Jonathan WrightHundreds of fascinating jellyfish-like creatures wash up on Cornwall beach
Dezene Huber π»One of the best uses of #DNA 𧬠#barcoding is linking different life stages of single #species that appear different from each other and do different things.
In this paper the authors used barcoding to figure out which #polyp (sedentary) and #medusa (swimming) life stages of several #hydrozoans (related to #sea #jellies and sea #anemones) belong to each other.
π: https://peerj.com/articles/15118/
Title: Odd family reunion: DNA barcoding reveals unexpected relationship between three hydrozoan species
Odd family reunion: DNA barcoding reveals unexpected relationship between three hydrozoan species
Knowledge of life histories is crucial for understanding ecological and evolutionary processes, but for many hydrozoan species only incomplete life cycles have been described due to challenges in linking hydromedusae with their polyp stages. Using a combination of DNA barcoding, morphology, and ecological information, we describe for the first time the polyp stage of Halopsis ocellata Agassiz, 1865 and re-describe that of Mitrocomella polydiademata (Romanes, 1876). Campanulinid hydroids referable to Lafoeina tenuis Sars, 1874 and collected in the same biogeographic region as the type locality of this species are shown to be the polyp stage of these two mitrocomid hydromedusae. The nominal species L. tenuis thus is a species complex that includes the polyp stage of medusae belonging to at least two genera currently placed in a different family. Consistent morphological and ecological differences were found between the polyps linked to each of these two hydromedusae, but molecular results suggest that yet other species may have morphologically similar hydroids. Polyps morphologically identified to L. tenuis are therefore better referred to as Lafoeina tenuis-type until further associations are resolved, particularly when occurring outside of the area of distribution of H. ocellata and M. polydiademata. Molecular identification integrated with traditional taxonomy is confirmed as an effective approach to link inconspicuous stages of marine invertebrates with hitherto unknown life cycles, especially in often-overlooked taxa. Disentangling the relationships between L. tenuis, H. ocellata, and M. polydiademata lays the ground for future research aimed at resolving the taxonomy and systematics of the enigmatic families Mitrocomidae and Campanulinidae.
Peter Barnes#Dogwalking miscellany
A blue, #beachcombing edition.
The first image is the beautiful radial skeleton of the Blue Button, or Porpita porpita, a colony organism (when alive), made up of cooperating hydroids. It drifts in the surface waters, using its stinging tentacles to capture small copepods, but will also hunt crabs and fish.
Next is the bluebottle, Physalia utricula, well known on Australian beaches. It's also a colony organism with stinging tentacles.
The next two are mollusks, one with and one without a shell, both preying on the former pair.
The first is the beautiful violet sea snail, Janthina janthina, a free-floating mollusk that uses a raft of bubbles to keep it on the surface where it preys on hydrozoa. (unlike the others, this was taken back home with my D700, not the iPhone3GS).
The second is the spectacular nudibranch Glaucus atlanticus, Sea swallow or Sea dragon. This predator cunningly saves and stores the nematocysts, or stinging barbs, from its prey and uses them to defend itself, so picking one up with bare hands can result in a stings just as painful as a bluebottle.
Unfortunately this last picture is very poor quality, being made in a hurry with an iPhone 3GS, and with the animal out of the water so that its branching arms are collapsed.
#beachcombing
#photography #beach #macro #animals #iphoneography #iphone3gs #nikon