A Jurassic stem pleurodire sheds light on the functional origin of neck retraction in turtles

Modern turtles are composed of two monophyletic groups, notably diagnosed by divergent neck retraction mechanisms. Pleurodires (side-necked turtles) bend their neck sideways and protect their head under the anterior margin of the carapace. Cryptodires (hidden-necked turtles) withdraw their neck and head in the vertical plane between the shoulder girdles. These two mechanisms of neck retraction appeared independently in the two lineages and are usually assumed to have evolved for protective reasons. Here we describe the neck of Platychelys oberndorferi, a Late Jurassic early stem pleurodire, and find remarkable convergent morphological and functional similarities with modern cryptodires. Partial vertical neck retraction in this taxon is interpreted to have enabled fast forward projection of the head during underwater prey capture and offers a likely explanation to the functional origin of neck retraction in modern cryptodires. Complete head withdrawal for protection may therefore have resulted from an exaptation in that group

Families Bothremydidae, Euraxemydidae, and Araripemydidae.

698 p. : ill. (some col.), maps (1 col.) ; 26 cm.Includes bibliographical references (p. 657-672).Although pleurodires have been considered significantly less diverse than their sister group, the cryptodires, current discoveries show that pleurodires had a more complex and extensive evolutionary history than had been realized. Previously unknown radiations, particularly in the near-shore marine realm, are revealed by taxa with diverse cranial morphology, indicating many different feeding and sensory strategies. The pleurodire group that is changed the most by the new discoveries is its largest group, the hyperfamily Pelomedusoides. The hyperfamily Pelomedusoides now consists of the families Pelomedusidae, Podocnemididae, Bothremydidae, Araripemydidae, and Euraxemydidae, new family. The families Bothremydidae, Araripemydidae, and Euraxemydidae, new family, are documented with descriptions of skulls, lower jaws, and shells. The relationships of the family Podocnemididae to its sister taxa Hamadachelys and Brasilemys are recognized by placing them in the epifamily Podocnemidinura. The epifamily Podocnemidinura is the sister group to the family Bothremydidae, and together they form the superfamily Podocnemidoidea. The family Araripemydidae consists of one taxon, Araripemys barretoi, from the Aptian-Albian of Brazil. Description of new cranial material suggests that it is the sister group to all other Pelomedusoides or the sister group to the Pelomedusidae, but these relationships are only weakly supported. There is strong support for a multichotomy of Araripemys, Pelomedusidae, and remaining Pelomedusoides. Araripemys is characterized by very thin triturating surfaces and by a shell that lacks mesoplastra and has the first costals reaching the shell margin. The new family Euraxemydidae consists of two new genera: Euraxemys essweini, n. gen. et sp., from the Albian Santana Formation of Brazil, and Dirqadim schaefferi, n. gen. et sp., from the Cenomanian Kem Kem beds of Morocco. Members of the Euraxemydidae are united by the unique possession of a medial process of the quadrate partially covering the prootic and narrowly contacting a ventral process of the exoccipital, in contrast to all other pleurodires, which have either complete exposure or complete covering of the prootic ventrally. Furthermore, members have a ventral process of the exoccipital that is exposed at the lateral margin of the basioccipital in an elongate foot. The Euraxemydidae is hypothesized as the sister group to the superfamily Podocnemidoidea. The family Bothremydidae and the epifamily Podocnemidinura (consisting of the family Podocnemididae, Hamadachelys, and Brasilemys) are united as the superfamily Podocnemidoidea based on the possession of a quadrate-basioccipital contact, the complete or nearly complete ventral covering of the prootic, and the extension of the pectoral scales onto the entoplastron. The family Bothremydidae is a large and diverse group extending from the Albian to the Eocene in North and South America, Europe, Africa, and India. Its monophyly is supported by the presence of a wide exoccipital-quadrate contact, a eustachian tube separated from the incisura columellae auris usually by bone to form a bony canal for the stapes, absence of a fossa precolumellaris, a supraoccipital--quadrate contact (except in the tribe Taphrosphyini), and a posterior enlargement of the fossa orbitalis. Although there is a diversity of triturating surfaces within the family, primitively bothremydids have a posteriorly wide triturating surface with a significant palatine contribution in the upper jaw. The family Bothremydidae consists of four newly recognized, monophyletic groups: the tribes Kurmademydini, Cearachelyini, Bothremydini, and Taphrosphyini. The tribe Kurmademydini consists of two taxa: Kurmademys kallamedensis, from the Maastrichtian Kallamedu Formation of India, and Sankuchemys sethnai, from the Maastrichtian Intertrappean beds of India. The tribe Kurmademydini is characterized by extensive temporal and cheek emargination, a large fossa precolumellaris, and a small, anterior exposure of the prootic on the ventral surface. The tribe Kurmademydini is the sister group to the subfamily Bothremydinae (consisting of the tribes Cearachelyini, Bothremydini, and Taphrosphyini). Members of the subfamily Bothremydinae all possess a foramen stapedio-temporale that faces anteriorly. The tribe Cearachelyini consists of Cearachelys placidoi, from the Albian Santana Formation of Brazil, and Galianemys emringeri and Galianemys whitei, both from the Cenomanian Kem Kem beds of Morocco. The tribe Cearachelyini is characterized by a jugal retracted from the orbital margin and a fenestra postotica formed into a short slit. The tribe Cearachelyini is the sister group to the infrafamily Bothremydodda (consisting of the tribes Bothremydini and Taphrosphyini). The infrafamily Bothremydodda is characterized by a quadrate shelf formed below the cavum tympani, a foramen stapedio-temporale and foramen nervi trigemini that are very close together on the anterior face of the otic chamber, and a condylus occipitalis and occipital neck that are formed only by the exoccipitals. The tribe Bothremydini consists of Foxemys mechinorum, from the Campanian-Maastrichtian of France; Polysternon provinciale, from the Campanian of Europe; Zolhafah bella, from the Maastrichtian Dakla Formation of Egypt; Rosasia soutoi, from the Campanian-Maastrichtian of Portugal; Araiochelys hirayamai, n. gen. et sp., from the Danian phosphates of Ouled Abdoun Basin, Morocco; Bothremys cooki, from the Maastrichtian Navesink Formation of New Jersey; Bothremys maghrebiana, n. sp., from the Danian phosphates of Ouled Abdoun Basin, Morocco; Bothremys kellyi, n. sp., from the Ypresian phosphates of Ouled Abdoun Basin, Morocco; Bothremys arabicus, from the Santonian of Jordan; Chedighaii hutchisoni, n. gen. et sp., from the Campanian Kirtland Formation of New Mexico; and Chedighaii barberi, n. gen., from the Campanian of Arkansas, Alabama, Kansas, and New Jersey. The tribe Bothremydini is the sister group to the tribe Taphrosphyini. The tribe Taphrosphyini is characterized by the presence of a jugal-quadrate contact, the absence of a maxilla-quadratojugal contact, and the absence of a supraoccipital-quadrate contact. Members of the tribe Taphrosphyini have a considerable variety of triturating surfaces but they lack the wide, triangular surfaces typical of the other bothremydids. The tribe Taphrosphyini consists of Taphrosphys sulcatus, from the Danian Hornerstown Formation of New Jersey; Taphrosphys congolensis, from the Paleocene of Cabinda, west Africa; Taphrosphys ippolitoi, n. sp., from the Danian phosphates of the Ouled Abdoun Basin, Morocco; Labrostochelys galkini, n. gen. et sp., from the Danian phosphates of the Ouled Abdoun Basin, Morocco; Phosphatochelys tedfordi, from the Ypresian phosphates of the Ouled Abdoun Basin Morocco; Ummulisani rutgersensis, n. gen. et sp., from the Ypresian phosphates of the Ouled Abdoun Basin, Morocco; Rhothonemys brinkmani, n. gen. et sp., from the Paleogene phosphates of the Ouled Abdoun Basin, Morocco; Azabbaremys moragjonesi, from the Paleocene Teberemt Formation of Mali; Nigeremys gigantea, from the Maastrichtian of Niger; and Arenila krebsi, from the Maastrichtian Dakla Formation of Egypt. Among the Bothremydidae, the Taphrosphyini is the most diverse morphologically. The triturating surfaces show a wide range of variation. The long, narrow skull of Labrostochelys differs significantly from the very short skull of Phosphatochelys. Other genera, such as Azabbaremys and Arenila, have large and massive skulls, but without broadly expanded triturating surfaces, while Ummulisani has very narrow and deep labial ridges. The nasal regions of Taphrosphyini also show wide diversity. Rhothonemys has nasal openings and cavities more than twice the size of the orbits, but the nasal openings in Labrostochelys are smaller than the relatively small orbits. This diversity of Taphrosphyini skull morphology is mostly evident in the Paleogene of North Africa. A phylogenetic analysis of the core dataset of 41 taxa, 122 cranial characters, and 52 postcranial characters relies on comparative descriptions of these taxa. The analysis using PAUP results in one most parsimonious cladogram of 382 steps with a consistency index of 0.6. A Bremer decay analysis shows that the family Bothremydidae is strongly supported at five steps: the tribes Kurmademydini and Cearachelyini have an index of 2, and the tribe Taphrosphyini has an index of 3. The tribe Bothremydini becomes unresolved at one step and is the most weakly supported of these groups. The addition of selected shell-only taxa with low missing data values to the core dataset results in one equally parsimonious cladogram that is resolved as: (Proterochersis (Platychelyidae (Dortoka (Chelidae (Pelomedusidae + Araripemys) (Euraxemydidae (Teneremys (Podocnemididae + Hamadachelys + Brasilemys (Bothremydidae)))))))). A partitioned dataset consisting only of cranial characters (excluding all shell-only taxa) results in one equally parsimonious cladogram identical to the most parsimonious cladogram resulting from the whole dataset; however, a partitioned dataset consisting only of postcranial characters (excluding all skull-only taxa) resulted in 2704 trees, the consensus of which lacks resolution for nearly all Pelomedusoides, but which does resolve more basal pleurodires. When the skull morphology of the Bothremydidae is placed in the context of all other turtles, it becomes apparent that this family has the greatest range of skull forms of any turtle family yet known. In fact, the skull morphologies of many turtle families seem remarkably uniform in comparison (e.g., Testudinidae, Kinosternidae, Pelomedusidae, Trionychidae, Carettochelyidae)...There are other turtle families with bizarre skull morphologies (e.g., Nanhsiungchelyidae; Meiolaniidae) but these are not taxonomically diverse, at least as they are now known. In no other family do we see the extremes exemplified by the skulls of forms like Cearachelys, Bothremys, Labrostochelys, Azzabaremys, Rhothonemys, and Phosphatochelys. It is this remarkable variation in skull morphology that has allowed us to formulate a strong hypothesis of bothremydid relationships in spite of the presence in Pelomedusoides of remarkably uniform shells"--P. 6-8

Families Bothremydidae, Euraxemydidae, and Araripemydidae.

698 p. : ill. (some col.), maps (1 col.) ; 26 cm.Includes bibliographical references (p. 657-672).Although pleurodires have been considered significantly less diverse than their sister group, the cryptodires, current discoveries show that pleurodires had a more complex and extensive evolutionary history than had been realized. Previously unknown radiations, particularly in the near-shore marine realm, are revealed by taxa with diverse cranial morphology, indicating many different feeding and sensory strategies. The pleurodire group that is changed the most by the new discoveries is its largest group, the hyperfamily Pelomedusoides. The hyperfamily Pelomedusoides now consists of the families Pelomedusidae, Podocnemididae, Bothremydidae, Araripemydidae, and Euraxemydidae, new family. The families Bothremydidae, Araripemydidae, and Euraxemydidae, new family, are documented with descriptions of skulls, lower jaws, and shells. The relationships of the family Podocnemididae to its sister taxa Hamadachelys and Brasilemys are recognized by placing them in the epifamily Podocnemidinura. The epifamily Podocnemidinura is the sister group to the family Bothremydidae, and together they form the superfamily Podocnemidoidea. The family Araripemydidae consists of one taxon, Araripemys barretoi, from the Aptian-Albian of Brazil. Description of new cranial material suggests that it is the sister group to all other Pelomedusoides or the sister group to the Pelomedusidae, but these relationships are only weakly supported. There is strong support for a multichotomy of Araripemys, Pelomedusidae, and remaining Pelomedusoides. Araripemys is characterized by very thin triturating surfaces and by a shell that lacks mesoplastra and has the first costals reaching the shell margin. The new family Euraxemydidae consists of two new genera: Euraxemys essweini, n. gen. et sp., from the Albian Santana Formation of Brazil, and Dirqadim schaefferi, n. gen. et sp., from the Cenomanian Kem Kem beds of Morocco. Members of the Euraxemydidae are united by the unique possession of a medial process of the quadrate partially covering the prootic and narrowly contacting a ventral process of the exoccipital, in contrast to all other pleurodires, which have either complete exposure or complete covering of the prootic ventrally. Furthermore, members have a ventral process of the exoccipital that is exposed at the lateral margin of the basioccipital in an elongate foot. The Euraxemydidae is hypothesized as the sister group to the superfamily Podocnemidoidea. The family Bothremydidae and the epifamily Podocnemidinura (consisting of the family Podocnemididae, Hamadachelys, and Brasilemys) are united as the superfamily Podocnemidoidea based on the possession of a quadrate-basioccipital contact, the complete or nearly complete ventral covering of the prootic, and the extension of the pectoral scales onto the entoplastron. The family Bothremydidae is a large and diverse group extending from the Albian to the Eocene in North and South America, Europe, Africa, and India. Its monophyly is supported by the presence of a wide exoccipital-quadrate contact, a eustachian tube separated from the incisura columellae auris usually by bone to form a bony canal for the stapes, absence of a fossa precolumellaris, a supraoccipital--quadrate contact (except in the tribe Taphrosphyini), and a posterior enlargement of the fossa orbitalis. Although there is a diversity of triturating surfaces within the family, primitively bothremydids have a posteriorly wide triturating surface with a significant palatine contribution in the upper jaw. The family Bothremydidae consists of four newly recognized, monophyletic groups: the tribes Kurmademydini, Cearachelyini, Bothremydini, and Taphrosphyini. The tribe Kurmademydini consists of two taxa: Kurmademys kallamedensis, from the Maastrichtian Kallamedu Formation of India, and Sankuchemys sethnai, from the Maastrichtian Intertrappean beds of India. The tribe Kurmademydini is characterized by extensive temporal and cheek emargination, a large fossa precolumellaris, and a small, anterior exposure of the prootic on the ventral surface. The tribe Kurmademydini is the sister group to the subfamily Bothremydinae (consisting of the tribes Cearachelyini, Bothremydini, and Taphrosphyini). Members of the subfamily Bothremydinae all possess a foramen stapedio-temporale that faces anteriorly. The tribe Cearachelyini consists of Cearachelys placidoi, from the Albian Santana Formation of Brazil, and Galianemys emringeri and Galianemys whitei, both from the Cenomanian Kem Kem beds of Morocco. The tribe Cearachelyini is characterized by a jugal retracted from the orbital margin and a fenestra postotica formed into a short slit. The tribe Cearachelyini is the sister group to the infrafamily Bothremydodda (consisting of the tribes Bothremydini and Taphrosphyini). The infrafamily Bothremydodda is characterized by a quadrate shelf formed below the cavum tympani, a foramen stapedio-temporale and foramen nervi trigemini that are very close together on the anterior face of the otic chamber, and a condylus occipitalis and occipital neck that are formed only by the exoccipitals. The tribe Bothremydini consists of Foxemys mechinorum, from the Campanian-Maastrichtian of France; Polysternon provinciale, from the Campanian of Europe; Zolhafah bella, from the Maastrichtian Dakla Formation of Egypt; Rosasia soutoi, from the Campanian-Maastrichtian of Portugal; Araiochelys hirayamai, n. gen. et sp., from the Danian phosphates of Ouled Abdoun Basin, Morocco; Bothremys cooki, from the Maastrichtian Navesink Formation of New Jersey; Bothremys maghrebiana, n. sp., from the Danian phosphates of Ouled Abdoun Basin, Morocco; Bothremys kellyi, n. sp., from the Ypresian phosphates of Ouled Abdoun Basin, Morocco; Bothremys arabicus, from the Santonian of Jordan; Chedighaii hutchisoni, n. gen. et sp., from the Campanian Kirtland Formation of New Mexico; and Chedighaii barberi, n. gen., from the Campanian of Arkansas, Alabama, Kansas, and New Jersey. The tribe Bothremydini is the sister group to the tribe Taphrosphyini. The tribe Taphrosphyini is characterized by the presence of a jugal-quadrate contact, the absence of a maxilla-quadratojugal contact, and the absence of a supraoccipital-quadrate contact. Members of the tribe Taphrosphyini have a considerable variety of triturating surfaces but they lack the wide, triangular surfaces typical of the other bothremydids. The tribe Taphrosphyini consists of Taphrosphys sulcatus, from the Danian Hornerstown Formation of New Jersey; Taphrosphys congolensis, from the Paleocene of Cabinda, west Africa; Taphrosphys ippolitoi, n. sp., from the Danian phosphates of the Ouled Abdoun Basin, Morocco; Labrostochelys galkini, n. gen. et sp., from the Danian phosphates of the Ouled Abdoun Basin, Morocco; Phosphatochelys tedfordi, from the Ypresian phosphates of the Ouled Abdoun Basin Morocco; Ummulisani rutgersensis, n. gen. et sp., from the Ypresian phosphates of the Ouled Abdoun Basin, Morocco; Rhothonemys brinkmani, n. gen. et sp., from the Paleogene phosphates of the Ouled Abdoun Basin, Morocco; Azabbaremys moragjonesi, from the Paleocene Teberemt Formation of Mali; Nigeremys gigantea, from the Maastrichtian of Niger; and Arenila krebsi, from the Maastrichtian Dakla Formation of Egypt. Among the Bothremydidae, the Taphrosphyini is the most diverse morphologically. The triturating surfaces show a wide range of variation. The long, narrow skull of Labrostochelys differs significantly from the very short skull of Phosphatochelys. Other genera, such as Azabbaremys and Arenila, have large and massive skulls, but without broadly expanded triturating surfaces, while Ummulisani has very narrow and deep labial ridges. The nasal regions of Taphrosphyini also show wide diversity. Rhothonemys has nasal openings and cavities more than twice the size of the orbits, but the nasal openings in Labrostochelys are smaller than the relatively small orbits. This diversity of Taphrosphyini skull morphology is mostly evident in the Paleogene of North Africa. A phylogenetic analysis of the core dataset of 41 taxa, 122 cranial characters, and 52 postcranial characters relies on comparative descriptions of these taxa. The analysis using PAUP results in one most parsimonious cladogram of 382 steps with a consistency index of 0.6. A Bremer decay analysis shows that the family Bothremydidae is strongly supported at five steps: the tribes Kurmademydini and Cearachelyini have an index of 2, and the tribe Taphrosphyini has an index of 3. The tribe Bothremydini becomes unresolved at one step and is the most weakly supported of these groups. The addition of selected shell-only taxa with low missing data values to the core dataset results in one equally parsimonious cladogram that is resolved as: (Proterochersis (Platychelyidae (Dortoka (Chelidae (Pelomedusidae + Araripemys) (Euraxemydidae (Teneremys (Podocnemididae + Hamadachelys + Brasilemys (Bothremydidae)))))))). A partitioned dataset consisting only of cranial characters (excluding all shell-only taxa) results in one equally parsimonious cladogram identical to the most parsimonious cladogram resulting from the whole dataset; however, a partitioned dataset consisting only of postcranial characters (excluding all skull-only taxa) resulted in 2704 trees, the consensus of which lacks resolution for nearly all Pelomedusoides, but which does resolve more basal pleurodires. When the skull morphology of the Bothremydidae is placed in the context of all other turtles, it becomes apparent that this family has the greatest range of skull forms of any turtle family yet known. In fact, the skull morphologies of many turtle families seem remarkably uniform in comparison (e.g., Testudinidae, Kinosternidae, Pelomedusidae, Trionychidae, Carettochelyidae)...There are other turtle families with bizarre skull morphologies (e.g., Nanhsiungchelyidae; Meiolaniidae) but these are not taxonomically diverse, at least as they are now known. In no other family do we see the extremes exemplified by the skulls of forms like Cearachelys, Bothremys, Labrostochelys, Azzabaremys, Rhothonemys, and Phosphatochelys. It is this remarkable variation in skull morphology that has allowed us to formulate a strong hypothesis of bothremydid relationships in spite of the presence in Pelomedusoides of remarkably uniform shells"--P. 6-8

Taxonomic Composition and Trophic Structure of the Continental Bony Fish Assemblage from the Early Late Cretaceous of Southeastern Morocco

International audienceThe mid-Cretaceous vertebrate assemblage from south-eastern Morocco is one of the mostdiversified continental vertebrate assemblages of this time worldwide. The bony fish component(coelacanths, lungfishes and ray-finned fishes) is represented by relatively completespecimens and, mostly, by fragmentary elements scattered along 250 kilometres of outcrops.Here we revisit the bony fish assemblage by studying both isolated remains collectedduring several fieldtrips and more complete material kept in public collections. The assemblagecomprises several lungfish taxa, with the first mention of the occurrence of Arganodustiguidiensis, and possibly two mawsoniid coelacanths. A large bichir, cf. Bawitius, is recordedand corresponds to cranial elements initially referred to ‘Stromerichthys’ from coevaldeposits in Egypt. The ginglymodians were diversified with a large ‘Lepidotes’ plus twoobaichthyids and a gar. We confirm here that this gar belongs to a genus distinctive fromRecent gars, contrary to what was suggested recently. Teleosteans comprise a poorlyknown ichthyodectiform, a notopterid, a probable osteoglossomorph and a large tselfatiiform,whose cranial anatomy is detailed. The body size and trophic level for each taxon areestimated on the basis of comparison with extant closely related taxa. We plotted the averagebody size versus average trophic level for the Kem Kem assemblage, together with extantmarine and freshwater assemblages. The Kem Kem assemblage is characterized bytaxa of proportionally large body size, and by a higher average trophic level than the trophiclevel of the extant compared freshwater ecosystems, but lower than for the extant marineecosystems. These results should be regarded with caution because they rest on a reconstructedassemblage known mostly by fragmentary remains. They reinforce, however, theecological oddities already noticed for this mid-Cretaceous vertebrate ecosystem in NorthAfrica

Validation of a Dietary Questionnaire to Screen Omega-3 Fatty Acids Levels in Healthy Adults

To facilitate a clinical observational study to identify healthy volunteers with low (defined as ≤4%) and high (defined as ≥5.5%) omega-3 indices, a dietary questionnaire to rapidly assess habitual dietary intake of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) was developed. This study aimed to determine the validity of this newly developed dietary questionnaire. One hundred and eight volunteers were included and were assessed for habitual dietary intake of EPA and DHA using the questionnaire. The United States Department of Agriculture food products database and nutrition fact label was referenced for calculation. Blood samples were collected for the analysis of fatty acids in whole blood specimens and to derive omega-3 indices. A linear correlation was observed between reported dietary consumption of EPA, DHA, EPA+DHA and the whole blood levels of EPA, DHA, and the omega-3 indices ( = 0.67, 0.62, 0.67, respectively, \u3c 0.001 for all). The findings also suggested that the questionnaire was substantially better at identifying volunteers with high omega-3 indices (sensitivity 89%, specificity 84%, and agreement 86%) compared to volunteers with low omega-3 indices (sensitivity 100%, specificity 66%, and agreement 42%). In conclusion, this newly developed questionnaire is an efficient tool for the assessment of omega-3 indices in study populations and is particularly effective in identifying individuals with high omega-3 indices

TRPA1 mediates changes in heart rate variability and cardiac mechanical function in mice exposed to acrolein

Short-term exposure to ambient air pollution is linked with adverse cardiovascular effects. While previous research focused primarily on particulate matter-induced responses, gaseous air pollutants also contribute to cause short-term cardiovascular effects. Mechanisms underlying such effects have not been adequately described, however the immediate nature of the response suggests involvement of irritant neural activation and downstream autonomic dysfunction. Thus, this study examines the role of TRPA1, an irritant sensory receptor found in the airways, in the cardiac response of mice to acrolein and ozone. Conscious unrestrained wild-type C57BL/6 (WT) and TRPA1 knockout (KO) mice implanted with radiotelemeters were exposed once to 3 ppm acrolein, 0.3 ppm ozone, or filtered air. Heart rate (HR) and electrocardiogram (ECG) were recorded continuously before, during and after exposure. Analysis of ECG morphology, incidence of arrhythmia and heart rate variability (HRV) were performed. Cardiac mechanical function was assessed using a Langendorff perfusion preparation 24 h post-exposure. Acrolein exposure increased HRV independent of HR, as well as incidence of arrhythmia. Acrolein also increased left ventricular developed pressure in WT mice at 24 h post-exposure. Ozone did not produce any changes in cardiac function. Neither gas produced ECG effects, changes in HRV, arrhythmogenesis, or mechanical function in KO mice. These data demonstrate that a single exposure to acrolein causes cardiac dysfunction through TRPA1 activation and autonomic imbalance characterized by a shift toward parasympathetic modulation. Furthermore, it is clear from the lack of ozone effects that although gaseous irritants are capable of eliciting immediate cardiac changes, gas concentration and properties play important roles