https://orcid.org/0000-0002-2233-9596
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ABSTRACT
Avrainvillea is a green macroalgal genus of the family Dichotomosiphonaceae (order Bryopsidales). Many species have been morphologically described, but few studies have addressed the genetic diversity of this genus. Based on a rich collection of specimens from the tropical Western Atlantic, Indian and Pacific Oceans, we aimed to (1) reassess Avrainvillea species diversity through species delimitation analyses, (2) update their distribution ranges, (3) reconstruct the species phylogenetic relationships, based on a concatenated multilocus matrix (tufA, rbcL and 18S rDNA) and (4) revise their taxonomy and describe new species where necessary. Our species delimitation approach highlighted 23 secondary species hypotheses in our collection, including nine known and currently accepted species, four species complexes (A. amadelpha, A. lacerata, A. erecta-obscura and A. mazei-nigricans), and eight new species for which we provide descriptions: A. laciniata (Papua New Guinea), A. minima and A. pyrochroma (Madagascar), A. mollis and A. kanakiensis (New Caledonia), A. pavonina (Fiji), A. spongiosa (Pacific) and A. corticata (Indo-Pacific). We also propose the resurrection of A. gracillima Børgesen, the reinstatement of Avrainvillea lacerata var. robustior A.Gepp & E.S.Gepp, and the synonymy of A. rotumensis A.D.R.N’Yeurt, D.S.Littler & Littler with A. pacifica A.Gepp & E.S.Gepp. We complemented the taxonomic work by providing a contemporary dichotomous key for morphological identification of all extant species. Our multilocus phylogeny included 25 species of Dichotomosiphonaceae and recovered Avrainvillea as a polyphyletic group, divided into three distinct clades, with Cladocephalus luteofuscus positioned within the group. The species determined using the species delimitation approach were all monophyletic and 19 of them were highly supported. For the first time, this study also provided genetic sequences for A. asarifolia, A. clavatiramea, A. digitata, A. elliottii, A. fulva, A. gracillima, A. geppiorum, A. pacifica and A. obscura.
HIGHLIGHTS
• Avrainvillea is not monophyletic.
• Reassessment of Avrainvillea species diversity delimited 23 secondary species hypotheses.
• Eight new species of Avrainvillea were discovered in the Indo-Pacific.
Acknowledgements
Samples were collected by several collectors and the authors are particularly grateful to Line Le Gall, Hélène Magalon, Lydiane Mattio, Serge Andréfouët, Elvan Ampou, Gustave Paulay and Heroen Verbruggen for providing additional samples or sequences.
For their help with the Latin translations to name the new species, we thank Francesca Benzoni and Lydiane Mattio. We are also grateful to Lydiane Mattio (blue[c]weed) for revising the English and providing useful comments to improve the manuscript.
Most of the molecular analyses were performed at the Plateforme du Vivant (CRESICA-IRD Noumea). Although most of the sequences were obtained by LL, we also would like to thank Claire Bonneville and Gregoire Davignon for the additional sequences they produced. Molecular data of a few other samples (PC) were produced by the Service de Systématique Moléculaire of the Muséum National d’Histoire Naturelle (CNRS – UMS 2700).
The following campaigns made it possible to build this rich dataset: Bunaken, 2014: INDESO project (research permits 133/SIP/FRP/SM/V/2015 and 918/BLITBANKKP/II/2016 issued by the Indonesian government and under a material transfer agreement between BALITBANG KP (now BRSDM KP, Ministry of Maritime Affairs and Fisheries) and IRD); Caribbean Islands, 2015: R/V Antea, PACOTILLES, doi: 10.17600/15005200); Fiji, 2007: R/V Alis, BSM-Fidji, doi: 10.17600/7100030; French Polynesia, 2008: Moorea-biocode; Guadeloupe, 2014: R/V Antea, KARUBENTHOS organized by Onema and MNHN, doi: 10.17600/15005400; Kavieng, 2014: doi:10.17600/14004400; Madagascar, 2010: Atimo Vatae, doi: 10.17600/10110040; 2016: R/V Antea, MAD, doi: 10.17600/16004700; Madang, 2012: R/V Alis, NUIGUINI campaign, doi:10.17600/12100070; Mayotte, 2010: TARA; 2016: SIREME; New Caledonia, 2005: R/V Alis, BSM-LOYAUTE, doi: 10.17600/5100030; 2012: CORALCAL4, doi: 10.17600/12100060; 2013: LOF; 2015: R/V Alis, CHEST, doi: 10.17600/15004500; 2017: R/V Alis PostBlanco1 & TARA-NC; Scattered Islands, Juan de Nova Is., 2013: BIORECIE; Tuvalu: CLS, ESA grant number no. 4000110904/14/I-AM; Vanuatu, 2006: SANTO, doi: 10.17600/6100100.
Disclosure statement
No potential conflict of interest was reported by the authors.
Supplementary material
The following supplementary material is accessible via the Supplementary Content tab on the article’s online page at https://doi.org/10.1080/09670262.2023.2164907.
Supplementary table S1: List of vouchers included in the study with sample ID, Herbarium ID, species identifica- 1620 tion, collection localities, GenBank accession numbers (or BOLD sequence ID for those not submitted), and the corresponding SSH number.
Supplementary table S2: Name, nucleotide sequence and reference of the primers used for the amplification of the 1625 tufA, rbcL, and 18S rDNA markers.
Supplementary table S3: Details of incongruence resolution process and species assignment decision.
Supplementary table S4: Table of interspecific genetic distances between species for tufA and rbcL markers (pre- 1630 sented as % similarity).
Supplementary table S5: Morpho-anatomical observations for all clades, along with currently accepted species descriptions.
Supplementary table S6: Summary of Olsen-Stojkovic’s groups and the three phylogenetic clusters (A, B & C) found in this study, with the list of the corresponding species and the shared morpho-anatomical characters.
Supplementary fig. S1: Species delimitation results obtained with the three methods (GMYC, ASAP and PTP) for the tufA dataset. The tree is the MCCT from the BEAST analyses. The numbers in brackets indicate the supplementary identical haplotypes. Black bars indicate PSHs retained as SSHs, following the majority rule, while blue bars represent the PSHs retained as SSHs although not favoured by the majority rule. Grey bars are alternative PSHs not retained. The defined SSHs (clades) are indicated in the right column, with morpho-anatomical congruence (M column, v: specimens observations matched with existing species diagnoses; x: no match with existing diagnoses; R: proposition of species resurrection; S: proposition of synonyms; *: incongruences), as well as species identification.
Supplementary fig. S2: ML gene-tree obtained with RaxML for tufA dataset, using the GTR + G evolutionary model and 1000 bootstrap (bs) iterations. Bootstraps values (bs) are reported at the nodes if > 50.
Supplementary fig. S3: Species delimitation results obtained with the three methods (GMYC, ASAP and 1660 PTP) for the rbcL dataset. The tree is the MCCT from the BEAST analyses. Numbers in brackets indicate additional identical haplotypes. Black bars indicate partitions retained as SSHs, following the majority rule; blue bars represent the partition retained as SSHs but not favoured by the majority rule. Grey bars are alternative partition schemes not retained. The defined SSHs (clades) are indicated in the column to the right, with morpho-anatomical congruence (v: specimens observations matched with existing species diagnoses; x: no match with existing diagnoses; R: proposition of species resurrection; S: proposition of new synonyms; *: incongruences), and species identification.
Supplementary fig. S4: ML gene-tree obtained with RaxML for rbcL dataset using the GTR + G evolutionary model and 1000 bootstrap (bs) iterations. Bootstraps values (bs) are reported at the nodes if > 50.
Supplementary fig. S5: ML phylogeny of the Dichotomosiphonaceae obtained from the multilocus matrix (tufA, rbcL, and 18S rDNA) with bootstrap values (bs) indicated at the nodes. The position of Cladocephalus luteofuscus among the Avrainvillea species is framed in blue. GenBank sequence assignments that need verification are indicated in grey. Nodes A, B, C indicate Avrainvillea species groups. The outgroup species were Bryopsis plumosa, Codium taylorii, C. duthieae, C. platylobium, Caulerpa taxifolia, C. sertularioides, and C. verticillata. Abbreviations: FP: French Polynesia, NC: New Caledonia, PNG: Papua New Guinea
Supplementary fig. S6: BI phylogeny of the Dichotomosiphonaceae obtained from the multilocus matrix (tufA, rbcL, and 18S rDNA) with Posterior probabilities (PP) indicated at the nodes. The position of Cladocephalus luteofuscus among Avrainvillea species is framed in blue. GenBank sequence assignments that need verification are indicated in grey. Nodes A, B, C indicate the different Avrainvillea species groups. The outgroup species were Bryopsis plumosa, Codium taylorii, C. duthieae, C. platylobium, Caulerpa taxifolia, C. sertularioides, and C. verticillata. Abbreviations: FP: French Polynesia, NC: New Caledonia, PNG: Papua New Guinea
Supplementary fig. S7: Cladocephalus luteofuscus (PC0143565). A: Overall view of the pseudo-cortex formed by interwoven cortical siphons and appendages in the blade; B–D: Detail of the appendages of blade siphons. Scale bars: A: 167 μm; B: 66 >m; C: 88 >m; D: 45 >m
Supplementary fig. S8: Distribution map of Avrainvillea species included in this study, based on DNA data.
Supplementary figs S9–S19. Avrainvillea gracillima.
Supplementary fig. S9. Habit in situ (NOU203318).
Supplementary fig. S10. Habit ex situ (NOU203318).
Supplementary figs S11-S12. Blade siphons subcylindrical, torulose or tortuous (S11: NOU203318; S12: NOU203335).
Supplementary fig. S13. Dichotomies with supradichotomal constrictions (NOU203335). Supplementary figs S14–S15. Tortuous or bent apices (NOU203318).
Supplementary figs S16–S17. Stipe siphons cylindrical to torulose (S16: NOU203318; S17: NOU203335).
Supplementary fig. S18. Dichotomies with symmetrical constrictions in stipe siphons (NOU203318).
Supplementary fig. S19. Primary rhizoids distorted, sec-ondary rhizoids torulose to cylindrical (NOU203335). Scale 1720 bars: 9: 0.6 cm; 10: 0.45 cm; 11–12: 125 μm; 13: 80 μm; 14–15: 66 m; 16–18: 100 μm; 19: 150 μm.
Supplementary figs S20–S27. Avrainvillea lacerata var. robustior. Supplementary fig. S20. In situ habit (NOU203629). Supplementary fig. S21. Herbarium speci-men (NOU203629). Supplementary fig. S22. Torulose cortical blade siphons (NOU203629). Supplementary figs S23–S24. Long-necked constrictions at dichotomies and supradichotomal swelling (S23 : NOU203628, S24 : NOU203629). Supplementary fig. S25. Cylindrical to tor-ulose stipe siphons (NOU203628). Supplementary figs S26–S27. Rhizoids tortuous to distorted (NOU203629). Scale bars: 20: 0.93 cm; 21: 1.28 cm; 22: 250 μm; 23: 40 μm; 24: 37.5 μm; 25: 300 μm; 26: 133 μm; 27: 266 μm.
Supplementary figs S28–S36. Avrainvillea pacifica.
Supplementary fig. S28. In situ habit of a peltate individual (NOU213749). Supplementary fig. S29. Herbarium specimen with cordato-semirotundate habit (NOU203445).
Supplementary figs S30–31. Blade siphons torulose to moniliform or tortuous (NOU203450). Supplementary fig. S32. Dichotomies wide-angled (NOU203450). Supplementary figs S33–S34. Moniliform medullary stipe siphons and cortical cylindrical, tortuous or moniliform cortical siphons (NOU203450). Supplementary fig. S35. Rhizoids moniliform to tortuous (NOU203450).
Supplementary fig. S36. Rhizoids with or without supradichotomal constrictions and blunt apices (NOU203450). Scale bars: 28: 1,375 cm; 29: 2,59 cm; 30: 150 μm; 31: 166 μm; 32: 60 μm; 33: 171 μm; 34–35: 166 μm; 36: 250 μm.
Supplementary data S1: List of specimens examined for each new or revised species.
Author contributions
L. Lagourgue: treatment and analyses of molecular data (species delimitation, phylogeny), morphological analyses, taxonomic diagnosis, original concept, drafting and editing manuscript; F. Rousseau: sample collection, acquisition of genetic sequences, morphological observations, review and editing of manuscript; M. Zubia: sample collection, review and editing of manuscript; C.E. Payri: sample collection, morphological observations, funding acquisition, original concept, review and editing of manuscript.