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AnimaliaacceptedgenusAccepted
Didemnum

Didemnum

Savigny, 1816

GBIF:159167981

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Descriptions(1)

Figure 5 F, G IHAK 31 BHAK 1692. Triquet Island Macro site, Scuba, 8 m. On boulder. IHAK 42 BHAK 1709. Starfish Rocky Reef Site, Scuba, 18 m, rock outcrop. Very dense superficial spicule layer, none in middle region of tunic and at most a thin spicule layer in basal region. Spicules small, stellate with short but sharply pointed rays. Zooids bright yellow-orange. Six very sharply pointed lobes on oral siphon, long muscular process extending into tunic from base of thorax. Single testis, about seven turns of the sperm duct but it was not possible to count accurately. No larvae were observed. This species may be D. carnulentum Ritter & Forsyth, 1917, but additional work is required to determine whether this is an already named or new species.
Lambert, Gretchen (2019): The Ascidiacea collected during the 2017 British Columbia Hakai MarineGEO BioBlitz. Zootaxa 4657 (3): 401-436, DOI: 10.11646/zootaxa.4657.3.1

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CLASSIFICATION

Taxonomic Classification Tree

AnimaliaChordataAscidiaceaEnterogonaDidemnidaeDidemnum

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Media Files(1)

FIGURE 5. Didemnidae. A–E: Didemnum sp. 1, undescribed species. A: whole colony on kelp holdfast. B: detail of tunic surface showing one cloacal opening. C: bifurcated testis from a zooid showing numerous coils of the sperm duct; D: tunic spicules. E: two cryptically colored lamellarid nudibranchs above a colony piece from which they were collected. F, G: Didemnum sp. 2. F: numerous small colonies or pieces of same colony; G: two cross sections of a different colony showing distribution of spicules. Scale bars: A, 1 cm; B, 1.5 mm; C, 0.1 mm; D, 20 µm; E, 1 cm.; F, 9 mm; G, 4 mm.

Imageimage/png© Lambert, GretchenLambert, Gretchen

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Source Information

The Ascidiacea collected during the 2017 British Columbia Hakai MarineGEO BioBlitz

checklist

This dataset contains the digitized treatments in Plazi based on the original journal article Lambert, Gretchen (2019): The Ascidiacea collected during the 2017 British Columbia Hakai MarineGEO BioBlitz. Zootaxa 4657 (3): 401-436, DOI: 10.11646/zootaxa.4657.3.1

Abstract

A three-week intensive marine biodiversity survey was carried out at a small remote region of the central British Columbia coast at and near the Calvert Island Marine Station (Hakai Institute) July 21–August 11, 2017. The survey included daily sampling by the staff and a number of visiting taxonomists with specialties covering all the major groups of invertebrates. Many marine habitats were sampled: rocky and sand/gravel intertidal and tidepools, eelgrass meadows, shallow and deeper subtidal by snorkel and Scuba, plus artificial surfaces including the sides and bottom of the large floating dock at the Institute and settlement plates set out up to a year previously at various subtidal sites. Many new species were recorded by all the taxonomists. In this very biodiverse remote area 36 ascidian species were identified: 18 Aplousobranchia, 7 Phlebobranchia, and 11 Stolidobranchia, comprising a total of 15 solitary and 21 colonial species including two undescribed colonial species. This represents almost one third of all the known North American species from Alaska to southern California in this limited very remote area. Remarkably, only two are possible non-natives. Diplosoma listerianum (Milne-Edwards, 1841), was collected mostly on natural substrates including deeper areas sampled by Scuba, and one colony occurred on a settlement plate. A few Ciona savignyi Herdman, 1882 were collected, two from natural substrates and four from artificial surfaces. There were no botryllids, Styela clava Herdman, 1881, Didemnum vexillum Kott, 2002, or Molgula manhattensis (De Kay, 1843), though these are all common and sometimes very abundant non-natives in other parts of BC and along much of the U.S. west coast. Most of the species encountered are known in northern California, Washington, and southern BC, but only a small number are represented among the few known Alaska species.

Lambert G, plazi (2019). The Ascidiacea collected during the 2017 British Columbia Hakai MarineGEO BioBlitz. Plazi.org taxonomic treatments database. Checklist dataset https://doi.org/10.11646/zootaxa.4657.3.1 accessed via GBIF.org on 2026-06-16.

CC0Published 8/20/2019View dataset
GBIF Usage Key
159167981
Dataset Key
3414318d-7570-49ac-9013-be4e1f1e6347
Origin
source
Backbone Key
2329630
Taxon ID
6A2E3761A93AFFCD1390FA74DD27F8F5.taxon
Last Crawled
6/10/2026
Last Interpreted
6/10/2026
View on GBIFSource Reference