of the trough compact antennules, a
mouthframe with broad maxilli- specimens from San Luis Potosí is bigger than the spatulate third pedes, and large mandibles. mean size reported for the Poterillos and Coon Morphologically, Avi- telmessus is Creek Formations. However, the dakoticancrids grapsoideus especially unusualbecause it is ofMaastrichtian from Mexico significantly larger than other North deposits are sparse, any American Cretaceous crab and its cross-sectional compared to some localities of the United States,
shape is flat, suggesting these animals inhabited a such as the Coon Creek Formation, where Bishop unique niche, perhaps sheltering by tightly pressing (1986a) reported 637 specimens, compared to no their flattenedbodies against the mud-sandbottoms more than 80 specimens of this species that had
on which lived on the shallow shelf. In been collected in the Potrerillos and Cardenas they addition
to a flattened with the carapace spines on dorsal Formations. Once again, we must consider dif- shield margin, Avitelmessus also is patterned and ferences in paleoenvironment, taphonomic histo- counter-shaded. One specimen from North Carolina ries, preservational histories, and collecting biases is encrusted with bryozoans on its legs, but not its to explain such differences in size and number of
carapace nor venter. individuals. Most samples, both from Potrerillos Avitelmessus is known from a few specimens and Cardenas Formations are exuviae, evidenced in North Carolina (holotype plus 13 specimens) by the displaced position of plastron and/or the and great numbers (i.e., of altered of the thousands) specimens height carapace. Bishop (1981:401, in the Mississippi Embayment and Eastern Gulf fig. 13-12) has observed similar squashing pheno- of Mexico. The pattern of distribution and local mena resulting in sternal displacement and tele- abundance of Avitelmessus grapsoideus suggests scoping of the carapace and sternum, pointing out crab that this was opportunistic and of that these the capable rapid phenomena may be result of cuti- fluctuations in size population in response to as cle weakening of the pleural suture during either undetermined yet ecological parameters. Avitel- exuviation or of Most decomposition a corpse. sam- messus grapsoideus is usually found in muddy from Nuevo León those found ples (except pre- lithologies, muddy sands of the Ripley Formation served within burrows) show disarticulated append- in the Eastern Gulf and Mississippi Embayment ages suggesting some transportation in a low-energy associated with abundant marine invertebrates and It environment. is possible that D. australis was a in papery shale at Graham, Mississippi, and from crawler in the intertidal zone, feeding on some the muddy sandstones of the Peedee Formation of mollusks, breaking their shells with rather strong North Carolina where it is associated with marine chelae. In fact, compared to other fossil crabs from vertebrates and invertebrates. the Maastrichtian of and northeastern, southern, All of these attributes led to the conclusion that east-central Mexico, D. australis seems to have Avitelmessus was an opportunistic crab that lived the heaviest and with robust strongest carapace, epifaunally as a “Laufer” on muddy-sand bottoms,
Downloaded from Brill.com10/11/2021 12:22:01PM via free access 250 G.A. Bishop et al. - Late Cretaceous Dakoticancridae (Decapoda)
feeding omnivorously most ofthe time but capable the Upper Cretaceous Pierre Shale ofSouthDakota. of exploiting rapidly expanding local food The decapod-dominated assemblages are preserved
this crab in resources. Locally, probably inhabited apatite concretions distributed through thin inter-
and of 7 that continuous the very nearshore lagoonal habitats. vals shale (3 to m) are over
1500 As large areas (15 to km ). decapods were
thin buried as molts and/or corpses, the interseg-
Paleoautecology of Tetracarcinus subquadratus mental membranes rapidly decomposed allowing
the decaying corpses to be filled by mud. The
Tetracarcinus subquadratus is a diminutive crab organic-rich sediment was ingested by deposit-feed-
evidenced filled and with a small, highly sculptured and granulated ing organisms as by open
and burrows and and of fecal carapace that is relatively rectangular high ubiquitous masses strings
standing. Orbits are deeply inset and rimmed by a pellets (Bishop, 1975). Compression due to weight
turberculate ridge, eyestalks thin and fold back ofoverburden flattened, broke, and rearranged parts
into outer orbital fossae. Pereiopods are still poorly of some decapods. Concentration of phosphates
in the fecal combined with the chemical known, preserved ischium? and merus? on one spec- pellets
imen are thin and round. Chelae are equant, carpus micro-environments of the enclosed spaces within
massive in dorsal aspect, quite long and stout, the crabs causing the precipitation of the apatite anterior surface granulate. Claws with enlarged concretions led to preservation of the decapods. bulbous propodi and thin fingers. Tetracarcinus The uniformity of distribution, uniformity of faunal
subquadratus is unusual because of its diminutive composition, and uniform mode of preservation
size, seldom larger than ca. 13 mm in width, con- of the faunas led to the conclusion that they are
trasting rather sharply with Dakoticancer and the the preserved portions of recurrent decapod com-
giant Avitelmessus. The small size of this animal munities. and the specialized claws, particularly the tweezer- The Dakoticancer community was dominated
like indicate was the crab Dakoticancer ba- pincers, may Tetracarcinus by overanus (75.0%),
adapted to a specialized mode of life, perhaps as culitid cephalopods and inoceramidbivalves. Less
an epizoan on plants or animals such as sponges. common preserved taxa are the decapods Homo-
This hypothesis remains unsubstantiated by data lopsis punctata (0.8%); Necrocarcinus pierrensis at this time. These crabs are associated with a (7.6%); Raninella oaheensis (0.3%); Sodakus ta- relatively normal marine fauna. Tetracarcinus is tankayotankaensis (0.1%); Zygatrocarcinus men-
in the common crab the Merchantville Formation dryki (0.05%); Palaeonephrops browni (0.4%); and of the C & D Canal on the Delmarva Peninsula Protocallianassa cheyennensis (0.5%) as well as and is a secondary element in the Dakoticancer numerous gastropods, bivalves, non-baculitid australis assemblage from the Coon Creek For- cephalopods, foraminifera, ostracodes, bony fish,
mation of the Mississippi Embayment in Union sharks and reptiles. The decapod-dominated com-
County, Mississippi. Only one specimen is known munity, theDakoticancer association, periodically
from the Western Interior Basin, that from the Lewis inhabited the Western Interior Cretaceous sea bot-
Shale ofWyoming. Tetracarcinus is unknown from tom when conditions in the unstable environment
the Gulf Coastal Plain west of the Mississippi were favorable. Populations of the crabs, repre-
Embayment. senting opportunistic species, colonized the bot-
tom over favorable areas. When conditions became
unfavorable (for yet unknown reasons) the crab
Dakoticancroid crab assemblages populations declined to previous low levels. The
periodic explosion of crab populations were thus
described the Decapod-dominated assemblages were superimposed upon stable, equilibrium popula-
by Bishop (1981, 1983c) in terms of associated tions of mollusks that characterize the typical fossil
taxa, distribution, and mode of preservation. He assemblages of the Pierre Shale. During non-fav-
collected (1981) described ca. 5,000 fossil decapods orable times the faunal elements of the Dakoti-
localities from six at five stratigraphic levels in cancer association were random elements pre-
Downloaded from Brill.com10/11/2021 12:22:01PM via free access Contributions to Zoology, 67 (4) - 1998 251
served in the molluscan assemblages. During favo- rable times the crab populations rapidly increased and became dominant and their record overprinted
the molluscan assemblages.
data The accumulated suggest that crab as-
semblages may represent opportunistic species of capable rapid population growth, perhaps to ex-
ploit burgeoning worm populations, followed by
a less rapid decline as a positive taphonomic short
cycle becomes operative (Bishop, 1986b; Bishop
& These Williams, 1986; Bishop, 1987). op-
crab “communities” in portunistic seem many cases
to be overprinted on “normal” molluscan thanato-
coenoses or biocoenoses (Bishop, 1986b). The process that led to the preservation of the decapod-
dominatedfaunas (Bishop, 1986a, 1986b) is thought
to havebeen initiated by aberrant and destabilizing
physicochemical conditions (like volcanism) that exterminated most living organisms, resulting in
nutrient the a flood onto and into substrate. This 5. of of Fig. Stratigraphic ranges species dakoticancrids ar-
flood of nutrients was exploited by an explosion rayed by biogeographic provinces. of worm populations providing a resource oppor-
tunity for organisms capable of harvesting the abundance of worms. The decapod crustaceans, science unless large collections are made.
in small were suited to always present numbers, Interpretations based on these different types of
the food the could exploit resource provided by worm records easily distort our understanding of communities and underwentpopulation explosions the geologic history of the decapods. in the response to resource availability provided
by the worms. As death took decapods back into
the substrate, they in turn provided an opportunity Origin of the Dakoticancridae
for extension of the worm community providing a
feedback of decreasing system worms-decapods- The oldest known species within the Dakotican- It is unknown if the worms-decapods-etc. decapod cridae is Tetracarcinus subquadratus from the fractions described Northern community (= assemblages) by Atlantic Coastal Plain (Fig. 5). Tetra- but in small Bishop were always present numbers carcinus subquadratus occurs in the late Santonian
if that formed or, they represent assemblages only through the mid-early Campanian. In the Mississippi
times of maximal resource during supply. Embayment Tetracarcinus subquadratus occurs in Two of records the types paleobiogeographic are early Maastrichtian. One specimen has been
thus defined, one based on the fortuitous described from presence the early-late Campanian of of remains in molluscan in decapod assemblages Wyoming the Western Interior (Bishop, 1986a). will be limited in numbers of Dakoticancer (which always spec- australis is found in abundance in imens and taxa) and another based on the Coon Creek Formation of Maastrichtian periodic age of blossoming opportunistic species of decapods in Mississippi, from the Maastrichtian of Texas, that may form fossil assem- and from Mexico. decapod-dominated Dakoticancer overanus has been
This if would blages. observation, true, mean that collected from the mid-Campanian to Maastrichtian the geological record of of opportunistic decapod spe- the Western Interior in great abundances from cies would be better than that of equilibrium Dakoticancer spe- assemblages described by Bishop cies, which wouldbe randomelements preserved as (1981). Avitelmessus grapsoideus is found in the in molluscan assemblages and easily Tost’ to Maastrichtian Peedee FormationofNorth Carolina
Downloaded from Brill.com10/11/2021 12:22:01PM via free access 252 G.A. Bishop et al. - Late Cretaceous Dakoticancridae (Decapoda)
(Bishop and Sturgeon in prep.) and the late western margin was the source of coarse elastics
Campanian to Maastrichtian Ripley and CoonCreek deposited in rapidly prograding deltaic complexes of the Eastern Gulf Coastal Plain. into rapidly subsiding basins, resulting in a com-
plex series of clastic wedges. Farther to the east
the Western Interior Seaway was a stable platform
Cretaceous Paleogeography which received the suspended fine elastics from
the western part of the basin and surrounding low-
General lying hills of eastern North America deposited as
thick units of mudstone and resulting in classic
with Kauffman (1977) has presented a model of Creta- interfmgering patterns coarser elastics to the
Cretaceous. ceous paleogeography and paleoclimatology as the west as tectonism pulsed throughout the for the and supercontinent ofPangea broke up and the Atlantic Paleocurrent patterns Tethys Seaway
the the Western Interior were Ocean opened. A circum-equatorial ocean, Seaway presented by
Tethys Seaway, dominatedworld paleogeography, Kauffman (1977: fig. 10) in assessing distribution
the stretching across America, northern Africa, and of larvae throughout basin.
southern Europe into the Paleo-Indian Ocean (where The interfmgering Cretaceous lithosomes also
volcanic ash from volcanos India was still a drifting subcontinent). Branching received air-transported off this east-west ocean were several north-south in the tectonically active Rocky Mountains to the
epicontinental seaways including the Western west, resulting in deposition of numerous layers
the bottom. Interior Seaway and the Northern Atlantic Seaway, of bentonite on Cretaceous sea These both stretching from the Tethys northward into the isochronous, pyroclastic events must have dramati-
paleo-Arctic Ocean. The Western Interior Seaway cally altered bottom conditions, water chemistry,
was characteristically a shallow, epicontinental sea- and atmospheric conditions, leading to dramatic
little more than a hundred meters in Cretaceous and biotas. As way, perhaps changes ecosystems
Western In- deep while the northern Atlantic was a true oceanic Laramide tectonism progressed, the from the area floored by oceanic crust extruded along the terior Basin was inundated by sediment
mid-Atlantic Ridge as the ocean basin opened by west causing progradation of large deltas and
sea floor spreading. The Atlantic Ocean was cer- restriction of the basin in Maastrichtian time to a
oceanic of less small Paleocene centered in North tainly a deeper, more body water remnant sea
the of local climate and tectonic the Cannonball Sea. prone to vagaries Dakota,
activity. Within this setting the primitive decapods The Cretaceous sediments of the Western Interior
underwent several radiations and extensive and major adaptive carry beautifully preserved faunas,
formed the lineages leading to modern decapod primarily encased in concretionary limestone
faunas. nodules. These faunas include rapidly evolving
cephalopod molluscs such as Baculites, Didymo-
other which ceras, Hoploscaphites, and many taxa
Western Interior Seaway have been developed into a well-documented chro-
nology based on faunal succession, bentonite stra-
The Western Interior Seaway as described by tigraphy, and radiometric dating. This chronology allows and such Kauffman (1977) is a complex epicontinental sea other physical biologic events, as
of to extending about 4,800 km from Arctic Canada to periodic appearances decapod Lagerstatten,
the Tethys Seaway and approximately 1,600 km be precisely dated.
its in wide from a mobile belt along western edge
Nevada and Utah to a stable shallow shelf along
its east side. Within this basin, water depths were Mississippi Embayment
variable and are inferred by Kauffman (1977) to
have been in the order of 100 value The is a Late Cretaceous m, a accepted Mississippi Embayment
by most Cretaceous workers. Other authors cite and Tertiary seaway that extended from the Tethys
much deeper conditions (Eicher, 1969). The active Seaway northward into southern Illinois as a well-
Downloaded from Brill.com10/11/2021 12:22:01PM via free access Contributions to Zoology, 67 (4) - 1998 253
defined depositional trough characterized by shal- Mexico have been reported for the Maastrichtian low shelf conditions and relative tectonic stability sediments of the Difunta Group (Vega & Feld-
et Resultant sediments consist (Russell ah, 1982). mann, 1991) and Cardenas Formation (Vega et ah, of shelf chalks and muddy chalks and nearshore 1995). elastics of basal sands, and consisting gravels, The Difunta Group is an Upper Cretaceous-Eo- sands. Within these sediments of muddy (Stephen- cene sequence terrigenous rocks, located in the
& son Monroe, 1940) are contained well-known states of Coahuila and Nuevo Leon. Two deltaic
faunas of the Selma Chalk, Ripley Formation, and systems prograded from the west and northwest, the Coon Creek Formations, including several filling the Parras and La Popa basins (McBride et extensive faunas Blue decapod from Springs, Mis- ah, 1974). Although Maastrichtian dakoticancrid
Coon and sissippi; Creek, Tennessee; Braggs, crabs seem to be more abundant in the shallow Alabama. calcarenites and sandstones of the La Popa basin,
some specimens have beencollected recently from
the Parras basin. Deposited north of the structural
Northern Atlantic Coastal Plain front of the Sierra Madre Oriental, the Difunta
Group was affected by a system of NW-SE faults.
The of in history the geological study of Cretaceous Diapirs the La Popa basin were the result of
of the Northern Atlantic Coastal Plain deformation and deposits plastic pressure over the underlying reviewed was by Owens et ah (1970). Geologic Minas Viejas anhydrites. It is probable that this studies of these rocks have been low hampered by feature resulted in local subsidence and basin-filling dense thick relief, vegetative cover, soils, repeated episodes, which prevailed until early Eocene times of and facies, poor preservation invertebrates, many (Vega et ah, 1989). Uplift of the Sierra Madre other factors. Data and diagrams presented by Oriental took place through the Late Cretaceous;
Owens et ah indicate the Late Cretaceous sediments thus, depositional basins of the Difunta Group were thin southward and units before some pinch out bordered by this feature to the south and southeast, the Delmarva reaching Peninsula leaving the by the Coahuila Platform to the northand northwest,
Merchantville, Englishtown, Marshalltown, and and by the Tamaulipas arch to the east and northeast
Mount Laurel Sand (oldest to youngest) represent- (McBride et ah, 1974).
series of clastic and litho- ing a calcareous clastic The southernmost occurrence of dakoticancrid
in somes deposited nearshore environments along crabs has been recorded from the sandstones and the Ocean. western margin of the opening Atlantic shales of the Maastrichtian Cardenas Formation, These sediments the Delmarva Peninsula have along on the eastern margin and central portion of the
and yielded a diverse abundant decapod fauna Sierra Madre Oriental, in San Luis Potosi state collected from soil by Flarry Mendryk dredging (Vega et ah, 1995). The Cardenas Formation com- exhumed from the & Delaware Canal reefal facies in Chesapeake prises the southern part of its the the during 1970’s, mostly assignable to early exposure area (Myers, 1968), while to the north it Merchantville Formation. Campanian becomes more terrigenous, with an almost uniform
of fine lithology sandstones and shales. Terrigenous
material was supplied from the west, from the rising Western Coastal Plain and Mexico occidental Gulf margin of Mexico. Uplift of the Sierra
Madre Oriental during the Late Cretaceous formed The of the depositional history Western Gulf a barrier to the east, thus deposition of Cardenas
Coastal Plain and Mexico the Late Creta- sands and muds during took place in an elongated, nearly ceous was similar to that for the Western north-south very corridor-shaped lagoon. Farther east, Interior Northeastern Mexico was domi- sediments of the Mendes Seaway. pelagic Formation were nated deltaic by prograding systems through deposited beyond this barrier, onto the GulfCoastal
Campanian and Maastrichtian time. Deposition of Plain. sediments and local subsidence ofbasins produced The Difunta Group and Cardenas Formation have
1000 thicknesses to m. Dakoticancrid crabs from up closer faunal affinities with rocks of the Mississippi
Downloaded from Brill.com10/11/2021 12:22:01PM via free access 254 G.A. Bishop et al. - Late Cretaceous Dakoticancridae (Decapoda)
Embayment thanwith correlative units of southwest conclusion is supported by the disjunct, fragmentary
Texas. The Campanian-Maastrichtian Aguja For- record of fossil decapods. Ofthe 97 known Creta-
of 42 mation comprises an eastward-thinning series ceous decapods from North America, species
each paralic and marine sandstones interbedded with are known from a single specimen, 8 species
3 shale and lignite deposited in a coastal plain envi- are represented by 2, and 4 specimens, and 3
Two 6 and 7 ronment. progradational cycles are represented species each are represented by 5, speci-
in these As 9 deposits (Lehman, 1986). a difference mens. Only 18 species are represented by or more with Mexican of the preservational style specimens, specimens and of these only 4 are represented by
from the Bend area are decapods Big phosphatized 100 or more specimens. These data suggest that
of related to the exuviae species more closely fossil decapods are scarce and our knowledge of
Interior Western fauna. then our decapod them is very incomplete. If this is true,
knowledge of their stratigraphic and geographic
distribution be fortuitous and random must very Dakoticancrids Biogeographic range of (in the sense of being useful for analysis). With
this limitation in mind it must be emphasized that, Three major biogeographic patterns of occurrence however limited the geologic record, it must be of the dakoticancrids are discernable; each domi- considered in evolutionary and paleoecologic stud-
nated a and discrete by genus having relatively ies. boundaries and each with a few known outside
Tetracarcinus occurrences. The occurrences of sub-
References quadratus are largely confined to the Northern At-
lantic Coastal Plain and the Mississippi Embay-
Bishop, G. A., 1974. A sexually aberrant crab (Dakoticancer ment with one specimen also known from Wyom- Pierre overanus Rathbun, 1917) from the Upper Cretaceous ing. Avitelmessus grapsoideus is found dominantly Shale of South Dakota. Crustaceana, 26: 212-219. in the Mississippi Embayment and Eastern Gulf Bishop, G. A., 1975. Traces ofpredation. In: R. W. Frey (ed.), Coastal Plain but is also known from North Caro- The study oftrace fossils: 261-281 (Springer Verlag, New lina. Dakoticancer is endemic to the West- overanus York). australis is ern Interior Seaway and Dakoticancer Bishop, G. A., 1981. Occurrence and fossilization of the abundant in the Mississippi Embayment but is also Dakoticancer assemblage, Upper Cretaceous Pierre Shale,
South Dakota. In; J. Gray et al. (eds.), Communities ofthe present in northeastern Mexico. Theseranges might past: 383-413 (Hutchinson Ross Publishing Company, be extended by additional collecting, but the co- Stroudsburg, PA). herenceof their distributions has remainedrelatively Bishop, G. A., 1983a. A second sexually aberrant specimen constant for a significant time, leading us to believe of Dakoticancer overanus Rathbun, 1917, from the Upper distributions real the are biogeographic pattern's, Cretaceous Dakoticancer assemblage, Pierre Shale, South
not artifacts of collecting biases. Dakota (Decapoda, Brachyura). Crustaceana, 44: 23-26.
Bishop, G. A., 1983b. Fossil decapod crustaceans from the
Late Cretaceous Coon Creek Formation, Union County,
Mississippi. J. crust. Biol., 3: 417-430. Interpretation Bishop, G. A., 1983c. Fossil decapod crustaceans from the
Lower Cretaceous Glen Rose Limestone ofCentral Texas. The Cretaceous decapods of North America occur Trans. S. Diego Soc. nat. History, 20: 27-55. either as 1) uncommon remains in molluscan fossil Bishop, G. A., 1984a. Paleobiogeography and evolution of
assemblages, 2) as common remains in molluscan- the Late Cretaceous crabs of North America, 1976-78. Nat.
dominated fossil assemblages, or 3) as dominant Geogr. Soc. Res. Rep., 17: 189-201.
Orbital bulla A elements in the Dakoti- Bishop, G. A., 1984b. reticularis: new orbital decapod assemblages, e.g.,
structure of a Cretaceous crab. J. crust. Biol., 4: 514-517. cancer assemblage described by Bishop (1981). Bishop, G. A., 1986a. Occurrence, preservation, and biogeog- The of occurrence fossil decapods as rare or occa- raphy of the Cretaceous crabs ofNorth America. Crusta- sionally common elements in molluscan assem- cean Issues, 4: 111-142.
has led to the conclusion that the blages logical Bishop, G. A., 1986b. Taphonomy of the North American record of is This geological decapods very poor. decapods. J. crust. Biol., 6: 326-355.
Downloaded from Brill.com10/11/2021 12:22:01PM via free access Contributions - to Zoology, 67 (4) 1998 255
Bishop, G. A., 1987. Positive feedback in North taphonomic Owens, J. P., J. P. Minard, N. F. Sohl & J. F. Mello., 1970. American Tethyan Cretaceous decapod-worm associations Stratigraphy of the outcropping Post-Magothy Upper Cre- In: K, McKenzie (ed.). Shallow Tethys2: 319-329 (Balkema, taceous Formations in southern New Jersey and northern Rotterdam). Delmarva Peninsula, Delaware and Maryland. U. S. geol. Bishop, G. A., 1988a. A new crab, Seorsus from the wadei, Survey prof. Pap., 674: 1-60. Late Cretaceous Coon Creek Formation, Union County, Rathbun, M. J., 1917. New species of South Dakota Creta- Mississippi. Proc. biol. Soc. Wash., 101: 72-78. ceous crabs. Proc. U.S. nat. Mus., 52: 385-391. Bishop, G. A., 1988b.New fossil crabs, Plagiophthalmus izetti, Rathbun, M. J., 1923. Decapod crustaceans from the Upper Latheticocarcinus and shapiroi, Sagittiformosus carabus Cretaceous of North Carolina. North Carolina geol. Sur- (Crustacea, from the Western Interior Creta- Decapoda), 5: 403-407. vey, ceous, U.S.A. Proc. biol. Soc. Wash., 101: 375-381. Rathbun, M. J,, 1926, Decapoda. In: B. Wade (ed.). The fauna Bishop, G. A. & A. B. Williams., 1986. The fossil lobster of the Ripley Formation on Coon Creek, Tennessee: 184- Linuparus canadensis, Carlisle Shale (Cretaceous, Tura- 191 (U.S. geol. Survey prof. Pap., 137). Black Hills. Nat. 2: nian), geogr. Res., 372-387. Rathbun, M. J., 1935. Fossil Crustacea of the Atlantic and Eicher, D., 1969. Paleobathymetry of Cretaceous Greenhorn Gulf Coastal Plain. Geol. Soc. Am. 2: 1-160. spec. Paper, in Colorado. sea eastern Am. Assoc. Pet. Geol. Bulletin, Rathbun, M. J., 1937. Cretaceous and tertiary crabs from 53: 1075-1090. Panama and Colombia. J. Paleontol., 11(1): 26-28. Feldmann, R. M. & P. A. Maxwell., 1990. Late Eocene deca- H. 1962. The Roberts, B., Upper Cretaceous decapod crusta- pod Crustacea from north Westland, South Island, New ceans of New Jersey and Delaware. In: H. G. Richards Zealand. J. Paleontol, 64: 779-797. The (ed.), Cretaceous fossils of New Jersey: 163-191 (New Glaessner, M. F., 1960. The fossil decapod Crustacea of New Bureau of Jersey Geology and Topography, Bull. 61). Zealand and the evolution of the Order Decapoda. New Russell, E. E., D, M. Ready, E. A. Mancini & C. E. Smith, Zealand Geol. Survey Paleontol. Bull., 310: 1-63. 1982. Upper Cretaceous in the Lower Mississippi Embay- Glaessner, M, F., 1969. Decapoda, In: R. C. Moore (ed.), Trea- of ment Tennessee and Mississippi. Lithostratigraphy and tise on invertebratepaleontology. Part R, Arthropoda, 4(2): biostratigraphy: 1-50 (Earth Enterprises, Inc.). 400-651 (Univ. Kansas Press, Lawrence). Schafer, W., 1954.Form und Funktion der Brachyuren-Schere, Glaessner, M. F., 1980. New Cretaceous and Tertiary crabs Abh. senckenb. naturforsch-Ges., 489: 1-65. from Australia and New Zealand. Trans. R. Soc. S. Aust,
Stephenson, L. W. & W. H. 1940. The Creta- 104: 171-192. Monroe, Upper
ceous deposits. 40: 1- D., 1977. nouvelle classifica- Mississippi geol. Survey Bulletin, Guinot, Propositions pour une 296. tion des Crustaces Decapodes. C. r. hebd. Seanc. Acad. Swofford, 1990. PAUP; Sci., 285: 1049-1052. Phylogenetic analysis using parsi- version mony, 3.0 (disc). Illinois nat. Hist. Survey Guinot, D., 1978. Principles of a new classification of the (Cam- paign, Illinois). Crustacea Decapoda Brachyura. Bull. biol. Fr. Belg., 3; F. J, & R. M. 211-292. Vega, Feldmann, 1991. Fossil crabs (Crustacea,
Decapoda) from the Maastrichtian Difunta North- Guinot, D., 1993. Donnees nouvelles sur les Crabes primitifs Group, eastern Mexico. Ann. 60: 163-177. (Crustacea Decapoda Brachyura Podotremata). C. r, hebd. Carnegie Mus., Vega, F. J,, R. M. Feldmann Seanc. Acad. Sci., Ser. Ill, Sciences de la Vie/Life Sci- & F. Sour-Tovar, 1995. Fossil crabs 316: (Crustacea: the Late ences, 1225-1232. Decapoda) from Cretaceous Cardenas Kauffman, E. G., 1977. Geological and biological overview: Formation, east-central Mexico. J. Paleontol.,
69: Western Interior Cretaceous Basin. In: E. G. Kauffman 340-350.
(Spec. Ed.), Cretaceous facies, faunas, and paleoenviron- Vega, F, J., L. M. Mitre-Salzar & E. Martinez-Hernandez, 1989. Contribution ments across the Western Interior Basin. The Mountain al conocimientode la estratigrafia del Grupo Difunta Geologist, 14(3&4): 75-99. (Cretacico Superior-Terciario) en el No-
de Kesling, R. V. & 1, G. Reimann, 1957. An Upper Cretaceous reste Mexico. Mexico, Universidad Nacional Autonoma,
Institute de crab, Avitelmessus grapsoideus Rathbun. Contrib, Mus. Geologia. Revista, 8: 179-187.
Paleontol., 14: 1-15 (Univ. Michigan). Weller, S., 1905a. The fauna ofthe Cliffwood (N. J.) Clays
Lehman, T. M. 1986, Late Cretaceous sedimentation in Trans- J. Geol., 13: 324-337.
Pecos Texas. West Texas Soc. Bull., 25: 4-9. Weller, S., 1905b. The fauna of geol. the CliffwoodClays. Annual E. A. E. McBride, F., Weidie, J. A. Wolleben & R. C. Lau- Report of the State Geologist for the Year 1904. Geol. don, 1974. Stratigraphy and structure ofthe Parras and La Survey of New Jersey: 133-144.
Popa basins, northeastern Mexico. Geol. Soc. Am. S., 1907. A Bull., Weller, report on the Cretaceous paleontology of 84 1603-1622. (10): New Jersey. Geol. Survey of New Jersey, Paleontological R. Myers, L., 1968. Biostratigraphy of the Cardenas Forma-' Survey IV: 846-853.
tion (Upper Cretaceous), San Luis Potosi, Mexico. Pale-
ontol. 24: 1-89. Mexicana, Received: 8 February 1998
Downloaded from Brill.com10/11/2021 12:22:01PM via free access