Latest Cretaceous to earliest Paleogene molluscan faunas of New Zealand : changes in composition as a consequence of the break-up of Gondwana and extinction

Uppermost Cretaceous (Campanian?-Maastrichtian) to lowermost Paleogene (Paleocene) rocks of New Zealand contain an exceptional record of Bivalvia, Gastropoda and Scaphopoda. The composition of these faunas is closely linked with the separation of New Zealand from the East Antarctic-Australian sector of Gondwana, development of open oceanic conditions by Early Campanian time (c. 80-85 Ma), and Cretaceous-Tertiary boundary extinctions. This work aims to: 1) document the changes in paleobiogeographic elements (endemic, paleoaustral, Indo-Pacific/Tethyan, and cosmopolitan) of molluscs across the K-T interval; 2) provide a quantitative analysis of the Weddellian Biotic Province hypothesis of Zinsmeister (1979), which has resulted in a refined biogeographic model for the Gondwana Realm; and 3) examine the extent and effect of the terminal Cretaceous extinction event on the Mollusca of New Zealand. This study recognises 329 species of latest Cretaceous to earliest Paleogene molluscs from New Zealand. Of these, 118 new species are described in the systematic catalogue together with comments on their inferred feeding habits. Previously established species are refigured and where justified, redescribed and taxonomically updated. Of 329 species, 159 are of latest Cretaceous age (Piripauan to Haumurian stages) and 170 are Paleocene ("Wangaloan" or Teurian). A total of 79 bivalve, 47 gastropod and 2 scaphopod genera/subgenera are recognised in the Late Cretaceous record, with 35 bivalve, 76 gastropod and 3 scaphopod comparable taxa from the Paleocene. New genera/subgenera proposed in the systematics section are Brookula (Paleobrookula n. subgen.) (Skeneidae), Kaiparomphalus n. gen. (Trochidae), Saulopsis n. gen. (Tudiclidae), Wangaluta n. gen. (Volutidae), Wangacteon n. gen. (Acteonidae), and Kaurueon n. gen. (Acteonidae). Thirty-four new combinations are proposed. Zelandiella Finlay, 1926, is synonymised with Austrocominella von Ihering, 1907. Conchothyra marshalli (Trechmann, 1917) is considered as distinct from C. parasitica Hutton, 1877. The following species-group synonymies are proposed: Bittiscala communis Finlay and Marwick, 1937, with~- simplex (Marshall, 1917); Conchothyra expedita Finlay and Marwick, 1937, with C. australis (Marshall, 1916); Euspira lateaperta (Marwick, 1924) with Euspira fyfei (Marwick, 1924); and Campylacrum debile Finlay and Marwick, 1937,with C. sanum Finlay and Marwick, 1937. Though the biostratigraphic resolution of uppermost Cretaceous and Paleocene New Zealand rocks has improved recently, problems still exist in correlating some macrofossil localities because of rarity of index microfossils, facies faunas, and incomplete knowledge of stratigraphic ranges of some taxa. Thus, Piripauan (Campanian? Maastrichtian?) and Haumurian (Maastrichtian) stages are virtually inseparable in the field and laboratory. At Wangaloa, southeastern Otago, a K-T boundary section appears to be present c.10 m below the shell beds. Reintroduction of the abandoned Wangaloan Stage may be appropriate, pending further microfossil work, as the relationship of this stage to the very long (c. 8 m. y.) Teurian Stage could be established. Molluscan faunas at Wangaloa and elsewhere in South Island can be correlated to the lower part of the dinoflagellate Palaeocystodinium qolzowense Zone, indicating a late Early Paleocene age. A macrofossil zone, Zeacolpus (Leptocolpus) semiconcavus Assemblage-zone, is proposed for widespread molluscan-rich Paleocene faunas of South Island. Compared to other Austral sequences, New Zealand has an excellent record of latest Cretaceous to earliest Paleogene molluscs. Dramatic compositional changes across this interval ultimately reflect the break-up of Gondwana and environmental perturbations on shallow shelf faunas. Endemism in New Zealand latest Cretaceous molluscs was weak (c. 8% of genera/subgenera), but increased substantially (c. 32%) by Paleocene time, partially reflecting the geographic and genetic isolation of "greater New Zealand" at this time. The paleoaustral component, including endemics herein, was also relatively weak (c. 21%) during the Cretaceous but marked (c. 60%) by the Paleocene. The IndoPacific/ Tethyan and cosmopolitan components decreased from c. 48% to c. 26% and c. 26% to c. 12% across the interval, respectively. Few cosmopolitan Late Cretaceous species and endemic genera/subgenera of this age have been recorded. Most Late Cretaceous taxa are endemic species of cosmopolitan or wide-ranging genera/subgenera (c. 92%). The Paleocene fauna is entirely endemic at species-level, apart from possible records of Cucullaea (Cucullona) inarata Finlay and Marwick, 1937, from the Paleocene of southeastern Australia and Taieria allani Finlay and Marwick, 1937, from the Paleocene of Chatham Islands. High similarity coefficient values (≤ 0.76; Simple, Dice and Simple Matching) of latest Cretaceous and Paleocene molluscan genera/subgenera from New Zealand, Chatham Islands, Australia, New Caledonia, Antarctic Peninsula and southern South America, indicate strong faunal links between these areas during the latest Cretaceous. Such links corroborate the Weddellian Province hypothesis. The marked homogeneity of these widespread faunas probably reflects large shelf area, a low sea-surface temperature gradient, and favourable oceanic circulation including perhaps a trans-Antarctic seaway during the latest Cretaceous. Sea-surface temperatures across the K-T boundary were probably subtropical to at least warm temperate in New Zealand. The New Zealand Subprovince of the Austral Province (Kauffman, 1973) should be abandoned because of the low endemic component of New Zealand molluscs during the Late Cretaceous. For the Paleocene only New Zealand and southeastern Australia have significantly similar faunas (Simpson similarity indices: 0.36- bivalves, 0.91-gastropods). In the Paleocene, the Weddellian Province probably was reduced to the New Zealand-southeastern Australia and possibly Chatham Islands region along the newly opened Tasman Sea. New Zealand data are consistent with the idea that gradual environmental changes resulting from the final fragmentation of Gondwana, coupled with a probable bolide impact(s) in lower latitudes, caused mass extinction and suppressed biomass productivity, but was followed by faunal rebound during the Early Paleocene. In this study the latest Maastrichtian – earliest Danian time interval could not be resolved enough to identify any low diversity "disaster fauna" above the K-T boundary. The magnitude, however, of the extinction can be gauged along with the extent of the inferred initial radiation phase. In total, about 39% and 36% of bivalve genera/subgenera and gastropods became extinct at the end of the Cretaceous in New Zealand. All New Zealand species recorded in uppermost Cretaceous rocks became extinct sometime during the late Maastrichtian and earliest Danian. The extinction at genus-level was not as severe as in other areas including North Africa, Atlantic Coastal Plain, and northern Europe. The extinction particularly affected infaunal and epifaunal suspension feeders (c. 89%), fewer epifaunal herbivores and browsers (c. 65%), and negligible carnivores and deposit feeders. Data support the idea that the K-T event was selective against suspension feeders and that there was diminished productivity of phytoplankton at the base of the food chain. About 50% of latest Cretaceous molluscs, including Lazarus taxa, crossed the K-T boundary. Most survivors were seemingly eurybathyal with recorded species in a spectrum of shelf settings. Approximately half of Paleocene survivors were infaunal suspension feeders, but few were epifaunal. Most gastropod survivors were carnivores and deposit feeders. Significantly, Paleocene survivors and presumed new taxa became extinct during the Paleocene (c. 27%). Gamma (total) species diversity changed little across the K-T boundary indicating that diversity quickly recovered in the first few million years after the extinction. Bivalve diversity decreased substantially over the K-T interval, whereas gastropod diversity climbed. This “flip-flop” in diversity indicates that gastropods outpaced bivalves during the early Tertiary and could help explain the veritable burst of radiation in inferred "bloom" families (e. g. N.e.ticidae, Turridae, Acteonidae). The "Wangaloan" fauna probably characterises rapid evolution in isolation and an initial phase of radiation reflecting high speciation in which many new groups filled the ecological vacuum left by the extinction, followed by a further less severe extinction pulse in late Danian time

Comment on the letter of the Society of Vertebrate Paleontology (SVP) dated April 21, 2020 regarding “Fossils from conflict zones and reproducibility of fossil‑based scientific data”: Myanmar amber

Non peer reviewe

Labor And The Politics Of Structural Adjustment In Australia And Indonesia

The labour forces of Australia and Indonesia are compared for the period from the late 1960s to the 1990s. The position of labour in a global economy is also considered. It is determined that the outlook for organised labour is bleak, however its position is also contingent upon national circumstance

Patterns of biodiversity and faunal rebound following the K-T boundary extinction event in Austral Palaeocene molluscan faunas

Palaeocene molluscan faunas are characterised by complex evolutionary histories following the Cretaceous–Tertiary (K–T) boundary extinction event and exhibit dramatic, distinct signatures of composition and biodiversity levels relating to extinction and post-extinction recovery processes. This paper is the first to document and survey the entire Palaeocene record of the Southern Hemisphere, which comprises at least 515 recorded molluscan taxa from Australia, New Zealand/Chatham Islands, Antarctica, and South America. The record is much richer than previously recognised. The K–T boundary event was a prime mechanism of change for the composition of Palaeocene faunas, but Palaeocene diversity patterns were shaped also by the final break-up of Gondwana, concomitant changes in climate and in oceanic circulation, and faunal recovery processes. The ‘flip-flop’ in diversity of bivalves and gastropods across the K–T boundary stems from a rapid, evolutionary burst of speciation in the Danian for gastropods, especially carnivorous forms with planktotrophic development, which infilled ecospace vacated by the extinction. In the Southern Hemisphere fossil record, deposit feeders were less affected by the extinction event and seemingly more extinction-resistant, but other important factors related to stratigraphic range and spectrum of life habits/habitats affected survivorship success. Suspension feeders, especially epifaunal forms, were hard hit by the extinction, but had bounced back within a few million years by late Danian time at the latest, but at lower diversity than during the Late Cretaceous. The extinction was not as marked in most southern regions, as reflected in the Antarctic record. In the Antarctic K–T boundary interval, diversity drops suddenly ca 50 m before the boundary, and while suspension feeders remain at low diversity for at least 300 kyr, gastropods still dominate the molluscan assemblages. Most of the K–T boundary molluscan survivors were bivalve species (66%) and all of these were members of representative genera that displayed extensive stratigraphic and geographic ranges in the Cretaceous or earlier in the Mesozoic. The majority of earliest Danian Antarctic molluscs belong to newly evolved species within surviving genera (58%), but by late Danian time this trend had changed to a dominance of new species in new genera. Many new groups arose during the Palaeocene, especially by late Danian time, and these faunas are highly distinctive at both genus and species level. For example, the Wangaloa Formation fauna of late Danian age (ca 63–61 Ma) is dominated by new species in new genera, ranging in values from 62.5 to 81%. A systematic catalogue of all known Palaeocene Austral species is presented herein in the Appendix for the first time with details of formation recorded, age, and inferred life habits

Diversity, distribution, and evolutionary history of the Austral, Late Cretaceous to Eocene, gastropod Struthioptera (Stromboidea: Aporrhaidae)

The prominently alate and sculptured marine gastropod, Struthioptera (Caenogastropoda: Stromboidea: Aporrhaidae) appeared in the New Zealand region at the latest during the early Cenomanian (early Late Cretaceous). Struthioptera campiveta n. sp., from the Marlborough region, is the first member and likely progenitor of the group, but no potential ancestor to Struthioptera has been recovered from Lower Cretaceous rocks. Concomitantly with the final separation of the Gondwana fragments in the latest Cretaceous, species-level diversity of Struthioptera climbed and the group diverged into at least four coeval species by this time: S. haastiana in the New Zealand region; S. novoseelandica in both New Zealand and Chatham Islands; S. pastorei in southern Argentina, Patagonia; and S. smiti in the Antarctic Peninsula region.? protuberatus from the Late Cretaceous of Patagonia may also belong here. The Cretaceous-Tertiary (K-T) boundary extinction crisis reduced the genus to a single representative, S. osiris, in the early Danian (late Early Paleocene) in New Zealand, and its probable descendant, S. camachoi, from the Middle-Late Eocene of Antarctic Peninsula. Shell size in Struthioptera increased markedly over the K-T boundary and the group became extinct in the Late Eocene, probably as a result of marked temperature changes near the Eocene/Oligocene boundary. Presented here is the first detailed review of Struthioptera since the first specimen was collected at Wangaloa, South Island, New Zealand, in late 1868 or early 1869. Species of Struthioptera are inferred to have been epifaunal and/or semi-infaunal deposit feeders and rather gregarious marine snails in sandy facies along the shallow shelf

Early evolutionary history of Monalaria (Mollusca: Gastropoda: Struthiolariidae) from the Palaeogene of New Zealand

The endemic and short-lived struthiolariid gastropod, Monalaria, is one of the most widespread marine molluscs of upper lower to middle Eocene shelf deposits in New Zealand. A new shallow shelf species, Monalaria poliveta n. sp., described herein from the Five Forks Glauconitic Sands Member of the Kauru Formation dated as Mangaorapan to Heretaungan in age (late early to early middle Eocene, c. 55-50 Ma), is the oldest recorded member of the genus.\ud \ud Monalaria is represented by only three Eocene species, M. poliveta n. sp., M. gracilis Finlay & Marwick, 1937 (Porangan? Stage, middle middle Eocene), and M. concinna (Suter, 1917) (Bortonian Stage, late middle Eocene), after which time it became extinct along with several other molluscan groups. These taxa show a strong affinity with the latest Cretaceous struthiolariid, Conchothyra marshalli (Trechmann, 1917), from Haumurian Campanian?-Maastrichtian) deposits of the South Island. Conchothyra marshalli is the most likely candidate to be the progenitor of the Monalaria stock, despite a gap of approximately 10 Ma in the fossil record of these two biostratigraphically significant groups

Macropalaeontology of the Trochocyathus-Trematotrochus band (Paleocene/Eocene boundary), Dilwyn Formation, Otway Basin, Victoria

Our limited knowledge of latest Paleocene and earliest Eocene Australian macrofaunas is much reduced with the report here of 37 species of invertebrates and vertebrates from coastal outcrops of the Dilwyn Formation in the Otway National Park, Victoria. The Trochocyathus-Trematotrochus band in the lowermost part of the Dilwyn Formation has yielded the highest taxonomic diversity in the formation, with 29 species of shallow marine bivalves, gastropods and scaphopods, along with less common brachiopods, echinoderms and cnidarians, and sparse vertebrate remains (shark teeth, otoliths). At least seven (possibly ten) molluscan species are common to the underlying Pebble Point Formation. Four new species are the gastropods Drepanocheilus (Tulochilus) retisurus sp. nov., Cerithiella leptopyrga sp. nov., Volutomitra (Waimatea) dilwyni sp. nov. and Mauidrillia otwayensis sp. nov. Eight probably new taxa are: Euspira? sp. nov., Nassaria? sp. nov., Odostomia? sp. nov.?, Circulus sp. nov.?, Proximitra sp. nov. cf. P. trirugulata Darragh, 1997, Microvoluta? sp. nov., Dentalium? sp. nov.? and Trematotrochus sp. nov. All macroinvertebrate species are, on present knowledge, endemic to Victoria, with the exception of Parvamussium sp. which is known from Western Australia

Geological exploration of Cockburn Island, Antarctic Peninsula

Cockburn Island is one of the most historically significant places on the Antarctic continent. The isle was first surveyed in early 1843 during Captain James Ross' famous expedition, but the early explorers failed to recognise its geological and palaeontological significance.\ud \ud Cockburn Island is exceptional for it has the only succession of Upper Cretaceous, Eocene and Miocene-Pliocene rocks on the continent, which is now known to contain an admirable and diverse fossil record of fauna and flora.\ud \ud These fossil assemblages are providing exciting new information on the evolutionary history of Antarctica. At least 22 species of Late Cretaceous macroinvertebrates and vertebrates have been recognised, whereas the Eocene record is slightly more diverse at 28 macroinvertebrate taxa recorded.\ud \ud The Pliocene macrofossil record is depauperate at some 11 species, but microfossils (diatoms, ostracods, foraminifera) are represented by at least 94 taxa. The palaeoecologic and palaeobiogeographic significance of fossil assemblages is explored in this paper. Further, a checklist of fossils is presented herein, for the first time, as is a bibliography of the geology and palaeontology of the island

A new gastropod mollusc, Antarctissitys austrodema gen. et sp. Nov., from the upper Maastrichtian of Antarctica and its evolutionary significance

The Maastrichtian López de Bertodano Formation of Seymour Island, Antarctic Peninsula, hosts the most diverse assemblage of Late Cretaceous molluscs from the continent. Described here is a new genus and species of gastropod, Antarctissitys austrodema gen. et sp. nov., from the upper units of the formation, which are inferred to represent a mid-shelf clastic environment. Antarctissitys austrodema is assignable to the Perissityidae (Muricoidea) and is the first confirmed record of this family in the Southern Hemisphere, indicating a much more widespread Cretaceous geographic distribution. Fusus dusenianus Wilckens from the Upper Cretaceous of Patagonia and Perissitys? sp. from the Maastrichtian of New Zealand may also belong in Perissityidae, but preservational deficiencies prevent any firm assessment. The affinities of Antarctissitys gen. nov. lie with a diverse suite of perissityid taxa in the Upper Cretaceous of North America, belonging predominantly to Perissitys