Biodiversity of bobtail squids from the Ryukyu Archipelago

Gustavo Sanchez^1*

¹Integrated Science for Life, Hiroshima University, Hiroshima, Japan

*corresponding author: moc.l1713554216iamg@171355421698s.z1713554216ehcna1713554216s.sug1713554216

Keywords: Bobtail squids; DNA barcoding; RNA sequencing; Taxonomy; Ryukyu Archipelago

Bobtail squids are small nektobenthic cephalopods inhabiting the Indo-Pacific Ocean, Atlantic Ocean, and the Mediterranean Sea. Some of these animals are emerging as model cephalopod species in different fields, yet their diversity has never been assessed.

The lack of morphological traits for species-level identification among bobtail squids has created several miss-assigned DNA barcodes in the database. In males, the shape of the hectocotylus (arm used for reproduction) is the main morphological trait for species-level assignment. At the same time, females lack clear traits for species-level assignment.

In this online forum, I will talk about our survey for bobtail squids in the Ryukyu Archipelago and how DNA barcoding, RNA-sequencing, and taxonomy help us describe three species, one of them a new species, the Brenner’s bobtail Euprymna brenneri. At the end of my talk, I will also introduce our upcoming work to study the evolution of these animals using genome skimming from specimens collected worldwide.

Interactive keys as a tool to assess biodiversity in selected deep-sea isopods

Karlotta Kürzel^1*, Anne-Nina Lörz¹, Ch. Oliver Coleman², Ralf Thiel¹, Stefanie Kaiser³, Saskia Brix⁴

¹Center of Natural History (CeNak), Universität Hamburg, Hamburg, Germany

²Museum of Natural History, Berlin, Germany

³University of Lodz, Łódź, Poland

⁴German Center for Marine Biodiversity (DZMB), Hamburg, Germany

*corresponding author: ed.xm1713554216g@lez1713554216reuk.1713554216attoL1713554216

Keywords: Taxonomic tools; Crustacea; Determination keys; Benthos; Biodiversity informatics

Interactive keys are a powerful to tool to assess biodiversity. If combined with illustrations of determination features and habitus even non-specialists can be guided through the determination process of different taxa. Here, the applicability of these interactive keys depending on current taxonomic knowledge was outlined by using selected isopod taxa (Crustacea) as an example.

Three interactive keys for different isopod taxa were created using the software DELTA (Descriptive Language for Taxonomists) as well as its module IntKey (Interactive Keys):

1. One generic key for the asellotan family Haploniscidae distributed around Iceland.
2. One species identification key for the haploniscid genus Haploniscus distributed around Iceland.
3. One species identification key for the desmosomatid genus Eugerdella distributed worldwide.

Digital illustrations were created for every determination feature, as well as for each habitus of each genus or species.

The applicability of the interactive keys strongly depends on the choice of distinguishing characters utilized as well as on the geographical area they were created for, and the percentage of undescribed species present there.

Diversification in a unique intertidal Mediterranean cryptobenthic fish genus

Maximilian Wagner^1,2*

¹Institute of Biology/Zoology, University of Graz, Graz, Austria

²Department of Biology, University of Antwerp, Antwerp, Belgium

*corresponding authors: ta.za1713554216rg-in1713554216u@ren1713554216gaw.n1713554216ailim1713554216ixam1713554216

Keywords: Cryptobenthic fishes; Mediterranean Sea; Clingfish; Gobiesocidae; Parallel evolution

Tiny cryptobenthic marine fishes are among the least studied vertebrates on this planet. However, they make up a remarkable biodiversity in the world’s oceans and are considered as key ecological components in near shore environments. Above all, they represent exciting models to study the diversification in marine environments. This is particularly true for the endemic clingfish genus Gouania, which, as the only vertebrate species in Europe, exclusively inhabits Mediterranean intertidal pebble beaches. An overall eel-like appearance as well as reduced fins and eye sizes can be considered as crucial adaptations to survive in these life hostile environments. Originally thought to be monotypic, a recent revision of the genus – based on morphological, biogeographic and genetic data – revealed a whole radiation of five highly divergent species that have evolved within the last five million years. Additionally, two very distinct morphotypes “slender” (higher number of vertebrae, small eyes) and “stout” (lower number of vertebrae, larger eyes), evolved independently in areas of sympatric occurrences (i.e., the Adriatic Sea and the eastern Mediterranean basin). Thus, these parallelly evolved morphotypes indicate niche partitioning as well as divergent selection to certain pebble beach microhabitats. Furthermore, on a microevolutionary scale, Gouania populations are highly structured and a strongly fragmented, which can be linked to a combination of low active dispersal ability as adults and a short pelagic larval phase. Whereas this might indicate even more undiscovered (genetic) diversity in Gouania in regions not yet studied, heavy tourist pressure and concomitant habitat alterations can be considered a major threat for vulnerable and isolated populations.

Racing extinction in the Mediterranean: Between climate and human impact

Manuel Marinelli^1*

¹Project Manaia, Spittal, Austria

*corresponding author: ta.ai1713554216anamt1713554216cejor1713554216p@leu1713554216nam1713554216

Keywords: Invasive Species; Habitat loss; Endangered species; Mass mortality; Mass extinction event

The Mediterranean is considered “Ground Zero” for global climate changes in marine ecosystems, and as such deserves additional attention. Project Manaia has been sailing and researching this unique marine ecosystem for 4 years now, documenting the observed changes in species composition, as well as changing habitats. In recent years, key ecosystems and breeding grounds were entirely lost within small time frames, putting a variety of species on the brink of extinction. While several marine species suffer from secondary endangerment, others are simply targeted by man: Overfishing, harvesting of coral, but also bycatch comes to mind and continues to have a massive impact on the existing ecosystems. In comparison, invasive species are a new occurrence to the Mediterranean Sea, but their occurrence is already starting to take its toll: By outrunning the local inhabitants when it comes to breeding rates, they take over entire regions within a single season, feeding on the local fauna and flora and pushing their prey into a threatened state within months. Other invaders move slowly but in masses: invasive Mnemiopsis has only been around for 5 years, but already threatens sardine populations in the entire Adriatic Sea – leaving even the humans without ideas as sardines are one of their key target species. We are “lucky” enough to live in an exceptional time of rapid change in ecosystems around the world. Now it is up to us to learn quickly enough to avoid rapid changes. For the first time in the history of this planet, we can witness changes to ecosystems within a single human life – a privilege we need to make the most of.

Invited panel members:

• Dr. Nancy Mercado Salas (Center of Natural History CeNak, Universität Hamburg, Germany)
• Thomas Luypaert (Tropical Ecology and Conservation, Norwegian University of Life Sciences, Ås, Norway)
• James Hagan (Department of Marine Science, University of Gothenburg, Sweden)
• Dr. Frederic Schedel (University of Basel, Switzerland)

All guests / listeners are very much welcome to discuss the talks and the broader topic. There will be no recording during the discussion.