Biogenic Sedimentary Structures Produced by Architectonica laevigata (Gastropod: Architectonicidae), Mandvi Intertidal Zone, Gulf of Kachchh, Western India

Abstract Biogenic structures of Architectonica laevigata (Gastropod: Architectonicidae) were studied along the lagoon of the Modwa spit area, Mandvi, Gulf of Kachchh. The traces are bilobed in cross-section, forming complex meandering trails, while their burrows are closely packed small holes about 1-2 mm in diameter. The traces are produced during low tides and are concentrated in specific areas within the intertidal zone, and also show substrate preference. These traces and burrows are intimately associated with each other, which reflect their behaviour modification to avoid steep thermal gradients and desiccation stress during low tide conditions in the lagoon and intertidal area. Similar traces are comparable with the ichnogenera Gyrochorte and Scolicia, which are abundant from Precambrian times to recent. Such traces, if preserved, serve as a good indicator for paleo-environmental conditions

Infaunalization and resource partitioning during the Mesozoic marine revolution

Infaunalization has been regarded as representing a response to increased predation pressures and is therefore central to the Mesozoic marine revolution, which gives pre-eminence to the role that enemy-directed evolution has played as a driving force of biotic change. Our ichnologic compilation from 39 Middle Triassic to Late Jurassic shallow-marine siliciclastic units allows us to evaluate the vertical partitioning of the infaunal ecospace through the application of the ichnoguild concept. This study shows that infaunal communities experienced a marked increase in ecospace utilization during the Early Jurassic, reaching a plateau during the rest of the Jurassic. This trend is expressed by an increase in the maximum number of ichnoguilds per community and per tier and in the number of ichnotaxa per ichnoguild. This pattern shows important partitioning of the infaunal ecospace into a series of tiers and that several organisms were able to exploit the same resources available at discrete sediment zones below the sea bottom. The increase in the maximum number of ichnoguilds per community and per tier suggests that niche partitioning was a key factor in a more efficient use of the infaunal ecospace and in driving alpha diversity. However, the increase in the number of ichnotaxa per ichnoguild indicates that ichnoguilds were packed with organisms exploiting similar resources, arguing against the role of competitive exclusion in structuring communities. Because several episodes of predation increase took place during the Mesozoic, an unequivocal link between predation pressures and infaunalization cannot be demonstrated empirically.Fil: Buatois, Luis Alberto. University of Saskatchewan; Canadá. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Mángano, M. Gabriela. University of Saskatchewan; CanadáFil: Desai, Bhawanisingh. Pandit Deendayal Energy University; IndiaFil: Carmona, Noelia Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; ArgentinaFil: Burns, Fiona. Firmground; AustraliaFil: Meek, Dean. University of Saskatchewan; CanadáFil: Eglington, Bruce. University of Saskatchewan; Canad

Dwarf megateuthidid belemnites from the Bathonian of Kachchh (India: Gujarat) and their significance for palaeobiogeography

<p>We describe in detail new finds of dwarf megateuthidid belemnites from the Middle–Late Bathonian of Kachchh (Western India), previously only rarely mentioned in the literature. The material is assigned to a new genus and species, <i>Challinoria challinori</i> gen. et sp. nov. Extensive morphological comparison together with analysis of the biogeographical distribution of comparable taxa suggests affinity of the newly described taxon with Early Bajocian megateuthidids from South America, showing the existence of a previously unknown megateuthidid habitat area in the Southern Hemisphere during the Bajocian and Bathonian. The biogeographical patterns and trans-equatorial migration routes of Middle Jurassic megateuthidids are discussed. The occurrence of the newly described taxon in the Bathonian of India, along with the lack of Mediterranean and Indo-Pacific records of similar age, may be connected with the short-term opening of a marine trans-Gondwanan seaway.</p> <p><a href="http://zoobank.org/References/urn:lsid:zoobank.org:pub:F5F7B7E6-ABA2-4EAF-A56C-9025075428A0" target="_blank">http://zoobank.org/References/urn:lsid:zoobank.org:pub:F5F7B7E6-ABA2-4EAF-A56C-9025075428A0</a></p

On Two Interesting Marine Crabs (Decapoda: Brachyura) from Mandvi, Kutch

Volume: 101Start Page: 184End Page: 18

Opportunistic colonizers in the Kallankurichchi Formation, Cauvery Basin, South India: Implications on Maastrichtian environmental stress

International audienc

Terrestrial Martian Analog Heritage of Kachchh Basin, Western India

The Kachchh Basin is a peri-cratonic rift basin in western India, exposing a vast range of diverse geologic features representing the past 200 million years spanning from the Jurassic Period to the recent. The Basin represents highly rugged terrain in the form of the hilly ranges and pediment surfaces, while the flat terrain in the north is expressed by the low-lying Rann and Banni plains (mudflats, marshes, and grassland). This basin has preserved several classical terrestrial analog sites to study planetary science. Several potential localities in the basin provide opportunities to explore as Martian analogs. In the present study, we have proposed five analog sites from the Kachchh basin that has preserved classical geomorphic feature (volcanic and impact craters) as well as minerals (primary phyllosilicates, secondary hydrous sulfates, precipitated iron minerals, evaporite, and liquid brines like perchlorates) that tell the tale of the geological activity taken place on the Mars. The cultural and ecological aspects of the proposed sites and their hinterland are also discussed for the tourist attractions. All the proposed sites have ample geoheritage potential and need strong attention for conservation. Further, the establishment of geoparks and development of geotourism in the proposed area will enhance the Earth and Planetary Sciences scenario apart from boosting of local economy, including helping activities, research funding, and employment opportunities for locals that will play a significant role in the economic development of the region. To achieve such an ambitious program and accomplish the Sustainable Development Goals, these locations should be conserved and extended for geotourism