More Like this

1. Diversification and distribution of gall crabs (Brachyura: Cryptochiridae: Opecarcinus) associated with Agariciidae corals.

   https://doi.org/https://doi.org/10.1007/s00338-021-02163-1  

   Xu, T.; Bravo, H.; Paulay, G.; van der Meij, S.E.T. (August 2021, Coral Reefs - this is not a proceedings, it is a journal, but it is not in your dropdown!?)

   null (Ed.)

   Coral reefs are home to the greatest diversity of marine life, and many species on reefs live in symbiotic associations. Studying the historical biogeography of symbiotic species is key to unravelling (potential) coevolutionary processes and explaining species richness patterns. Coral-dwelling gall crabs (Cryptochiridae) live in obligate symbiosis with a scleractinian host, and are ideally suited to study the evolutionary history between heterogeneous taxa involved in a symbiotic relationship. The genus Opecarcinus Kropp and Manning, 1987, like its host coral family Agariciidae, occurs in both Indo-Pacific and Caribbean seas, and is the only cryptochirid genus with a circumtropical distribution. Here, we use mitochondrial and nuclear DNA gene fragments of Opecarcinus specimens sampled from 21 Indo-Pacific localities and one Atlantic (Caribbean) locality. We applied several species delimitation tests to characterise species diversity, inferred a Bayesian molecular-clock time-calibrated phylogeny to estimate divergence times and performed an ancestral area reconstruction. Time to the most recent common ancestor (tMRCA) of Opecarcinus is estimated at 15−6 Mya (middle Miocene—late Miocene). The genus harbours ~ 15 undescribed species as well as several potential species complexes. There are indications of strict host-specificity patterns in certain Opecarcinus species in the Indo-Pacific and Atlantic, however, a robust phylogeny reconstruction of Agariciidae corals—needed to test this further—is currently lacking. The Indo-West Pacific was inferred to be the most probable ancestral area, from where the Opecarcinus lineage colonised the Western Atlantic and subsequently speciated into O. hypostegus. Opecarcinus likely invaded from the Indo-West Pacific across the East Pacific Barrier to the Atlantic, before the full closure of the Isthmus of Panama. The subsequent speciation of O. hypostegus, is possibly associated with newly available niches in the Caribbean, in combination with genetic isolation following the closure of the Panama Isthmus. 

   more » « less
2. Gene flow creates a mirage of cryptic species in a Southeast Asian spotted stream frog complex

   https://doi.org/10.1111/mec.15603  

   Chan, Kin O.; Hutter, Carl R.; Wood, Jr, Perry L.; Grismer, L. L.; Das, Indraneil; Brown, Rafe M. (September 2020, Molecular Ecology)

   Abstract Most new cryptic species are described using conventional tree‐ and distance‐based species delimitation methods (SDMs), which rely on phylogenetic arrangements and measures of genetic divergence. However, although numerous factors such as population structure and gene flow are known to confound phylogenetic inference and species delimitation, the influence of these processes is not frequently evaluated. Using large numbers of exons, introns, and ultraconserved elements obtained using the FrogCap sequence‐capture protocol, we compared conventional SDMs with more robust genomic analyses that assess population structure and gene flow to characterize species boundaries in a Southeast Asian frog complex (Pulchrana picturata). Our results showed that gene flow and introgression can produce phylogenetic patterns and levels of divergence that resemble distinct species (up to 10% divergence in mitochondrial DNA). Hybrid populations were inferred as independent (singleton) clades that were highly divergent from adjacent populations (7%–10%) and unusually similar (<3%) to allopatric populations. Such anomalous patterns are not uncommon in Southeast Asian amphibians, which brings into question whether the high levels of cryptic diversity observed in other amphibian groups reflect distinct cryptic species—or, instead, highly admixed and structured metapopulation lineages. Our results also provide an alternative explanation to the conundrum of divergent (sometimes nonsister) sympatric lineages—a pattern that has been celebrated as indicative of true cryptic speciation. Based on these findings, we recommend that species delimitation of continuously distributed “cryptic” groups should not rely solely on conventional SDMs, but should necessarily examine population structure and gene flow to avoid taxonomic inflation. 

   more » « less
3. Genetic structuring and species boundaries in the Atlantic stony coral Favia (Scleractinia, Faviidae)

   https://doi.org/10.1111/zsc.12652  

   Adam, Carolina de Lima; Toonen, Robert J.; Carlon, David B.; Zilberberg, Carla; Barbeitos, Marcos Soares (January 2024, Zoologica Scripta)

   Abstract Scleractinian corals are the main modern builders of coral reefs, which are major hot spots of marine biodiversity. Southern Atlantic reef corals are understudied compared to their Caribbean and Indo‐Pacific counterparts and many hypotheses about their population dynamics demand further testing. We employed thousands of single nucleotide polymorphisms (SNPs) recovered via ezRAD to characterize genetic population structuring and species boundaries in the amphi‐Atlantic hard coral genusFavia. Coalescent‐based species delimitation (BFD* – Bayes Factor Delimitation) recoveredF. fragumandF. gravidaas separate species. Although our results agree with depth‐related genetic structuring inF. fragum, they did not support incipient speciation of the ‘tall’ and ‘short’ morphotypes. The preferred scenario also revealed a split between two main lineages ofF. gravida, one from Ascension Island and the other from Brazil. The Brazilian lineage is further divided into a species that occurs throughout the Northeastern coast and another that ranges from the Abrolhos Archipelago to the state of Espírito Santo. BFD* scenarios were corroborated by analyses of SNP matrices with varying levels of missing data and by a speciation‐based delimitation approach (DELINEATE). Our results challenge current notions about Atlantic reef corals because they uncovered surprising genetic diversity inFaviaand rejected the long‐standing hypothesis that Abrolhos Archipelago may have served as a Pleistocenic refuge during the last glaciations. 

   more » « less
4. The little shrimp that could: phylogeography of the circumtropical Stenopus hispidus (Crustacea: Decapoda), reveals divergent Atlantic and Pacific lineages

   https://doi.org/10.7717/peerj.4409  

   Dudoit, ‘Ale‘alani; Iacchei, Matthew; Coleman, Richard R.; Gaither, Michelle R.; Browne, William E.; Bowen, Brian W.; Toonen, Robert J. (January 2018, PeerJ)

   The banded coral shrimp, Stenopus hispidus (Crustacea: Decapoda: Stenopodidea) is a popular marine ornamental species with a circumtropical distribution. The planktonic larval stage lasts ∼120–253 days, indicating considerable dispersal potential, but few studies have investigated genetic connectivity on a global scale in marine invertebrates. To resolve patterns of divergence and phylogeography of S. hispidus , we surveyed 525 bp of mitochondrial cytochrome c oxidase subunit I (COI) from 198 individuals sampled at 10 locations across ∼27,000 km of the species range. Phylogenetic analyses reveal that S. hispidus has a Western Atlantic lineage and a widely distributed Indo-Pacific lineage, separated by sequence divergence of 2.1%. Genetic diversity is much higher in the Western Atlantic ( h = 0.929; π  = 0.004) relative to the Indo-Pacific ( h = 0.105; π  < 0.001), and coalescent analyses indicate that the Indo-Pacific population expanded more recently (95% HPD (highest posterior density) = 60,000–400,000 yr) than the Western Atlantic population (95% HPD = 300,000–760,000 yr). Divergence of the Western Atlantic and Pacific lineages is estimated at 710,000–1.8 million years ago, which does not readily align with commonly implicated colonization events between the ocean basins. The estimated age of populations contradicts the prevailing dispersal route for tropical marine biodiversity (Indo-Pacific to Atlantic) with the oldest and most diverse population in the Atlantic, and a recent population expansion with a single common haplotype shared throughout the vast Indian and Pacific oceans. In contrast to the circumtropical fishes, this diminutive reef shrimp challenges our understanding of conventional dispersal capabilities of marine species. 

   more » « less
5. Phylogenetic status of some unique species representing Blapstinina Mulsant & Rey (Tenebrionidae: Blaptinae: Opatrini), and implications for continued study of the subtribe

   https://doi.org/10.11646/zootaxa.5000.5.2  

   KAMIŃSKI, MARCIN JAN; LUMEN, RYAN; KANDA, KOJUN; SMITH, AARON DENNIS (February 2022, Zootaxa)

   Blapstinus Dejean is the most taxonomically challenging genus within Blapstinina Mulsant & Rey (Tenebrionidae: Opatrini). With over 120 species, it is widely distributed throughout the Americas, with representatives reaching Canada on the northern range edge, and Argentina, Chile, and Uruguay in the south. Traditionally, Blapstinus has been distinguished from other blapstinoid beetles via well-developed metathoracic wings and their lack of synapomorphies present in other genera; however, fused and tapering aedeagal parameres were recently introduced as a potential autapomorphy for the genus. This study used molecular data (nuclear ribosomal 28S, cytochrome oxidase subunit II (COII), arginine kinase (ArgK), carbomyl-phosphate synthetase domain of rudimentary (CAD), and wingless (wg)) to investigate the phylogenetic placement and taxonomic status of three Blapstinus species with distinct male genitalic morphology, i.e. Blapstinus tibialis Champion (USA), B. grandis Champion (Mexico, Nicaragua), and B. punctulatus Solier (Argentina, Bolivia, Brazil, Chile, Uruguay). Analyses highlight the phylogenetic informativeness of the aedeagal morphology within the subtribe, and support an urgent need for taxonomic studies of South American taxa. Blapstinus tibialis and B. grandis were recovered as a specific lineage within Blapstinus that can be easily distinguished from remaining congeners by having tridentate parameres. A lectotype for B. grandis is designated to fix the taxonomic status of this species. Blapstinus punctulatus was recovered outside of its current genus which, along with aedeagal morphology, supports a change of status of the species. As a result, the following synonymy and combinations are introduced: Lodinus Mulsant and Rey stat. restit. (=Austrocaribius Marcuzzi syn. nov.), Lodinus araguae (Marcuzzi) comb. et stat. nov., L. punctulatus comb. nov., L. venezuelensis (Marcuzzi) comb. nov. Lectotypes for Lodinus nigroaeneus Mulsant and Rey, L. araguae, and L. punctulatus are designated to fix the taxonomic status of these species. 

   more » « less