Candidate cases of poecilogony in Neogastropoda: implications for the systematics of the genus Raphitoma Bellardi, 1847

2020 ◽  
Author(s):  
Valeria Russini ◽  
Riccardo Giannuzzi-Savelli ◽  
Francesco Pusateri ◽  
Jakov Prkic ◽  
Giulia Fassio ◽  
...  
Keyword(s):  
Larval Development ◽  
Intraspecific Variation ◽  
Sibling Species ◽  
Marine Invertebrates ◽  
Ancestral State ◽  
Reciprocal Monophyly ◽  
Evolutionary Transitions ◽  
North East ◽  
The North ◽  
Evolutionary Aspects

Poecilogony is the intraspecific variation in developmental mode, with larvae of different types produced by the same individual, population or species. It is very rare among marine invertebrates, and in gastropods has long been described only in a few opisthobranchs. The physiological and regulatory mechanisms underlying larval evolutionary transitions, such as loss of planktotrophy that occurred repeatedly in many caenogastropod lineages, are still largely unknown. We have studied the inter- v. intraspecific variation in larval development in the north-east Atlantic neogastropod genus Raphitoma Bellardi, 1847, starting with an iterative taxonomy approach: 17 morphology-based Preliminary Species Hypotheses were tested against a COI molecular-distance-based method (ABGD), and the retained species hypotheses were eventually inspected for reciprocal monophyly on a multilocus dataset. We subsequently performed an ancestral state reconstruction on an ultrametric tree of the 10 Final Species Hypotheses, time-calibrated by fossils, revealing that the interspecific changes were planktotrophy > lecithotrophy, and all have occurred in the Pleistocene, after 2.5 million years ago. This is suggestive of a major role played by Pleistocene Mediterranean oceanographic conditions – enhanced oligotrophy, unpredictable availability of water column resources – likely to favour loss of planktotrophy. Within this group of species, which has diversified after the Miocene, we identified one pair of sibling species differing in their larval development, Raphitoma cordieri (Payraudeau, 1826) and R. horrida (Monterosato, 1884). However, we also identified two Final Species Hypotheses, each comprising individuals with both larval developmental types. Our working hypothesis is that they correspond to one or two poecilogonous species. If confirmed by other nuclear markers, this would be the first documentation of poecilogony in the Neogastropoda, and the second in the whole Caenogastropoda. Although sibling species with different developmental strategies may offer good models to study some evolutionary aspects, poecilogonous taxa are optimally suited for identifying regulatory and developmental mechanisms underlying evolutionary transitions.

Systematics of the spider genus Neoleptoneta Brignoli, 1972 (Araneae:Leptonetidae) with a discussion of the morphology and relationships for the North American Leptonetidae

2011 ◽  
Vol 25 (4) ◽  
pp. 334 ◽  
Author(s):  
Joel Ledford ◽  
Pierre Paquin ◽  
James Cokendolpher ◽  
Josh Campbell ◽  
Charles Griswold
Keyword(s):  
North American ◽  
Sister Group ◽  
Morphological Data ◽  
New Combination ◽  
Sister Group Relationship ◽  
Ancestral State ◽  
New Combinations ◽  
Molecular Sequence ◽  
North East ◽  
The North

A phylogenetic analysis of the spider genus Neoleptoneta Brignoli, 1972 is presented based on molecular sequence variation from three genes (mitochondrial cytochrome c oxidase subunit I, nuclear histone H3 and nuclear 28S rDNA) and including exemplars for all North American leptonetid genera except the ecribellate archoleptonetine Darkoneta. Analysis of concatenated data and independent genes using Bayesian, maximum likelihood and parsimony methods failed to recover Neoleptoneta as monophyletic. The genera Archoleptoneta, Appaleptoneta and Calileptoneta are monophyletic and a sister group relationship is supported between Appaleptoneta and Calileptoneta. Morphological data based on a survey of leptonetid genera using scanning electron and compound light microscopy are discussed and traced on the molecular phylogeny. Images for each North American leptonetine genus are provided, including comparison with Asian and European outgroups. Images of the incertae sedis species Leptoneta brunnea Gertsch, 1974 and Leptoneta sandra Gertsch, 1974 are provided and their generic placement is re-evaluated. Ancestral state reconstruction is used to assess patterns of cave evolution and shows that most species are descended from troglophilic ancestors and that troglobites have evolved at least nine times independently within the North American Leptonetidae. Neoleptoneta is relimited to include seven species restricted to central Mexico including N. bonita (Gertsch, 1974), N. capilla (Gertsch, 1971), N. delicata (Gertsch, 1971), N. limpida (Gertsch, 1974), N. rainesi (Gertsch, 1971) and N. reclusa (Gertsch, 1971) and to include Leptoneta brunnea, giving the new combination N. brunnea (Gertsch, 1974). The remaining species described in Neoleptoneta are placed in three new genera: (1) Chisoneta, gen. nov. from south-western Texas and Nuevo Leon, Mexico, including the four species C. chisosea (Gertsch, 1974), C. isolata (Gertsch, 1971), C. modica (Gertsch, 1974) and C. pecki (Gertsch, 1971), new combinations; (2) Ozarkia, gen. nov. from Arizona and New Mexico north-east to Arkansas, Alabama and Georgia, including the nine species O. alabama (Gertsch, 1974), O. apachea (Gertsch, 1974), O. archeri (Gertsch, 1974), O. arkansa (Gertsch, 1974), O. blanda (Gertsch, 1974), O. georgia (Gertsch, 1974), O. ivei (Gertsch, 1974), O. novaegalleciae (Brignoli, 1979) and O. serena (Gertsch, 1974), new combinations; and (3) Tayshaneta, gen. nov. from Texas south to Coahuila, Mexico, with the eleven species T. anopica (Gertsch, 1974), T. bullis (Cokendolpher, 2004), T. coeca (Chamberlin & Ivie, 1942), T. concinna (Gertsch, 1974), T. devia (Gertsch, 1974), T. furtiva (Gertsch, 1974), T. microps (Gertsch, 1974), T. myopica (Gertsch, 1974), T. paraconcinna (Cokendolpher & Reddell, 2001), T. uvaldea (Gertsch, 1974) and T. valverdae (Gertsch, 1974), new combinations. Leptoneta sandra Gertsch, 1974 cannot be placed in any North American, European or Asian genus and is thus transferred to the new genus Montanineta, gen. nov., giving the new combination Montanineta sandra (Gertsch, 1974).

Demosponge fauna of Ormonde and Gettysburg Seamounts (Gorringe Bank, north-east Atlantic): diversity and zoogeographical affinities

2007 ◽  
Vol 87 (6) ◽  
pp. 1643-1653 ◽  
Author(s):  
Joana Xavier ◽  
Rob van Soest
Keyword(s):  
Shallow Water ◽  
Geographical Distribution ◽  
Marine Biota ◽  
East Atlantic ◽  
North East ◽  
The North ◽  
Gorringe Bank ◽  
High Level ◽  
Evolutionary Aspects

Seamounts, although abundant features of the world's oceans, constitute one of the least studied marine ecosystems. In the present work we assessed the diversity and zoogeographical affinities of the demosponge assemblages of Gettysburg and Ormonde Seamounts (Gorringe Bank, north-east Atlantic). Twenty-three demosponge species were identified adding to the thirteen previously reported for Gorringe shallow-water. Gorringe's demosponge assemblage was found to be mainly composed of species with a wide Atlanto–Mediterranean distribution (61%) and a group of species (28%) that are endemic to this Bank or have a restricted geographical distribution. This high level of endemism suggests the Gorringe Bank as a hotspot for demosponge fauna in the north-east Atlantic. Gorringe demosponge fauna was found to present an overall moderate similarity to the Mediterranean, Iberian coasts and Macaronesian archipelagos. We compare our findings with patterns reported for fish and molluscan faunas for this Bank and discuss some evolutionary aspects on the role of these ecosystems for the north-east Atlantic marine biota.

scholarly journals Challenges in building barcode reference libraries for marine invertebrates exemplified by the genus Prionospio (Annelida: Spionidae)

2021 ◽  
Vol 4 ◽  
Author(s):  
Martin Hektoen ◽  
Torbjørn Ekrem ◽  
Torkild Bakken
Keyword(s):  
Sanger Sequencing ◽  
Marine Invertebrates ◽  
Limiting Factor ◽  
Success Rates ◽  
Molecular Tools ◽  
Bioindicator Species ◽  
North East ◽  
The North ◽  
Amplification Rate ◽  
Substantial Bias

The completeness of reference libraries is often a limiting factor in the effectiveness of biomonitoring using molecular tools. The fact that these libraries are often built upon Sanger sequencing can create a substantial bias due to poor primer fits and unoptimized lab protocols. Some taxa of marine macroinvertebrates are known to be notoriously difficult to sequence using traditional, PCR-based means, and only about 15% of the known bioindicator species world-wide have publicly available sequences for any genetic marker (Aylagas et al. 2014). The Barcode of Life Data System (BOLD) indicates an amplification rate between 46% and 85% of the barcode region of COI for the most commonly used marine invertebrates that indicate pollution in the North East Atlantic (Capitellidae, Cirratulidae, Dorvilleidae, Spionidae and Tubificidae within Annelida, and Thyasiridae within Mollusca). A currently on-going integrative taxonomic study on Prionospio Malmgren, 1867 (Spionidae, Annelida) exemplifies the extensive issues of utilizing Sanger sequencing on marine invertebrates. The barcode region of COI was attempted amplified using five primer pairs: three designed to be universal for marine invertebrates (Folmer et al. 1994, Geller et al. 2013, Lobo et al. 2013), one specialized on polychaetes (Carr et al. 2011) and one self-designed. In addition, two DNA polymerases were tested (TaKaRa Ex Taq HS and Qiagen HotStarTaq) and three annealing temperatures. Only five sequences of COI were obtained from a total of 255 PCR reactions (2% success rate). Other genetic markers showed better amplification rates: 58% for 16S rDNA, and more than 90% success rates for 28S rDNA and Histone H3. This illustrates the importance of having more than one marker in mind when seeking to complete reference libraries, and the potential effectiveness of a multi-marker approach in molecular biomonitoring surveys. As sequencing costs decrease, utilizing shallow shotgun-based sequencing (genome skimming) on problematic groups such as Prionospio to bypass issues regarding unfit primers is also becoming a viable option.

Redescription and postmarsupial development of Apseudopsis latreillii (Crustacea: Tanaidacea)

2012 ◽  
Vol 92 (5) ◽  
pp. 1023-1041 ◽  
Author(s):  
P. Esquete ◽  
R.N. Bamber ◽  
J. Moreira ◽  
J.S. Troncoso
Keyword(s):  
Developmental Stage ◽  
Intraspecific Variation ◽  
Developmental Stages ◽  
East Atlantic ◽  
Diagnostic Characters ◽  
North East ◽  
The North ◽  
Preparatory Stage ◽  
Juvenile Stages ◽  
Pass Through

Apseudopsis latreillii is a common tanaidacean species widely-distributed in the north-east Atlantic, but its diagnostic characters remain unspecified. Furthermore, intraspecific variation in relation to its developmental stages has not been described. Knowledge about this variation is needed owing to the difficulty of identification of the significant number of juvenile specimens within samples, particularly when sympatric with other apseudid species. Specimens from three different localities of the north-east Atlantic have been examined, and the size of 766 individuals has been measured. Study of postmarsupial development shows that the manca II is followed by two juvenile stages before reaching maturity. Males present two possible morphologies. After a preparatory stage, females pass through a sequence of copulatory instars followed by intermediate stages in which the female loses the ovisac after manca release. Characters allowing the distinction of A. latreillii specimens regardless of developmental stage are the combination of a pointed and downturned rostrum, pereonites without apophyses, three ventral spines on the pereopod 1 propodus, and one dorsodistal spine on the merus.

Ras al Khaimah: further archaeological discoveries

Antiquity ◽  
1976 ◽  
Vol 50 (200) ◽  
pp. 216-222
Author(s):  
Beatrice De Cardi
Keyword(s):  
United Arab Emirates ◽  
The State ◽  
Focused Attention ◽  
North East ◽  
The North ◽  
History Of ◽  
The City

Ras a1 Khaimah is the most northerly of the seven states comprising the United Arab Emirates and its Ruler, H. H. Sheikh Saqr bin Mohammad al-Qasimi, is keenly interested in the history of the state and its people. Survey carried out there jointly with Dr D. B. Doe in 1968 had focused attention on the site of JuIfar which lies just north of the present town of Ras a1 Khaimah (de Cardi, 1971, 230-2). Julfar was in existence in Abbasid times and its importance as an entrep6t during the sixteenth and seventeenth centuries-the Portuguese Period-is reflected by the quantity and variety of imported wares to be found among the ruins of the city. Most of the sites discovered during the survey dated from that period but a group of cairns near Ghalilah and some long gabled graves in the Shimal area to the north-east of the date-groves behind Ras a1 Khaimah (map, FIG. I) clearly represented a more distant past.

Lichens in the North-East regions of Cyprus

1999 ◽  
Vol 110 (5-6) ◽  
pp. 455-463 ◽  
Author(s):  
S. Güvenç ◽  
Ş Öztürk
Keyword(s):  
North East ◽  
The North

TBE in Italy

2019 ◽  
Author(s):  
Valentina Tagliapietra ◽  
Flavia Riccardo ◽  
Giovanni Rezza
Keyword(s):  
Case Series ◽  
East Part ◽  
Mountainous Regions ◽  
North East ◽  
The North ◽  
Tick Borne Encephalitis ◽  
Low Incidence

Italy is considered a low incidence country for tick-borne encephalitis (TBE) in Europe. Areas at higher risk for TBE in Italy are geographically clustered in the forested and mountainous regions and provinces in the north east part of the country, as suggested by TBE case series published over the last decade.

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