Dale Tshudy

Evolutionary patterns in macrurous decapod crustaceans from Cretaceous to early Cenozoic rocks of the James Ross Island region, Antarctica

Abstract The fossil record of macrurous decapod crustaceans is unusually rich in the Late Cretaceous to Paleocene rocks of the James Ross Island region, Antarctica. Four species of lobsters, contained in four genera, are known from the region. Hoploparia stokesi (Weller) is most abundant and has been collected on James Ross, Vega, Humps, Cockburn, Seymour, and Snow Hill islands from early Campanian through Paleocene rocks. Whereas morphometric analysis of the species shows no evolutionary trends in shape, carapace ornamentation and claw ornamentation become more variable higher in the section. Metanephrops jenkinsi Feldmann, has also been identified. Metanephrops has previously been known from only one fossil occurrence, in the Pliocene of New Zealand. Its occurrence on Seymour Island may lie within the region of origin of this taxon which currently inhabits deep water, lower latitude habitats in the Atlantic and Indo-Pacific oceans. Metanephrops jenkinsi is known in the early Campanian Santa Marta Formation, in the Maastrichtian portion of the Lopez de Bertodano Formation, and in the Paleocene Sobral Formation. Other taxa are less abundant. In early to middle Campanian rocks on James Ross Island, Meyeria crofti Ball represents a relatively late occurrence of a conservative group. Linuparus macellarii Tshudy & Feldmann represents the highest latitude occurrence of a species within this genus, which is known from numerous Cretaceous and Paleogene sites in the Northern Hemisphere but from only two other fossil occurrences in the Southern Hemisphere. This species ranges from the early to middle Campanian into the Paleocene. There is no apparent effect of the K/T boundary ‘event’ on the decapod fauna. New taxa appear below the K/T boundary and none of the Antarctic species disappear from the record at that time.

Morphology-Based Phylogenetic Analysis of the Clawed Lobsters (Family Nephropidae and the New Family Chilenophoberidae)

ABSTRACT The phylogeny of extinct and extant clawed lobsters is interpreted using a morphology-based phylogenetic analysis. Twenty-one genera, representing two clades, are grouped into either the redefined family Nephropidae or the new family Chilenophoberidae. Chilenophoberids, the primitive sister group of nephropids, share a close common ancestry with members of the Erymidae, and arose by the Middle Jurassic. Nephropids arose by the Early Cretaceous. Among clawed lobsters, no one morphological character is generally more reliable than any other as a guide to phylogeny. Homoplasy in aspects of groove pattern, ornamentation, and the appendages is widespread. The ubiquity of homoplasy in lobster evolution argues against the practice of erecting suprageneric taxonomic groups based on a few, intuitively selected characters. Cretaceous lobsters strongly resemble Recent ones, and no long-term, directional evolutionary trends were detected.

Cephalopods; biasing agents in the preservation of lobsters

-Two species of the heteromorph ammonite genus Diplomoceras Hyatt are described from the Upper Cretaceous of the James Ross-Seymour Islands area, Antarctica. The late Campanian-early Maastrichtian D. lambi Spath has a relatively high rib density, whereas D. maximum n. sp. has a lower rib density and is known only from the uppermost Maastrichtian of the Lopez de Bertodano Formation on Seymour Island. Both species attain an exceptionally large size with the body chamber of D. maximum n. sp. attaining a length in excess of one meter. The structure of the shell wall in Diplomoceras is characterized by the thickening of the nacreous layer below the ribs. The shell thickening results in an inner flat surface and a smooth phragmocone. Reconstruction of the shell suggests at least four parallel shafts and three U-connectives. Estimates of the total density, center of buoyancy, and center of mass in this reconstructed shell indicate a slightly positive buoyant shell with a relatively unstable floating position. . Paleont., 63(5), 1989, pp. 626-636 pyright ? 1989, Th Pale ntological Society

PECTINATE CLAWS IN DECAPOD CRUSTACEANS: CONVERGENCE IN FOUR LINEAGES

Abstract Decapod crustaceans bearing major claws with long, slender fingers armed with pectinate (comblike) denticles have been described in six genera arrayed within three families (Polychelidae, Nephropidae, and Ctenochelidae) in three infraorders (Palinura, Astacidea, and Anomura, respectively). Only one or a few genera in each infraorder exhibit this claw form. The pectinate claw form is confidently interpreted as having evolved independently in four lineages: once in the Polychelidae, once in the Ctenochelidae, and twice in the Nephropidae. Three of the lineages are known from both the fossil record and modern seas; the polychelid form is known only from Jurassic rocks. Convergence in this claw form developed to the extent that isolated fossil claws (i.e., claws without associated bodies) have commonly been misidentified at high taxonomic levels. The fossil record confirms what seems intuitively reasonable: that claw morphology is prone to convergence and should not, by itself, be given a high degree of taxonomic importance.

Ultrastructure in cuticle from Hoploparia stokesi (Decapoda: Nephropidae) from the Lopez de Bertodano Formation (Late Cretaceous-Paleocene) of Seymour Island, Antarctica

Examination, utilizing scanning electron microscopy, of 58 specimens of Hoploparia stokesi (Weller) from the Maastrichtian portion of the Lopez de Bertodano Formation, Seymour Island, Antarctica, leads to the conclusion that cuticular ultrastructure may be used to distinguish molted from deceased remains of nephropid lobsters. Molted cuticle is characterized by deterioration, or loss, of lamination in the inner endocuticle whereas cuticle, during the intermolt phase, exhibits lamination throughout the endocuticle as well as the exocuticle. Diagenetic effects may obscure lamination throughout the cuticle. These observations confirm that Salters position is typical of molted remains in fossils. Furthermore, partial remains of H. stokesi generally are molts. Preservational quality of molted remains tends to be better than that of corpses.

HOPLOPARIA, THE BEST-KNOWN FOSSIL CLAWED LOBSTER (FAMILY NEPHROPIDAE), IS A “WASTEBASKET” GENUS

Abstract Hoploparia McCoy, 1849 (Lower Cretaceous (Valanginian)–Miocene) is, by far, the most diverse clawed lobster genus (fossil or Recent); 49 species are known. The genus has been interpreted intuitively to be morphologically primitive and ancestral to some or many modern nephropid genera. Prior to the present study, two separate issues raised the suspicion that Hoploparia is a “wastebasket” genus—a default genus for any fossil lobster with a mainstream nephropid morphology. One issue is the difficulty in characterizing (i.e., coding) the morphology of Hoploparia, as a genus, for cladistic analysis. For Hoploparia, and far more than for other lobster genera, many characters show variable character states. A second issue is that the morphologies of some Recent genera (e.g., Eunephrops and Nephropides) seem easily accommodated within the fossil genus Hoploparia. Both issues stem from an originally ambiguous diagnosis of Hoploparia that has been variously expanded in de facto fashion to the point that, today, nobody really knows what Hoploparia means. Cladistic analyses herein indicate that Hoploparia is paraphyletic and, therefore, support the intuitive judgement that Hoploparia is a wastebasket genus. This paper, the first species-level cladistic analysis of Hoploparia, is not intended to be the sole basis for taxonomic revision but is, instead, intended to generate discussion among lobster specialists. Hopefully, this discussion will bring forth additional characters for cladistic analysis and other new insights that may lead to better supported cladograms addressing lobster taxonomy.

Morphology Based Cladistic Analysis of Metanephrops: The Most Diverse Extant Genus of Clawed Lobster (Nephropidae)

Abstract We performed the first cladistic analysis of Metanephrops, the most diverse extant genus of clawed lobster, using a morphology-based data matrix of all 20 species of Metanephrops and 35 cladistically informative characters, all external hard parts. Unweighted cladistic analysis corroborates previous studies that indicated that homoplasy is rampant in the evolution of clawed lobsters. Only 5 of the 68 synapomorphies identified by the analysis are unambiguous, unreversed synapomorphies. Recent species of Metanephrops have traditionally been divided (non-cladistically) into four morphology-based groups. Cladistic analyses support the traditional, arafurensis, Atlantic/binghami, and japonicus groupings; these groups are monophyletic. The thomsoni group is not supported by the cladogram. The (two) oldest known fossil Metanephrops species occur in Late Cretaceous, shallow marine rocks of the eastern/Atlantic side of the Antarctic Peninsula. The stratigraphic and geographic occurrences of these fossil species are the basis for the previously hypothesized, Late Cretaceous, southern high latitude origin of Metanephrops. Cladistic results corroborate that Metanephrops originated in the southern high latitudes. The cladistically most plesiomorphic single species, the recent M. challengeri, and the next most plesiomorphic species, the Late Cretaceous M. rossensis, are both known from the high southern latitudes. Likewise, the most plesiomorphic species group, the binghami group, is best known from the high southern latitudes.

JAGTIA KUNRADENSIS, A NEW GENUS AND SPECIES OF CLAWED LOBSTER (DECAPODA: NEPHROPIDAE) FROM THE UPPER CRETACEOUS (UPPER MAASTRICHTIAN) MAASTRICHT FORMATION, THE NETHERLANDS

Abstract A new genus and species of clawed lobster, Jagtia kunradensis, is described from the Upper Cretaceous (Upper Maastrichtian) Kunrade Limestone facies of the Maastricht Formation, The Netherlands. Three nephropid lobster genera and at least three species (Oncopareia bredai Bosquet, 1854, sensu Tshudy, 1993, Oncopareia sp. Tshudy, 1993, Hoploparia beyrichi Schlüter, 1862, and Jagtia kunradensis) have now been collected from limestones of the Maastrichtian type area (southeastern Netherlands and northeastern Belgium). Cladistic methods were employed in re-evaluating the phylogenetic relationships of the nephropid lobsters, including Jagtia. These analyses indicate that Jagtia is part of a clade that includes the recent Thymops and Thymopsis. The new genus is the first fossil form to be closely allied with these deep-water genera.

Infraorder Astacidea Latreille, 1802 p.p.: the marine clawed lobsters

This chapter overviews the state of knowledge of the biology and ecology, systematics and biogeography, and economic importance of the marine clawed lobsters. The lobster body plan, including a full description of external and internal morphology. It also reviews embryonic and larval development primarily derived from information on the wellstudied taxa. The status of lobster systematics, comparing phylogenies derived from both morphological and molecular methods. The abundant ecological and biogeographic information available for the shallow water, conspicuous species with the fragmentary information for the others to develop a synthetic view of the ecological factors influencing patterns in the distribution and abundance of modern marine clawed lobsters. Finally, overviews the economic importance of marine lobsters globally and identify taxa at risk of over-exploitation. Keywords:conspicuous species; ecological; marine clawed lobsters; morphological; phylogenies; shallow water

HOPLOPARIA ALBERTAENSIS, A NEW SPECIES OF CLAWED LOBSTER (NEPHROPIDAE) FROM THE LATE CONIACIAN, SHALLOW-MARINE BAD HEART FORMATION OF NORTHWESTERN ALBERTA, CANADA

Abstract A new species of clawed lobster, Hoploparia albertaensis, is reported from the late Coniacian, shallow-marine Bad Heart Formation of northwestern Alberta, Canada. Hoploparia is a well-known, clawed lobster genus with a record extending from Early Cretaceous (Valanginian) to Miocene. Fifty-one species of Hoploparia are known worldwide; 13 from the North American Western Interior Seaway. None of the 12 other Interior Seaway species, of any age, closely resembles the new species. The new species strongly resembles Hoploparia gabbi Pilsbry, 1901 from the upper Santonian–lower Campanian of the U.S. Mid-Atlantic Coastal Plain.