Batillipes pennaki Marcus, 1946 (Arthrotardigrada: Batillipedidae): deciphering a species complex

Batillipes pennaki has been considered a common and a cosmopolitan marine tardigrade species. However, the original diagnosis of this species is very incomplete, and consequently there is a high probability of incorrect records. Therefore, a comparative analysis of quantitative and qualitative morphological characters among eight different populations from the Atlantic basin was done in this study to investigate if B. pennaki is a complex of similar species, each with a restricted distribution range. The result of discriminant analyses showed clear morphometric differences between populations that were arranged into three main groups, distinguishing Western Atlantic populations, Eastern Atlantic populations and a Mediterranean population. Furthermore, the result of analyses of morphological structures revealed peculiarities of some traits with taxonomic relevance, such as leg IV sensory organs and primary clavae, consistent with the clusters revealed by quantitative data, allowing us to distinguish three different pseudocryptic species and supporting the hypothesis that B. pennaki is a species complex.

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Identification of sibling species in the genus Eucyclops from water-bodies of Ukraine and Russia using crossbreeding studies

Ecology and Noospherology ◽

10.15421/031406 ◽

2014 ◽

Vol 25 (1-2) ◽

pp. 61-68 ◽

Cited By ~ 1

Author(s):

V. I. Monchenko ◽

L. P. Gaponova ◽

V. R. Alekseev

Keyword(s):

Cryptic Species ◽

River Basin ◽

Black Sea ◽

Species Complex ◽

River Basins ◽

Water Bodies ◽

Similar Species ◽

Basin Water ◽

Different Populations ◽

Baltic Sea Basin

Crossbreeding experiments were used to estimate cryptic species in water bodies of Ukraine and Russia because the most useful criterion in species independence is reproductive isolation. The problem of cryptic species in the genus Eucyclops was examined using interpopulation crosses of populations collected from Baltic Sea basin (pond of Strelka river basin) and Black Sea basin (water-reservoires of Dnieper, Dniester and Danube rivers basins). The results of reciprocal crosses in Eucyclops serrulatus-group are shown that E. serrulatus from different populations but from water bodies belonging to the same river basin crossed each others successfully. The interpopulation crosses of E. serrulatus populations collected from different river basins (Dnipro, Danube and Dniester river basins) were sterile. In this group of experiments we assigned evidence of sterility to four categories: 1) incomplete copulation or absence of copulation; 2) nonviable eggs; 3) absence of egg membranes or egg sacs 4) empty egg membranes. These crossbreeding studies suggest the presence of cryptic species in the E. serrulatus inhabiting ecologically different populations in many parts of its range. The same crossbreeding experiments were carries out between Eucyclops serrulatus and morphological similar species – Eucyclops macruroides from Baltic and Black Sea basins. The reciprocal crossings between these two species were sterile. Thus taxonomic heterogeneity among species of genus Eucyclops lower in E. macruroides than in E. serrulatus. The interpopulation crosses of E. macruroides populations collected from distant part of range were fertile. These crossbreeding studies suggest that E. macruroides species complex was evaluated as more stable than E. serrulatus species complex.

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Taxonomic notes on Alpheus inopinatus Holthuis & Gottlieb, 1958 and Alpheus cf. lobidens De Haan, 1849 from Kuwait (Malacostraca: Decapoda: Alpheidae)

Zootaxa ◽

10.11646/zootaxa.4851.1.10 ◽

2020 ◽

Vol 4851 (1) ◽

pp. 189-197

Author(s):

ARTHUR ANKER ◽

MANAL AL-KANDARI ◽

SAMMY DE GRAVE

Keyword(s):

Species Complex ◽

Morphological Characters ◽

Colour Pattern ◽

Similar Species ◽

Snapping Shrimp ◽

The Status ◽

The Common

The status of the common intertidal snapping shrimp, Alpheus inopinatus Holthuis & Gottlieb, 1958, is discussed based on newly collected material from Kuwait. Alpheus inopinatus was previously confused with morphologically very similar species in the Alpheus lobidens De Haan, 1849 species complex, formerly identified as A. crassimanus Heller, 1862 and herein tentatively referred to as A. cf. lobidens. The material herein examined strongly supports the validity of A. inopinatus based on several morphological characters, as well as differences in the colour pattern, compared to other members of the A. lobidens complex.

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Molecular phylogenetic analysis of the Paguristes tortugae Schmitt, 1933 complex and selected other Paguroidea (Crustacea: Decapoda: Anomura)

Zootaxa ◽

10.11646/zootaxa.4999.4.1 ◽

2021 ◽

Vol 4999 (4) ◽

pp. 301-324

Author(s):

CATHERINE W. CRAIG ◽

DARRYL L. FELDER

Keyword(s):

Phylogenetic Analysis ◽

Species Complex ◽

Morphological Characters ◽

Undescribed Species ◽

Mtdna Sequences ◽

Approximately Unbiased ◽

Western Atlantic ◽

Family Level ◽

Molecular Phylogenetic ◽

Similarities And Differences

Morphological characters, as presently applied to describe members of the Paguristes tortugae Schmitt, 1933 species complex, appear to be of limited value in inferring phylogenetic relationships within the genus, and may have similarly misinformed understanding of relationships between members of this complex and those presently assigned to the related genera Areopaguristes Rahayu & McLaughlin, 2010 and Pseudopaguristes McLaughlin, 2002. Previously undocumented observations of similarities and differences in color patterns among populations additionally suggest genetic divergences within some species, or alternatively seem to support phylogenetic groupings of some species. In the present study, a Maximum Likelihood (ML) phylogenetic analysis was undertaken based on the H3, 12S mtDNA, and 16S mtDNA sequences of 148 individuals, primarily representatives of paguroid species from the western Atlantic. This molecular analysis supported a polyphyletic Diogenidae Ortmann, 1892, although incomplete taxonomic sampling among the genera of Diogenidae limits the utility of this finding for resolving family level relationships. Several hypotheses regarding the evolutionary relationships among hermit crab genera were refuted by the Kishino-Hasegawa (KH). Shimodaira-Hasegawa (SH) and Approximately Unbiased (AU) tree topology tests, among them the hypothesis that Areopaguristes is monophyletic. A lack of support for the monophyly of Areopaguristes calls into question the phylogenetic validity of gill number for the differentiation of Paguristes, Areopaguristes, and Pseudopaguristes. The study was inconclusive with regard to the relationships among these three genera, but previously unknown diversity within both Paguristes and Areopaguristes was demonstrated. Existence of an undescribed species confounded under the name Paguristes tortugae Schmitt, 1933 was supported by genetics, morphology, and coloration. A second undescribed species with remarkable similarity to Areopaguristes hummi Wass, 1955 was discovered based on genetics and coloration.

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Characterization of the relationships in the pinewood nematode species complex (PWNSC) (Bursaphelenchus spp.) using a heterologous unc-22 DNA probe from Caenorhabditis elegans

Parasitology ◽

10.1017/s0031182000062636 ◽

1991 ◽

Vol 102 (2) ◽

pp. 303-308 ◽

Cited By ~ 17

Author(s):

P. Abad ◽

S. Tares ◽

N. Brugier ◽

G. De Guiran

Keyword(s):

Species Complex ◽

Nematode Species ◽

Bursaphelenchus Xylophilus ◽

Similar Species ◽

Pinewood Nematode ◽

C Elegans ◽

The World ◽

Different Populations ◽

Serious Disease

SUMMARYPine wilt is the most serious disease of native pines in Japan and potentially the most important nematode disease of conifers in the world. The pinewood nematode Bursaphelenchus xylophilus was found to be the causal agent. Difficulties arose with respect to the precise identity of some isolates of B. xylophilus and of similar species B. mucronatus and B. fraudulentus. Restriction enzyme analyses of repetitive DNA revealed bands specific for the species B. xylophilus, B. mucronatus and B. fraudulentus. Hybridization patterns obtained with unc-22 gene of C. elegans, clearly identified B. xylophilus, B. mucronatus and B. fraudulentus as well as the different geographic isolates of these species. Furthermore, it is possible to define the phylogenetic relationships between the different populations constituting the ‘pine wood nematode’ complex.

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Revision of the Parasesarma guttatum species complex reveals a new pseudocryptic species in south-east African mangroves

Invertebrate Systematics ◽

10.1071/is18028 ◽

2019 ◽

Author(s):

Sara Fratini ◽

Stefano Cannicci ◽

Francesca Porri ◽

Gianna Innocenti

Keyword(s):

New Species ◽

Indian Ocean ◽

Species Complex ◽

Taxonomic Revision ◽

Western Indian Ocean ◽

Morphological Characters ◽

East African ◽

Species Relationship ◽

Biogeographic Patterns ◽

Pseudocryptic Species

Parasesarma De Man, 1895 is the most speciose genus in the family Sesarmidae (Decapoda: Brachyura: Thoracotremata). In the western Indian Ocean, Parasesarma is represented by five species only, although some genetic evidence suggests that P. guttatum could be a species complex comprising two cryptic species. Accordingly, P. guttatum is here split into two pseudocryptic species, and a new species, Parasesarma capensis, sp. nov., is described. P. capensis, sp. nov. fills the same ecological niche as P. guttatum south of the Mozambique Channel. While variation in mitochondrial DNA and morphological differences clearly distinguish the two species, there is no nuclear genetic variation. This may reflect a short history of reproductive isolation. The distinguishing morphological characters of the new species are the 13–15 rounded tubercles on the movable finger, the upper surface of the palm with three transverse crests (one regularly tuberculate and two pectinated), and the shape of the first gonopod. Phylogenetic inference analyses show a sister-species relationship between P. guttatum and P. capensis, sp. nov., and strongly suggest that at least two East African Parasesarma species need a taxonomic revision. The description of this new sesarmid species from the south-eastern African coast sheds new light on the overall biogeographic patterns and general biodiversity of this taxon within the western Indian Ocean.

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The unusual case of the widely distributed fiddler crab Minuca rapax (Smith, 1870) from the western Atlantic: an exemplary polytypic species

Invertebrate Systematics ◽

10.1071/is18029 ◽

2018 ◽

Vol 32 (6) ◽

pp. 1465 ◽

Cited By ~ 2

Author(s):

C. L. Thurman ◽

M. J. Hopkins ◽

A. L. Brase ◽

H.-T. Shih

Keyword(s):

Gulf Of Mexico ◽

Fiddler Crab ◽

Interspecific Variation ◽

Morphological Characters ◽

Geometric Morphometric ◽

Western Atlantic ◽

Northern Portion ◽

Limited Gene Flow ◽

Different Populations ◽

The Caribbean

A classic dilemma in taxonomy is distinguishing intraspecific from interspecific variation. In order to better comprehend the process of divergence and speciation, we examine morphological, genetic, developmental and behavioural variation among related fiddler crab populations from eastern North America, the Caribbean and South America. We chose geographically remote populations that appear related to Minuca rapax (Smith, 1870). First, using females from across the range of the species, we use geometric morphometric techniques to identify regional differences in carapace shape. Second, in the northern portion of the range, the Caribbean into the Gulf of Mexico, we report variation in the relationship between corporal size and cheliped length in males. Third, we examine the major components of the courtship waves produced by males from several locations in the western Gulf of Mexico. Fourth, we compare the structure of the gastric mill between different populations in the Gulf of Mexico, the Caribbean and the Atlantic Ocean. And, fifth, we use mitochondrial 16S rDNA and cytochrome oxidase subunit I as genetic markers to define the phylogeographic relationship among specimens from more than 20 populations. From these studies, we find discrete, distinct populations across the original range of the species. In particular, populations in the northern Gulf of Mexico appear to represent a lineage that has resulted from limited gene flow and sustained selection pressures. On the basis of the observed degree of divergence, it is apparent that some separated populations in M. rapax should be recognised as evolutionary significant units. The geographic range of these populations is consistent with the historical range for Minuca virens (Salmon & Atsaides, 1968), a putative species that otherwise cannot be consistently distinguished from M. rapax based on discrete external morphological characters. This study provides evidence for M. virens as an emergent but possibly not completely isolated subclade of the M. rapax species complex.

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New Species and New Records of Sponge-Inhabiting Barnacles (Cirripedia, Balanidae, Acastinae) from Australia

Diversity ◽

10.3390/d13070290 ◽

2021 ◽

Vol 13 (7) ◽

pp. 290

Author(s):

Andrew M. Hosie ◽

Jane Fromont ◽

Kylie Munyard ◽

Diana S. Jones

Keyword(s):

New Species ◽

New Records ◽

Morphological Characters ◽

Genetic Distances ◽

Similar Species ◽

Diverse Group ◽

Undescribed Species

The subfamily Acastinae contains a diverse group of barnacles that are obligate symbionts of sponges and alcyonacean and antipatharian corals. Integrating morphological and genetic (COI) data to compare against known species, this paper reports on nine species of sponge-inhabiting barnacles of the subfamily Acastinae, including three undescribed species (Acasta caveata sp. nov., Euacasta acutaflava sp. nov., and E. excoriatrix sp. nov.) and three species previously not recorded in Australian waters (A. sandwichi, Pectinoacasta cancellorum, and P. sculpturata). The new species are distinguished from similar species by a suite of morphological characters as well as genetic distances. A lectotype for Pectinoacasta cancellorum is designated. Sponge hosts were identified for all specimens where possible and are represented by 19 species from eight families and five orders.

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Patterns of morphological diversity among and within arcid bivalve species pairs separated by the Isthmus of Panama

Journal of Paleontology ◽

10.1017/s0022336000039688 ◽

2001 ◽

Vol 75 (3) ◽

pp. 590-606 ◽

Cited By ~ 19

Author(s):

Peter B. Marko ◽

Jeremy B. C. Jackson

Keyword(s):

Morphological Variation ◽

Fossil Record ◽

Eastern Pacific ◽

Nominal Species ◽

Western Atlantic ◽

Isthmus Of Panama ◽

Species Pairs ◽

Recent Species ◽

Discriminant Analyses ◽

Collection Sites

Geminate species are morphologically similar sister-species found on either side of the Isthmus of Panama. The existence of all geminates in the tropical Eastern Pacific ocean and the Caribbean Sea is most often explained by vicariance: closure of the Central American Seaway 3.1 to 3.5 Ma simultaneously isolated populations of species with amphi-American distributions. In this paper, we test the potential of morphological measurements for discriminating between Recent geminate species pairs from three genera (Arca, Arcopsis, and Barbatia) in the bivalve family Arcidae and examine the prospects for distinguishing nominal species in the fossil record. Fourteen morphological variables were used to characterize shell shape and multivariate methods were used to discriminate between five Recent species pairs. Collection sites were also used as a priori groups for discrimination to describe patterns of intraspecific morphological variation and to evaluate differences among samples from different geographic regions.On average, 84 percent of specimens within geminate pairs are classified correctly following five separate discriminant analyses with nominal species as the grouping variable. Although all but one arcid species pair are discriminated with high statistical significance, some collection sites within species are highly morphologically distinct. Overall, a large proportion of specimens from each collection locality (79 percent on average) can be classified correctly to site although no single site possessed a multivariate centroid that was significantly different from all other conspecific centroids. The distinctiveness of some collection sites, however, raises the possibility that some nominal species may harbor cryptic species, indicating the need for wider geographic surveys of both molecular and morphological variation within geminate species pairs.The eigenvalue coefficients derived from the Recent samples of one geminate pair (Arca mutabilis and A. imbricata) were used to assess the potential for identifying arcid species in the fossil record. Discriminant analyses of fossil Arca indicate that the forms that characterize Recent A. mutabilis and A. imbricata are present in the fossil record as far back as the Late Early Miocene, in the Cantaure Formation of Venezuela. Because a deep water connection between the Eastern Pacific and Western Atlantic existed until the Middle Miocene, the morphological differences associated with Recent A. mutabilis and A. imbricata likely existed well before the rising Isthmus affected ocean circulation patterns in tropical America. Therefore, despite great overall morphological similarity, these putative geminate species likely have a time of divergence that is at least four times older than final seaway closure. The geographic distribution of fossils also suggests that morphological forms associated with each Recent species had amphi-American distributions both before and after isthmus formation but are now geographically restricted to either side of the isthmus in the Recent fauna.

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Diversity among different populations of a locally common rice (Oryza sativa L.) landrace from north-western Indian Himalayas

Plant Genetic Resources ◽

10.1017/s1479262110000109 ◽

2010 ◽

Vol 8 (2) ◽

pp. 151-158 ◽

Cited By ~ 3

Author(s):

S. Kumar ◽

A. Pandey ◽

I. S. Bisht ◽

K. V. Bhat ◽

P. S. Mehta

Keyword(s):

Oryza Sativa ◽

Oryza Sativa L ◽

Morphological Characters ◽

Ex Situ ◽

Evolutionary Forces ◽

Minimum Number ◽

Environmental Adaptations ◽

Farmer Management ◽

Different Populations ◽

On Farm

Genetic structure of five populations of a locally common rice (Oryza sativa L.) landrace Jaulia from parts of Uttarakhand state of India was studied using sequence tagged microsatellite site (STMS) markers. Of these, four populations were on-farm managed, assembled from different niche environments, and one population was conserved ex situ and represented static conservation. The 16 STMS primer pairs fully differentiated the inter- and intrapopulation diversity. A total of 72 alleles were recorded with a mean of 4.5 alleles per locus. Population wise, the total number of alleles ranged from 21 to 41, with maximum number of alleles for population IC 548358 and minimum number of alleles for population IC 100051 representing static conservation. A greater number of alleles specific to populations under farmer management could be recorded. Changes in yield parameters also seemed to be affected under farmer management besides other environmental adaptations for qualitative morphological characters. The marker diversity using STMS primer pairs indicates the genetic differentiation among populations resulting from joint effects of several evolutionary forces operating within the historical and biological context of the crop landrace. The variations in adaptations, on the other hand, indicate the degree to which populations are adapted to their environments and their potential for continued performance or as donors of characters in plant breeding. Both biotic and abiotic aspects of the environment are involved.

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Resurrection of Pilumnus vinaceus A. Milne-Edwards, 1880 (Brachyura: Pilumnidae) using integrative evidence from molecular and morphology

Zootaxa ◽

10.11646/zootaxa.5047.5.4 ◽

2021 ◽

Vol 5047 (5) ◽

pp. 547-556

Author(s):

TATIANA MAGALHÃES ◽

JOÃO A. F. PANTALEÃO ◽

FERNANDO L. MANTELATTO

Keyword(s):

Molecular Markers ◽

Morphological Characters ◽

Junior Synonym ◽

Western Atlantic

The hairy crab Pilumnus vinaceus A. Milne-Edwards, 1880, previously considered to be a junior synonym of Pilumnus dasypodus Kingsley, 1879 by Rathbun (1897) is here resurrected. Pilumnus vinaceus can be distinguished from the known western Atlantic species (including P. dasypodus) based on morphological characters and molecular markers. This action increases number of reported species of Pilumnus in the western Atlantic to nineteen.

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