ABSTRACT This project assesses intraspecific variation through the ontogeny of the ammonite Scaphites whitfieldi Cobban, 1951, from the Upper Cretaceous of the U.S. Western Interior. Our sample consists of 103 dorsoventral cross sections from nine localities that represent two lithofacies (shale and siltstone). We measured four shell parameters (ww/dm, ww/wh, uw/ dm, and WER) to describe the ontogenetic changes in shell morphology. We investigated the variation at three growth stages: immediately after hatching (dm = 1 mm), the neanoconch (dm = 4 mm), and the submature stage (defined as at or near the base of the mature hooklike body chamber). In general, the shell becomes more discoidal through ontogeny with a narrower umbilicus and a more compressed whorl section. The results of the univariate analysis indicate that the variation is statistically significantly higher in the neanoconch than in either the hatchling or submature stage. This pattern is also apparent in the multivariate analysis in which the disparity increases markedly from the hatchling to the neanoconch and then decreases again at the submature stage. These results are consistent with the hypothesis that the neanoconch represents a transition in the life history of the animal to a more demersal mode of life followed by a canalization of morphology toward maturity. However, because the neanic transition occurs over a range of sizes, it is possible that some individuals may have already undergone these changes at dm = 4 mm, whereas others may not have, thus inflating the degree of variation. To resolve this issue in the future, it is critical to examine each ontogenetic trajectory individually to pinpoint the exact size at which the morphological changes occur. We also compared the values of ww/dm, ww/wh, uw/dm, and WER of the three growth stages for the sample from siltstone versus the sample from shale. The comparison reveals that the specimens from siltstone occupy lower regions of the morphospace, implying that these specimens are generally more compressed than those from shale. This difference may be related to selection pressures for improved hydrodynamic efficiency in the higher energy environment represented by siltstone.
{"title":"Intraspecific Variation through Ontogeny in Late Cretaceous Ammonites","authors":"C. Klein, N. Landman","doi":"10.1206/3922.1","DOIUrl":"https://doi.org/10.1206/3922.1","url":null,"abstract":"ABSTRACT This project assesses intraspecific variation through the ontogeny of the ammonite Scaphites whitfieldi Cobban, 1951, from the Upper Cretaceous of the U.S. Western Interior. Our sample consists of 103 dorsoventral cross sections from nine localities that represent two lithofacies (shale and siltstone). We measured four shell parameters (ww/dm, ww/wh, uw/ dm, and WER) to describe the ontogenetic changes in shell morphology. We investigated the variation at three growth stages: immediately after hatching (dm = 1 mm), the neanoconch (dm = 4 mm), and the submature stage (defined as at or near the base of the mature hooklike body chamber). In general, the shell becomes more discoidal through ontogeny with a narrower umbilicus and a more compressed whorl section. The results of the univariate analysis indicate that the variation is statistically significantly higher in the neanoconch than in either the hatchling or submature stage. This pattern is also apparent in the multivariate analysis in which the disparity increases markedly from the hatchling to the neanoconch and then decreases again at the submature stage. These results are consistent with the hypothesis that the neanoconch represents a transition in the life history of the animal to a more demersal mode of life followed by a canalization of morphology toward maturity. However, because the neanic transition occurs over a range of sizes, it is possible that some individuals may have already undergone these changes at dm = 4 mm, whereas others may not have, thus inflating the degree of variation. To resolve this issue in the future, it is critical to examine each ontogenetic trajectory individually to pinpoint the exact size at which the morphological changes occur. We also compared the values of ww/dm, ww/wh, uw/dm, and WER of the three growth stages for the sample from siltstone versus the sample from shale. The comparison reveals that the specimens from siltstone occupy lower regions of the morphospace, implying that these specimens are generally more compressed than those from shale. This difference may be related to selection pressures for improved hydrodynamic efficiency in the higher energy environment represented by siltstone.","PeriodicalId":55527,"journal":{"name":"American Museum Novitates","volume":"2019 1","pages":"1 - 25"},"PeriodicalIF":1.5,"publicationDate":"2019-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42654743","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT Didelphis marsupialis, type species of the genus Didelphis, is a widely distributed and commonly studied American marsupial. Unfortunately, the previously noncontroversial application of the epithet marsupialis Linnaeus, 1758, has recently been called into question, and the lectotype is no longer extant. To preserve long-standing binomial usage for this species and other congeneric taxa, we designate a specimen from Surinam in the Royal Ontario Museum as neotype.
{"title":"A Neotype for Didelphis marsupialis Linnaeus, 1758","authors":"Â. Feijó, R. Voss","doi":"10.1206/3923.1","DOIUrl":"https://doi.org/10.1206/3923.1","url":null,"abstract":"ABSTRACT Didelphis marsupialis, type species of the genus Didelphis, is a widely distributed and commonly studied American marsupial. Unfortunately, the previously noncontroversial application of the epithet marsupialis Linnaeus, 1758, has recently been called into question, and the lectotype is no longer extant. To preserve long-standing binomial usage for this species and other congeneric taxa, we designate a specimen from Surinam in the Royal Ontario Museum as neotype.","PeriodicalId":55527,"journal":{"name":"American Museum Novitates","volume":" ","pages":"1 - 12"},"PeriodicalIF":1.5,"publicationDate":"2019-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48827178","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT The phylogenetic positions of Cretaceous species of Ceratopogonidae previously placed in the genera Archiculicoides Szadziewski, Protoculicoides Boesel, and Atriculicoides Remm are reappraised in light of synapomorphies. Character states are discussed in detail, supported by new photographs of Protoculicoides depressus Boesel, the description of Protoculicoides revelatus, n. sp., from Burmese amber, and a compilation of previously published illustrations. The recent article by Szadziewski et al. (2016) proposing that Protoculicoides and Atriculicoides are congeneric is shown to be inaccurate. At least three separate lineages are represented by species in these two genera, requiring a new genus, Gerontodacus (type species, G. succineus (Szadziewski)), to include some of them. Archiculicoides, Protoculicoides, Gerontodacus, Adelohelea Borkent and Alautunmyia Borkent remain undetermined to subfamily. As a result of phylogenetic and other taxonomic considerations, the following are new combinations: Gerontodacus krzeminskii (Choufani, Azar, and Nel), Gerontodacus punctus (Borkent), Gerontodacus skalskii (Szadziewski and Arillo), Archiaustroconops andersoni (Szadziewski, Ross, and Giłka), Atriculicoides ciliatus (Borkent), Atriculicoides hispanicus (Szadziewski and Arillo), Atriculicoides sanjusti (Szadziewski and Arillo) and Adelohelea burmitica (Szadziewski and Poinar). The following species are returned to the genera they were assigned to before Szadziewski et al. (2016): Atriculicoides cenomanensis Szadziewski and Schlüter, Atriculicoides dasyheleis Szadziewski, Atriculicoides globosus (Boesel), Atriculicoides incompletus Szadziewski and Schlüter, Atriculicoides macrophthalmus Remm, Atriculicoides sibiricus Szadziewski, Atriculicoides swinhoei (Cockerell), Atriculicoides szadziewskii Pérez-de la Fuente, Delclòs, Peñalver, and Arillo and Atriculicoides taimyricus Szadziewski. A key is provided to all Cretaceous Ceratopogonidae genera.
摘要对白垩纪蠓科原属Archiculicoides Szadziewski属、Protoculicoides Boesel属和atricicoides Remm属的蠓科物种的系统发育地位进行了重新评价。本文通过对Protoculicoides depressus Boesel的新照片、对缅甸琥珀中Protoculicoides revelatus, n. sp的描述以及先前发表的插图汇编，详细讨论了其特征状态。Szadziewski等人(2016)最近的一篇文章提出Protoculicoides和atricicoides是同源的，这被证明是不准确的。这两个属中的种至少代表了三个独立的谱系，需要一个新的属，Gerontodacus(模式种，G. succineus (Szadziewski))，以包括其中的一些。Archiculicoides, Protoculicoides, Gerontodacus, Adelohelea Borkent和Alautunmyia Borkent的亚科尚未确定。以下物种回归到Szadziewski et al.(2016)之前归属的属:萨曼蠓和schl、达西蠓、球形蠓、不完全蠓和schl、大眼蠓、西伯利亚蠓、斯文蠓、萨德兹耶夫斯基蠓、萨德兹耶夫斯基蠓、萨德兹耶夫斯基蠓、萨德兹耶夫斯基蠓、Delclòs、Peñalver以及萨德兹耶夫斯基蠓和泰米斯基蠓。提供了白垩纪所有蠓科属的钥匙。
{"title":"The Phylogenetic Relationships of Cretaceous Biting Midges, with a Key to All Known Genera (Diptera: Ceratopogonidae)","authors":"A. Borkent","doi":"10.1206/3921.1","DOIUrl":"https://doi.org/10.1206/3921.1","url":null,"abstract":"ABSTRACT The phylogenetic positions of Cretaceous species of Ceratopogonidae previously placed in the genera Archiculicoides Szadziewski, Protoculicoides Boesel, and Atriculicoides Remm are reappraised in light of synapomorphies. Character states are discussed in detail, supported by new photographs of Protoculicoides depressus Boesel, the description of Protoculicoides revelatus, n. sp., from Burmese amber, and a compilation of previously published illustrations. The recent article by Szadziewski et al. (2016) proposing that Protoculicoides and Atriculicoides are congeneric is shown to be inaccurate. At least three separate lineages are represented by species in these two genera, requiring a new genus, Gerontodacus (type species, G. succineus (Szadziewski)), to include some of them. Archiculicoides, Protoculicoides, Gerontodacus, Adelohelea Borkent and Alautunmyia Borkent remain undetermined to subfamily. As a result of phylogenetic and other taxonomic considerations, the following are new combinations: Gerontodacus krzeminskii (Choufani, Azar, and Nel), Gerontodacus punctus (Borkent), Gerontodacus skalskii (Szadziewski and Arillo), Archiaustroconops andersoni (Szadziewski, Ross, and Giłka), Atriculicoides ciliatus (Borkent), Atriculicoides hispanicus (Szadziewski and Arillo), Atriculicoides sanjusti (Szadziewski and Arillo) and Adelohelea burmitica (Szadziewski and Poinar). The following species are returned to the genera they were assigned to before Szadziewski et al. (2016): Atriculicoides cenomanensis Szadziewski and Schlüter, Atriculicoides dasyheleis Szadziewski, Atriculicoides globosus (Boesel), Atriculicoides incompletus Szadziewski and Schlüter, Atriculicoides macrophthalmus Remm, Atriculicoides sibiricus Szadziewski, Atriculicoides swinhoei (Cockerell), Atriculicoides szadziewskii Pérez-de la Fuente, Delclòs, Peñalver, and Arillo and Atriculicoides taimyricus Szadziewski. A key is provided to all Cretaceous Ceratopogonidae genera.","PeriodicalId":55527,"journal":{"name":"American Museum Novitates","volume":"2019 1","pages":"1 - 48"},"PeriodicalIF":1.5,"publicationDate":"2019-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45691522","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hollister W. Herhold, S. Davis, C. Smith, M. Engel, D. Grimaldi
ABSTRACT Bees of the family Halictidae (Apoidea: Anthophila) have three pairs of thick, bundled muscles that are circular to subcircular in cross section within the first metasomal segment, as revealed by micro-CT scanning of 16 species in 15 genera of five bee families. In nonhalictids and the basal halictid subfamily Rophitinae, these muscles are planar (flat and sheetlike), typically lying between the anterior air sacs and abdominal wall. In Nomiinae and Halictinae, these muscles, especially the dorsal-ventral pair, bulge into air-sac space, partly enveloped by air-sac membrane. A possible function may be to facilitate metasomal compression and contraction, and thus air flow. The bundled shape of these derived halictid muscles is similar to that of flight muscles, but further data is needed to determine if they are fibrillar, which would suggest a completely different function.
{"title":"Unique Metasomal Musculature in Sweat Bees (Hymenoptera: Apoidea: Halictidae) Revealed by Micro-CT Scanning","authors":"Hollister W. Herhold, S. Davis, C. Smith, M. Engel, D. Grimaldi","doi":"10.1206/3920.1","DOIUrl":"https://doi.org/10.1206/3920.1","url":null,"abstract":"ABSTRACT Bees of the family Halictidae (Apoidea: Anthophila) have three pairs of thick, bundled muscles that are circular to subcircular in cross section within the first metasomal segment, as revealed by micro-CT scanning of 16 species in 15 genera of five bee families. In nonhalictids and the basal halictid subfamily Rophitinae, these muscles are planar (flat and sheetlike), typically lying between the anterior air sacs and abdominal wall. In Nomiinae and Halictinae, these muscles, especially the dorsal-ventral pair, bulge into air-sac space, partly enveloped by air-sac membrane. A possible function may be to facilitate metasomal compression and contraction, and thus air flow. The bundled shape of these derived halictid muscles is similar to that of flight muscles, but further data is needed to determine if they are fibrillar, which would suggest a completely different function.","PeriodicalId":55527,"journal":{"name":"American Museum Novitates","volume":" ","pages":"1 - 28"},"PeriodicalIF":1.5,"publicationDate":"2019-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48543036","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. R. Carvalho, A. Giaretta, A. Angulo, C. Haddad, P. Peloso
ABSTRACT Leptodactylid frogs are phenotypically diverse, widely distributed across the Neotropics, and are known to harbor high levels of cryptic species diversity. This is especially true in Adenomera, where several candidate species have been recognized in a genetics-based study. Here we describe a new Amazonian species of Adenomera, which corresponds to one of the lineages previously identified as a candidate species (“sp. F”). Adenomera phonotriccus, n. sp., differs from all 18 recognized congeners by its unique advertisement call. Moreover, this species can be distinguished from nearly all congeners (except A. cotuba and A. lutzi) in having antebrachial tubercles on the undersides of its forearms. The distribution of A. phonotriccus seems to be restricted to the Araguaia- Xingu interfluve, in the eastern portion of the Brazilian state of Pará. Additional sampling effort on the right margin of the Araguaia River and along the Xingu River drainage should clarify the distribution of A. phonotriccus and perhaps result in the discovery of additional undescribed species of Adenomera in a region with high biological diversity.
细趾蛙具有表型多样性，广泛分布在新热带地区，并且具有高水平的隐物种多样性。在腺瘤中尤其如此，在一项基于遗传学的研究中，已经发现了几个候选物种。在这里，我们描述了一种新的亚马逊腺瘤虫，它对应于以前被确定为候选物种的一个谱系(“sp. F”)。腺瘤虫(Adenomera phonotriccus, n. sp)因其独特的广告叫声而不同于所有18种已知的同类。此外，这个物种可以与几乎所有的同族(除了A. cotuba和A. lutzi)区分开来，因为它的前臂下侧有前臂结节。沙锥蝽的分布似乎仅限于巴西帕尔州东部的阿拉瓜亚-新古交界地带。在阿拉瓜亚河右岸和新古河流域进行额外的采样工作，应该可以澄清a . phonotriccus的分布，并可能在生物多样性高的地区发现更多未描述的腺瘤虫物种。
{"title":"A New Amazonian Species of Adenomera (Anura: Leptodactylidae) from the Brazilian State of Pará: A Tody-Tyrant Voice in a Frog","authors":"T. R. Carvalho, A. Giaretta, A. Angulo, C. Haddad, P. Peloso","doi":"10.1206/3919.1","DOIUrl":"https://doi.org/10.1206/3919.1","url":null,"abstract":"ABSTRACT Leptodactylid frogs are phenotypically diverse, widely distributed across the Neotropics, and are known to harbor high levels of cryptic species diversity. This is especially true in Adenomera, where several candidate species have been recognized in a genetics-based study. Here we describe a new Amazonian species of Adenomera, which corresponds to one of the lineages previously identified as a candidate species (“sp. F”). Adenomera phonotriccus, n. sp., differs from all 18 recognized congeners by its unique advertisement call. Moreover, this species can be distinguished from nearly all congeners (except A. cotuba and A. lutzi) in having antebrachial tubercles on the undersides of its forearms. The distribution of A. phonotriccus seems to be restricted to the Araguaia- Xingu interfluve, in the eastern portion of the Brazilian state of Pará. Additional sampling effort on the right margin of the Araguaia River and along the Xingu River drainage should clarify the distribution of A. phonotriccus and perhaps result in the discovery of additional undescribed species of Adenomera in a region with high biological diversity.","PeriodicalId":55527,"journal":{"name":"American Museum Novitates","volume":"3919 1","pages":"1 - 21"},"PeriodicalIF":1.5,"publicationDate":"2019-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45184425","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Russell K. Engelman, J. J. Flynn, P. Gans, A. Wyss, D. Croft
ABSTRACT Sparassodont metatherians were the dominant terrestrial mammalian predators during South America's long Cenozoic isolation. This group's early fossil record is very poor, however, particularly for the late Eocene and early Oligocene. Here, we describe a new sparassodont, Chlorocyon phantasma, gen. et sp. nov., based on a specimen from Los Helados, a new locality within the Abanico Formation of the Andean Main Range of central Chile. New 40Ar/39Ar dates at Los Helados bracketing the fossil-bearing level constrain the age of this specimen to 37–36 Ma (late Eocene), indicating that this new taxon likely pertains to the Mustersan South American Land Mammal “Age.” Chlorocyon is the first Paleogene sparassodont reported from Chile and the first sparassodont described from the Abanico Formation. Distinctive features, including a p3 with an anterior edge that is more curved than the posterior edge and the lack of a hypoconulid on m4, suggest that Chlorocyon is a borhyaenoid closely related to Pharsophorus or Plesiofelis, although much smaller. Chlorocyon represents a welcome addition to the sparse record of late Eocene sparassodonts and indicates that the diversity of non-proborhyaenid borhyaenoids prior to the late Oligocene was greater than previously thought.
摘要:在南美洲漫长的新生代隔离时期，异齿兽是主要的陆生捕食动物。然而，该群的早期化石记录非常贫乏，尤其是始新世晚期和渐新世早期。在这里，我们描述了一种新的异齿兽，Chlorocyon phantasma, gen. et sp. nov.，基于来自智利中部安第斯山脉阿巴尼科组新地区Los Helados的标本。新的40Ar/39Ar年代在Los Helados的含化石水平将该标本的年龄限制在37 - 36ma(晚始新世)，表明该新分类群可能属于Mustersan南美陆地哺乳动物“时代”。Chlorocyon是在智利报道的第一种古近系异刺目，也是在Abanico组发现的第一种异刺目。其独特的特征，包括p3的前缘比后缘更弯曲，m4上没有下圆锥，表明Chlorocyon是一种与Pharsophorus或Plesiofelis密切相关的borhyaenoid，尽管小得多。Chlorocyon代表了对晚始新世稀疏的散齿兽记录的一个可喜的补充，它表明晚渐新世之前非原鸟目散齿兽的多样性比以前认为的要大。
{"title":"Chlorocyon phantasma, a Late Eocene Borhyaenoid (Mammalia: Metatheria: Sparassodonta) from the Los Helados Locality, Andean Main Range, Central Chile","authors":"Russell K. Engelman, J. J. Flynn, P. Gans, A. Wyss, D. Croft","doi":"10.1206/3918.1","DOIUrl":"https://doi.org/10.1206/3918.1","url":null,"abstract":"ABSTRACT Sparassodont metatherians were the dominant terrestrial mammalian predators during South America's long Cenozoic isolation. This group's early fossil record is very poor, however, particularly for the late Eocene and early Oligocene. Here, we describe a new sparassodont, Chlorocyon phantasma, gen. et sp. nov., based on a specimen from Los Helados, a new locality within the Abanico Formation of the Andean Main Range of central Chile. New 40Ar/39Ar dates at Los Helados bracketing the fossil-bearing level constrain the age of this specimen to 37–36 Ma (late Eocene), indicating that this new taxon likely pertains to the Mustersan South American Land Mammal “Age.” Chlorocyon is the first Paleogene sparassodont reported from Chile and the first sparassodont described from the Abanico Formation. Distinctive features, including a p3 with an anterior edge that is more curved than the posterior edge and the lack of a hypoconulid on m4, suggest that Chlorocyon is a borhyaenoid closely related to Pharsophorus or Plesiofelis, although much smaller. Chlorocyon represents a welcome addition to the sparse record of late Eocene sparassodonts and indicates that the diversity of non-proborhyaenid borhyaenoids prior to the late Oligocene was greater than previously thought.","PeriodicalId":55527,"journal":{"name":"American Museum Novitates","volume":"1 1","pages":"1 - 22"},"PeriodicalIF":1.5,"publicationDate":"2018-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1206/3918.1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46397999","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT A new species of smiliogastrin cyprinid is described from the Louesse, Lekoumou (upper Niari basin), and Djoulou (upper Ogowe basin) rivers in the Republic of Congo, west-central Africa. The new species is readily distinguished from congeners by the presence of a flexible, weakly ossified and smooth bordered last unbranched dorsal-fin ray, well-developed barbels, and a straight and complete lateral line in combination with a characteristic pigmentation patterning consisting of a distinctive, rounded black spot at the base of and extending over the first rays of the anal fin and a prominent, darkly pigmented blotch over the base of the anterior dorsal-fin rays. A combination of morphological features and pigmentation patterning that appears to be unique among Enteromius. The new species is widespread throughout the Louesse-Djoulou region, and the fact that such a seemingly common species has gone undetected until now serves to underscore how poorly known this region of the Republic of Congo remains.
{"title":"A New Small Barb (Cyprininae: Smiliogastrini) from the Louesse, Lekoumou (Upper Niari Basin), and Djoulou (Upper Ogowe Basin) Rivers in the Republic of Congo, West-Central Africa","authors":"V. Mamonekene, A. Zamba, M. Stiassny","doi":"10.1206/3917.1","DOIUrl":"https://doi.org/10.1206/3917.1","url":null,"abstract":"ABSTRACT A new species of smiliogastrin cyprinid is described from the Louesse, Lekoumou (upper Niari basin), and Djoulou (upper Ogowe basin) rivers in the Republic of Congo, west-central Africa. The new species is readily distinguished from congeners by the presence of a flexible, weakly ossified and smooth bordered last unbranched dorsal-fin ray, well-developed barbels, and a straight and complete lateral line in combination with a characteristic pigmentation patterning consisting of a distinctive, rounded black spot at the base of and extending over the first rays of the anal fin and a prominent, darkly pigmented blotch over the base of the anterior dorsal-fin rays. A combination of morphological features and pigmentation patterning that appears to be unique among Enteromius. The new species is widespread throughout the Louesse-Djoulou region, and the fact that such a seemingly common species has gone undetected until now serves to underscore how poorly known this region of the Republic of Congo remains.","PeriodicalId":55527,"journal":{"name":"American Museum Novitates","volume":"1 1","pages":"1 - 16"},"PeriodicalIF":1.5,"publicationDate":"2018-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42341597","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
G. Morgan, Nancy A. Albury, R. Rímoli, Phillip Lehman, A. Rosenberger, S. Cooke
ABSTRACT Late Quaternary fossils representing a locally extinct population of the Cuban crocodile (Crocodylus rhombifer) are reported from two underwater caves in the Dominican Republic. A large fossil sample of C. rhombifer, from Oleg's Bat Cave near Bavaro in the southeastern Dominican Republic, consists of four nearly complete skulls, numerous isolated cranial elements and mandibles, and more than 100 postcranial bones representing most of the skeleton. These fossils were collected from a completely submerged portion of the cave at a depth of 11 m and about 100 m from the nearest entrance. A skull, mandibles, and two vertebrae of a Cuban crocodile were also found in a second cave called Ni-Rahu, northeast of Santo Domingo. We identify the fossil crocodile skulls from the Dominican Republic as Crocodylus rhombifer because they share the following characters with modern skulls of C. rhombifer from Cuba (as well as fossil skulls from Cuba, the Bahamas, and Cayman Islands): short, broad, and deep rostrum; large orbits; convex nasals along the midline (midrostral boss); prominent swelling on the lacrimals anterior and medial to the orbits; low but obvious ridges extending anteriorly from the lacrimals to the nasals and posteriorly from the lacrimals to the prefrontals and frontals, outlining a distinct diamond- or rhomboid-shaped structure; strongly concave interorbital region and cranial roof; high, narrow ridges on the internal margins of the orbits, extending from the prefrontals to the frontals and posteriorly to the postorbitals; prominent ridges along the lateral margins of the cranial roof on the postorbitals and squamosals, terminating as noticeable protuberances on the posterolateral corners of the squamosals; premaxillary/maxillary suture on the palate essentially horizontal or transverse to the long axis of the skull at the level of the first maxillary tooth; 13 teeth in the maxilla. Certain aspects of the ecology and anatomy of living Crocodylus rhombifer in Cuba, and carbon isotope data from fossil crocodile bones from both the Dominican Republic and the Bahamas, indicate that the Cuban crocodile is a terrestrially adapted predator. The fossil deposits in Oleg's Bat Cave and other underwater caves in the Dominican Republic lack freshwater vertebrates, such as fish and turtles, but contain abundant samples of hystricognath rodents, small ground sloths, and other terrestrial vertebrates, including large land tortoises, that apparently were the primary prey of the crocodiles. Bats are abundant in the fossil deposits in Oleg's Bat Cave, and may have been an additional food source. Bone collagen from a tibia of C. rhombifer from Oleg's Bat Cave yielded an AMS radiocarbon date of 6460 ±30 ryrBP (equivalent to 7320 to 7430 cal yrBP). The chronology for the local extinction of C. rhombifer in Hispaniola is currently unknown, except to document the presence of this species in the eastern Dominican Republic in the early Holocene. Radiocarbon dat
{"title":"The Cuban Crocodile (Crocodylus rhombifer) from Late Quaternary Underwater Cave Deposits in the Dominican Republic","authors":"G. Morgan, Nancy A. Albury, R. Rímoli, Phillip Lehman, A. Rosenberger, S. Cooke","doi":"10.1206/3916.1","DOIUrl":"https://doi.org/10.1206/3916.1","url":null,"abstract":"ABSTRACT Late Quaternary fossils representing a locally extinct population of the Cuban crocodile (Crocodylus rhombifer) are reported from two underwater caves in the Dominican Republic. A large fossil sample of C. rhombifer, from Oleg's Bat Cave near Bavaro in the southeastern Dominican Republic, consists of four nearly complete skulls, numerous isolated cranial elements and mandibles, and more than 100 postcranial bones representing most of the skeleton. These fossils were collected from a completely submerged portion of the cave at a depth of 11 m and about 100 m from the nearest entrance. A skull, mandibles, and two vertebrae of a Cuban crocodile were also found in a second cave called Ni-Rahu, northeast of Santo Domingo. We identify the fossil crocodile skulls from the Dominican Republic as Crocodylus rhombifer because they share the following characters with modern skulls of C. rhombifer from Cuba (as well as fossil skulls from Cuba, the Bahamas, and Cayman Islands): short, broad, and deep rostrum; large orbits; convex nasals along the midline (midrostral boss); prominent swelling on the lacrimals anterior and medial to the orbits; low but obvious ridges extending anteriorly from the lacrimals to the nasals and posteriorly from the lacrimals to the prefrontals and frontals, outlining a distinct diamond- or rhomboid-shaped structure; strongly concave interorbital region and cranial roof; high, narrow ridges on the internal margins of the orbits, extending from the prefrontals to the frontals and posteriorly to the postorbitals; prominent ridges along the lateral margins of the cranial roof on the postorbitals and squamosals, terminating as noticeable protuberances on the posterolateral corners of the squamosals; premaxillary/maxillary suture on the palate essentially horizontal or transverse to the long axis of the skull at the level of the first maxillary tooth; 13 teeth in the maxilla. Certain aspects of the ecology and anatomy of living Crocodylus rhombifer in Cuba, and carbon isotope data from fossil crocodile bones from both the Dominican Republic and the Bahamas, indicate that the Cuban crocodile is a terrestrially adapted predator. The fossil deposits in Oleg's Bat Cave and other underwater caves in the Dominican Republic lack freshwater vertebrates, such as fish and turtles, but contain abundant samples of hystricognath rodents, small ground sloths, and other terrestrial vertebrates, including large land tortoises, that apparently were the primary prey of the crocodiles. Bats are abundant in the fossil deposits in Oleg's Bat Cave, and may have been an additional food source. Bone collagen from a tibia of C. rhombifer from Oleg's Bat Cave yielded an AMS radiocarbon date of 6460 ±30 ryrBP (equivalent to 7320 to 7430 cal yrBP). The chronology for the local extinction of C. rhombifer in Hispaniola is currently unknown, except to document the presence of this species in the eastern Dominican Republic in the early Holocene. Radiocarbon dat","PeriodicalId":55527,"journal":{"name":"American Museum Novitates","volume":"1 1","pages":"1 - 56"},"PeriodicalIF":1.5,"publicationDate":"2018-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1206/3916.1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43696817","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. Amorim, S. S. Oliveira, Andrea C. Henao-sepúlveda
ABSTRACT Eumanota wolffae, sp. nov., is described from the high Andean forests of Colombia. This is the first Neotropical species of the clade of non-Manota genera of the mycetophilid subfamily Manotinae—to date known entirely from the Oriental and the northwestern Australasian regions, and in Baltic amber. With the other species of Eumanota Edwards, this species shares, among other features, a largely developed third maxillary palpomere, projecting beyond the base of fourth palpomere, with a wide sensorial pit, a flat inner face, and the last palpomere at least 4× the length of the fourth palpomere. The systematic position of the Colombian species within the Manotinae is addressed. The biogeographic significance of Eumanota in the Neotropical region is discussed, interpreted here as a concurrent incidence of a circumtropical pattern and Gondwanan distributions, in other words, a particular pattern of biogeographic pseudocongruence, referred to here as a “pseudogondwanan pattern.” This pattern is associated with an early Cenozoic tropical biota over Laurasian terranes that expanded its distribution to the south (in the Americas, Africa, and Australasia), followed by large-scale extinction of Nearctic and Palearctic representatives due to global cooling in the Neogene. A discussion is provided about the correlation between these patterns and evidence of Late Cretaceous-Paleogene tropical floras over Laurasian terranes.
{"title":"A New Species of Eumanota Edwards (Diptera: Mycetophilidae: Manotine) from Colombia: Evidence for a Pseudogondwanan Pattern","authors":"D. Amorim, S. S. Oliveira, Andrea C. Henao-sepúlveda","doi":"10.1206/3915.1","DOIUrl":"https://doi.org/10.1206/3915.1","url":null,"abstract":"ABSTRACT Eumanota wolffae, sp. nov., is described from the high Andean forests of Colombia. This is the first Neotropical species of the clade of non-Manota genera of the mycetophilid subfamily Manotinae—to date known entirely from the Oriental and the northwestern Australasian regions, and in Baltic amber. With the other species of Eumanota Edwards, this species shares, among other features, a largely developed third maxillary palpomere, projecting beyond the base of fourth palpomere, with a wide sensorial pit, a flat inner face, and the last palpomere at least 4× the length of the fourth palpomere. The systematic position of the Colombian species within the Manotinae is addressed. The biogeographic significance of Eumanota in the Neotropical region is discussed, interpreted here as a concurrent incidence of a circumtropical pattern and Gondwanan distributions, in other words, a particular pattern of biogeographic pseudocongruence, referred to here as a “pseudogondwanan pattern.” This pattern is associated with an early Cenozoic tropical biota over Laurasian terranes that expanded its distribution to the south (in the Americas, Africa, and Australasia), followed by large-scale extinction of Nearctic and Palearctic representatives due to global cooling in the Neogene. A discussion is provided about the correlation between these patterns and evidence of Late Cretaceous-Paleogene tropical floras over Laurasian terranes.","PeriodicalId":55527,"journal":{"name":"American Museum Novitates","volume":"2018 1","pages":"1 - 19"},"PeriodicalIF":1.5,"publicationDate":"2018-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47647306","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
B. Bai, Yuanqing Wang, Qian Li, Haibing Wang, Fangyuan Mao, Yan-Xin Gong, Jin Meng
ABSTRACT Extant perissodactyls (horses, rhinos, and tapirs) comprise a small portion of living mammals, but fossil perissodactyls were more diverse and commonly dominated Paleogene faunas. Unfortunately, the taxonomy and distribution of some Chinese Paleogene perissodactyls remain controversial and unclear, hampering the correlation of Asian paleofaunas with paleofaunas from other continents. Here we clarify the temporal and spatial distribution of Paleogene perissodactyl species from the Erlian Basin based on published specimens, archives, and our recent fieldwork. The strata of the Erlian Basin range nearly continuously from the late Paleocene to the early Oligocene, and almost all Eocene Asian Land Mammal Ages (ALMA) are based on corresponding faunas from the Erlian Basin. We revise the most complete section of deposits at Erden Obo (= Urtyn Obo) that range in age from the late Paleocene to the early Oligocene in the Erlian Basin, and correlate it with other type formations/faunas in the basin based mainly on the perissodactyl biostratigraphy and lithostratigraphy. Furthermore, we discuss perissodactyl faunal components and their diversity from the early Eocene to the early Oligocene in the Erlian Basin, as well as the correlation between middle Eocene ALMAs and North American Land Mammal Ages based on perissodactyl fossils. The general decrease in perissodactyl diversity from the middle Eocene to the late Eocene can probably be attributed to a global climatic cooling trend and related environmental changes. The diversity of perissodactyls declined distinctly during the Eocene-Oligocene Transition, when global average temperatures dropped considerably.
{"title":"Biostratigraphy and Diversity of Paleogene Perissodactyls from the Erlian Basin of Inner Mongolia, China","authors":"B. Bai, Yuanqing Wang, Qian Li, Haibing Wang, Fangyuan Mao, Yan-Xin Gong, Jin Meng","doi":"10.1206/3914.1","DOIUrl":"https://doi.org/10.1206/3914.1","url":null,"abstract":"ABSTRACT Extant perissodactyls (horses, rhinos, and tapirs) comprise a small portion of living mammals, but fossil perissodactyls were more diverse and commonly dominated Paleogene faunas. Unfortunately, the taxonomy and distribution of some Chinese Paleogene perissodactyls remain controversial and unclear, hampering the correlation of Asian paleofaunas with paleofaunas from other continents. Here we clarify the temporal and spatial distribution of Paleogene perissodactyl species from the Erlian Basin based on published specimens, archives, and our recent fieldwork. The strata of the Erlian Basin range nearly continuously from the late Paleocene to the early Oligocene, and almost all Eocene Asian Land Mammal Ages (ALMA) are based on corresponding faunas from the Erlian Basin. We revise the most complete section of deposits at Erden Obo (= Urtyn Obo) that range in age from the late Paleocene to the early Oligocene in the Erlian Basin, and correlate it with other type formations/faunas in the basin based mainly on the perissodactyl biostratigraphy and lithostratigraphy. Furthermore, we discuss perissodactyl faunal components and their diversity from the early Eocene to the early Oligocene in the Erlian Basin, as well as the correlation between middle Eocene ALMAs and North American Land Mammal Ages based on perissodactyl fossils. The general decrease in perissodactyl diversity from the middle Eocene to the late Eocene can probably be attributed to a global climatic cooling trend and related environmental changes. The diversity of perissodactyls declined distinctly during the Eocene-Oligocene Transition, when global average temperatures dropped considerably.","PeriodicalId":55527,"journal":{"name":"American Museum Novitates","volume":"1 1","pages":"1 - 60"},"PeriodicalIF":1.5,"publicationDate":"2018-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1206/3914.1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42333898","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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