Avrainvillea erecta Gepp & Gepp 1911

Wade, Rachael M, Spalding, Heather L, Peyton, Kimberly A, Foster, Kevin, Sauvage, Thomas, Ross, Matthew & Sherwood, Alison R, 2018, A new record of Avrainvilleacf. erecta (Berkeley) A. Gepp & E. S. Gepp (Bryopsidales, Chlorophyta) from urbanized estuaries in the Hawaiian Islands, Biodiversity Data Journal 6, pp. 21617-21617 : 21617

Avrainvillea erecta Gepp & Gepp 1911

Materials

Type status: Other material. Occurrence: catalogNumber: BISH768278-83 ; recordedBy: Matthew Ross; individualCount: 6; otherCatalogNumbers: ARS09414,-09417,-09418, -09429,-09431,-09432; associatedSequences: MF872080-85, MF872105-110; Taxon: scientificName: Avrainvillea cf. erecta; kingdom: Plantae; phylum: Chlorophyta; class: Ulvophyceae; order: Bryopsidales; family: Dichotomosiphonaceae; genus: Avrainvillea; specificEpithet: erecta; scientificNameAuthorship: (Berkeley) A. Gepp & E.S. Gepp; Location: country: USA; municipality: Honolulu; locality: Malama Bay, seaward of Ke'ehi Lagoon ; minimumDepthInMeters: 25; maximumDepthInMeters: 40; decimalLatitude: 21.29; decimalLongitude: 157.9205; georeferenceProtocol: GPS; Identification: identifiedBy: Rachael M. Wade; dateIdentified: May-2017; identificationReferences: Olsen-Stojkovich 1985; Event: eventDate: Apr-22-2017; Record Level: language: en; basisOfRecord: PreservedSpecimen Type status: Other material. Occurrence: catalogNumber: BISH768338-9 ; recordedBy: Kimberly Peyton, Kevin Foster, Paul Murakawa; individualCount: 2; otherCatalogNumbers: ARS09436-7; associatedSequences: MF969093-6; Taxon: scientificName: Avrainvillea cf. erecta; kingdom: Plantae; phylum: Chlorophyta; class: Ulvophyceae; order: Bryopsidales; family: Dichotomosiphonaceae; genus: Avrainvillea; specificEpithet: erecta; scientificNameAuthorship: (Berkeley) A. Gepp & E.S. Gepp; Location: country: USA; municipality: Honolulu; locality: Malama Bay, Honolulu Harbor ; minimumDepthInMeters: 12; maximumDepthInMeters: 15; decimalLatitude: 21.30; decimalLongitude: 157.8689; georeferenceProtocol: GPS; Identification: identifiedBy: Rachael M. Wade; dateIdentified: Aug-2017; identificationReferences: Olsen-Stojkovich 1985; Event: eventDate: Oct-15-2015; Record Level: language: en; basisOfRecord: PreservedSpecimen Type status: Other material. Occurrence: associatedSequences: MH938452; Taxon: scientificName: Avrainvilleaerecta; acceptedNameUsage: Avrainvilleaerecta Gepp & Gepp 1911; originalNameUsage: ChloroplegmapapuanumZanaradini 1878; kingdom: Plantae; phylum: Chlorophyta; class: Ulvophyceae; order: Bryopsidales; family: Dichotomosiphonaceae; genus: Avrainvillea; specificEpithet: erecta; taxonomicStatus: heterotypic synonym; Location: waterBody: Pacific Ocean; country: Indonesia; stateProvince: Papua; Identification: identifiedBy: Zanardini; dateIdentified: 1878; Event: year: 1872; month: May; fieldNotes: Collected by Odoardo Beccari; Record Level: institutionID: BM000561613; basisOfRecord: PreservedSpecimen

Description

In situ observations

During the 2014 seagrass community survey, the newly discovered Avrainvillea sp. was observed at six of 16 survey sites in the Honolulu Harbor entrance channel from 12-15m depths (four "Control Sites", two "Impact Sites"; Suppl. material 1). The two morphologies (blade-like versus assemblage of loose siphons) differed in their exposure to water flow - individuals with a completely formed blade were often elevated and fully exposed to water motion, while individuals with a loose assemblage of siphons were in depressions or divots and therefore protected (K. Peyton, unpublished data). This water motion effect was also supported by informal experimentation: in water tables without water flow, blades were observed to unweave and become loose assemblages while specimens with water flow maintained the blade morphology (K. Peyton, unpublished data).

In 2017, the newly recorded Avrainvillea sp. was observed as single individuals or in patches with 10-20 individuals per m2 (estimated visually) in areas with deep sand (Fig. 2a, b). The dominant vegetation in these sand beds was the seagrass Halophila decipiens Ostenfeld, patches of the macroalga Halimeda kanaloana Vroom, and an unidentified Udotea sp. Several individuals were observed with feeding scars (large bite marks), giving some thalli a U-shaped appearance. The holdfasts of larger, more mature individuals protruded from the sediment by approximately 1-5 cm, creating a conical mound at the base of the alga. Individuals were generally clean and not heavily epiphytized. The two morphologies at this location experienced very little water motion due to attenuation of wave motion with depth, and therefore were most likely the result of differences in age. The individuals with spherical assemblages of loose siphons were consistently much smaller in thallus size than the well-formed blade morphology.

Morphological characterization

The specimens were olive-green upon collection and dried to a darker green with fulvous, or tawny, coloration (Fig. 2c, d). Specimens were categorized as mature adults (BISH768278), immature adults (BISH768279-80) or juveniles (BISH768281-3). Adult individuals, both mature and immature, ranged in overall length from 6.7-15.8 cm; frond length ranged from 3.6-10.8 cm. Each adult thallus was distinctly differentiated into a holdfast, stipe, and blade. The rhizomatous holdfasts comprised up to 46% of the total thallus length. The thin stipes of adult individuals supported a lightly zonate and reniform to sub-reniform blade; margins appeared to be composed of loose aggregates of siphons, but not necessarily lacerate. Individuals that appeared to be juveniles consisted only of a holdfast and a spherical assemblage of loose siphons, which appeared to be in the beginning stages of forming a blade. Siphons throughout the specimens (e.g. margin, blade, stipe, and holdfast) were mostly cylindrical to slightly torulose and measured in width 11.1-(25.4-59.1)-93.1 µm with acute and deep constrictions above the dichotomies (Fig. 2e). Constrictions were also common below the dichotomy, except in the holdfast siphons. Apices were primarily rounded, but also rarely blunt or sub-clavate. Siphons appeared olive green, transparent, or fulvus, which was attributed to overall siphon color and/or chloroplast pigmentation. These characters and measurements suggest affinity with the description of Avrainvillea erecta (Berkeley) A. Gepp & E.S. Gepp and their further morphological characterization by Olsen-Stojkovich (1985).

Molecular assessment

The majority of examined specimens were sequenced for both rbcL and tufA, however, molecular characterization of historical material was only successful for rbcL for one of the heterotypic synonym type specimens - Chloroplegma papuanum BM000561613. The concatenated alignment of the two gene regions yielded a dataset of 1,360 bp. Both the Maximum Likelihood and Bayesian inference phylogenetic reconstructions strongly supported that the newly recorded Avrainvillea species, A. cf. erecta , was clearly distinct from Hawai‘i specimens identified as " A. amadelpha " ( Brostoff 1989); these newly sequenced specimens belong to the " obscura " group while " A. amadelpha " clusters within the “longicaulis” group ( Olsen-Stojkovich 1985) (Fig. 3). These analyses also support the monophyletic grouping of sequences from the newly sequenced specimens and those morphologically identified as A. cf. erecta (Berkeley) A. Gepp & E. S. Gepp from Japan and Micronesia. Although they exhibited two different morphs (loose siphons or blade), all specimens from the two Hawai‘i populations had identical DNA sequences.