The “sexy shrimp”
Coral reefs in all tropical oceans.
Specimens of
We found evidence for at least five cryptic lineages (9%–22%
- Award ID(s):
- 1856245
- NSF-PAR ID:
- 10297339
- Date Published:
- Journal Name:
- Coral Reefs - this is not a proceedings, it is a journal, but it is not in your dropdown!?
- Volume:
- not assigned yet
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract Aim Thor amboinensis is currently considered a single circumtropical species. However, the tropical oceans are partitioned by hard and soft barriers to dispersal, providing ample opportunity for allopatric speciation. Herein, we test the null hypothesis thatT. amboinensis is a single global species, reconstruct its global biogeographical history, and comment on population‐level patterns throughout the Tropical Western Atlantic.Location Methods Thor amboinensis were obtained through field collection and museum holdings. We used one mitochondrial (COI ) and two nuclear (NaK, enolase) gene fragments for global species delimitation and phylogenetic analyses (n = 83 individuals, 30 sample localities), while phylogeographical reconstruction in theTWA was based onCOI only (n = 303 individuals, 10 sample localities).Results COI pairwise sequence divergence): four in the Indo‐West Pacific and one in the Tropical Western Atlantic. Phylogenetic reconstruction revealed that endemic lineages from Japan and the South Central Pacific are more closely related to the Tropical Western Atlantic lineage than to a co‐occurring lineage that is widespread throughout the Indo‐West Pacific. Concatenated and species tree phylogenetic analyses differ in the placement of an endemic Red Sea lineage and suggest alternate dispersal pathways into the Atlantic. Phylogeographical reconstruction throughout the Tropical Western Atlantic reveals little genetic structure over more than 3,000 km.Main conclusions Thor amboinensis is a species complex that has undergone a series of allopatric speciation events and whose members are in secondary contact in the Indo‐West Pacific. Nuclear‐ and mitochondrial‐ gene phylogenies show evidence of introgression between lineages inferred to have been separated more than 20 Ma. Phylogenetic discordance between multi‐locus analyses suggest thatT. amboinensis originated in the Tethys sea and dispersed into the Atlantic and Indo‐West Pacific through the Tethys seaway or, alternatively, originated in the Indo‐West Pacific and dispersed into the Atlantic around South Africa. Population‐level patterns in the Caribbean indicate extensive gene flow across the region. -
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Abstract Knowledge of the biogeography of marine taxa has lagged significantly behind terrestrial ecosystems. A hotspot of marine biodiversity associated with coral reefs is known in the Coral Triangle of the Indo-West Pacific, but until now there was little data with which to evaluate broad patterns of species richness in the coastal fauna of ecosystems other than coral reefs. This data is critically needed for fauna with low functional redundancy like that of mangroves, that are vulnerable to habitat loss and rising sea levels. Here we show that the diversity of mangrove fauna is characterized by two distinct hotspots in the Indo-West Pacific, associated with two habitat types: fringe mangroves in the Coral Triangle, and riverine mangroves in the Strait of Malacca, between the west coast of Peninsular Malaysia and Sumatra. This finding, based on a family of slugs of which the systematics has been completely revised, illustrates an unexpected biogeographic pattern that emerged only after this taxon was studied intensively. Most organisms that live in the mangrove forests of Southeast Asia remain poorly known both taxonomically and ecologically, and the hotspot of diversity of onchidiid slugs in the riverine mangroves of the Strait of Malacca indicates that further biodiversity studies are needed to support effective conservation of mangrove biodiversity.
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Lobophora is a common tropical to temperate genus of brown algae found in a plethora of habitats including shallow and deep‐water coral reefs, rocky shores, mangroves, seagrass beds, and rhodoliths beds. Recent molecular studies have revealed thatLobophora species diversity has been severely underestimated. Current estimates of the species numbers range from 100 to 140 species with a suggested center of diversity in the Central Indo‐Pacific. This study used three molecular markers (cox 3,rbc L,psb A), different single‐marker species delimitation methods (GMYC ,ABGD ,PTP ), and morphological evidence to evaluateLobophora species diversity in the Western Atlantic and the Eastern Pacific oceans.Cox 3 provided the greatest number of primary species hypotheses(PSH), followed byrbc L and thenpsb A.GMYC species delimitation analysis was the most conservative across all three markers, followed byPTP , and thenABGD . The most informative diagnostic morphological characters were thallus thickness and number of cell layers in both the medulla and the dorsal/ventral cortices. Following a consensus approach, 14 distinctLobophora species were identified in the Western Atlantic and five in the Eastern Pacific. Eight new species from these two oceans were herein described:L. adpressa sp. nov.,L. cocoensis sp. nov.,L. colombiana sp. nov.,L. crispata sp. nov.,L. delicata sp. nov.,L. dispersa sp. nov.,L. panamensis sp. nov., andL. tortugensis sp. nov. This study showed that the best approach to confidently identifyLobophora species is to analyzeDNA sequences (preferablycox 3 andrbc L) followed by comparative morphological and geographical assessment. -
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Abstract Aim Historical processes that shaped current diversity patterns of seaweeds remain poorly understood. Using Dictyotales, a globally distributed order of brown seaweeds as a model, we test if historical biogeographical and diversification patterns are comparable across clades. Dictyotales contain some 22 genera, three of which,
Dictyota ,Lobophora andPadina , are exceptionally diverse. Specifically, we test whether the evolutionary processes that shaped the latitudinal diversity patterns in these clades are in line with the tropical conservatism, out‐of‐the‐tropics or diversification rate hypotheses.Location Global coastal benthic marine environments.
Taxon Dictyotales (Phaeophyceae).
Methods Species diversity was inferred using DNA‐based species delineation, addressing cryptic diversity and circumventing taxonomic problems. A six‐gene time‐calibrated phylogeny, distribution data of 3,755 specimens and probabilistic modelling of geographical range evolution were used to infer historical biogeographical patterns. The phylogeny was tested against different trait‐dependent models to compare diversification rates for different geographical units as well as different thermal affinities.
Results Our results indicate that Dictyotales originated in the Middle Jurassic and reach a current peak of species diversity in the Central Indo‐Pacific. Ancestral range estimation points to a southern hemisphere origin of Dictyotales corresponding to the tropical southern Tethys Sea. Our results demonstrate that diversification rates were generally higher in tropical regions, but increased diversification rates in different clades are driven by different processes. Our results suggest that three major clades underwent a major diversification burst in the early Cenozoic, with
Dictyota andPadina expanding their distribution into temperate regions whileLobophora retained a predominantly tropical niche.Main conclusions Our results are consistent with both the tropical conservatism hypothesis, in which clades originate and remain in the tropics (
Lobophora ), and the out‐of‐the‐tropics scenario, where taxa originate and expand towards the temperate regions while preserving their presence in the tropics (Dictyota ,Padina ). -
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Abstract The northern temperate genus
Dracocephalum consists of approximately 70 species mainly distributed in the steppe‐desert biomes of Central and West Asia and the alpine region of the Qinghai‐Tibetan Plateau (QTP). Previous work has shown thatDracocephalum is not monophyletic and might includeHyssopus andLallemantia . This study attempts to clarify the phylogenetic relationships, diversification patterns, and the biogeographical history of the three genera (defined asDracocephalum s.l.). Based on a sampling of 66 taxa comprising more than 80% from extant species ofDracocephalum s.l., morphological, phylogenetic (maximum parsimony, likelihood, and Bayesian inference based on nuclear ITS and ETS, plastidrpl32‐trnL ,trnL‐trnF ,ycf1 , andycf1‐rps15 , and two low‐copy nuclear markersAT3G09060 andAT1G09680 ), molecular dating, diversification, and ancestral range estimation analyses were carried out. Our results demonstrate that bothHyssopus andLallemantia are embedded withinDracocephalum and nine well‐supported clades can be recognized withinDracocephalum s.l. Analyses of divergence times suggest that the genus experienced an early rapid radiation during the middle to late Miocene with major lineages diversifying within a relatively narrow timescale. Ancestral area reconstruction analyses indicate thatDracocephalum s.l. originated in Central and West Asia and southern Siberia, and dispersed from Central and West Asia into the QTP and adjacent areas twice independently during the Pliocene. The aridification of the Asian interior possibly promoted the rapid radiation ofDracocephalum within this region, and the uplift of the QTP appears to have triggered the dispersal and recent rapid diversification of the genus in the QTP and adjacent regions. Combining molecular phylogenetic and morphological evidence, a revised infrageneric classification ofDracocephalum s.l. is proposed, which recognizes nine sections within the genus.
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Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/https://doi.org/10.1007/s00338-021-02163-1
