On Sea Turtle‐associated Craspedostauros (Bacillariophyta), with Description of Three Novel Species

Abstract

The current study focuses on four species from the primarily marine diatom genus Craspedostauros that were observed growing attached to numerous sea turtles and sea turtle‐associated barnacles from Croatia and South Africa. Three of the examined taxa, C. danayanus sp. nov., C. legouvelloanus sp. nov., and C. macewanii sp. nov., are described based on morphological and, whenever possible, molecular characteristics. The new taxa exhibit characters not previously observed in other members of the genus, such as the presence of more than two rows of cribrate areolae on the girdle bands, shallow perforated septa, and a complete reduction of the stauros. The fourth species, C. alatus, itself recently described from museum sea turtle specimens, is reported for the first time from loggerhead sea turtles rescued in Europe. A 3‐gene phylogenetic analysis including DNA sequence data for three sea turtle‐associated Craspedostauros species and other marine and epizoic diatom taxa indicated that Craspedostauros is monophyletic and sister to Achnanthes. This study, being based on a large number of samples and animal specimens analyzed and using different preservation and processing methods, provides new insights into the ecology and biogeography of the genus and sheds light on the level of intimacy and permanency in the host–epibiont interaction within the epizoic Craspedostauros species.

Cultivating epizoic diatoms provides insights into the evolution and ecology of both epibionts and hosts

“…POE taxa were identified based on the available literature and included diatom species that have only ever been observed in association with the epizoic habit being found on multiple animal specimens 6 , 8 , 10 , 11 , 14 – 16 , 24 , 25 , 30 . Among these were epizoic taxa typically reaching high relative abundances (> 25%)— Achnanthes elongata Majewska & Van de Vijver, Chelonicola costaricensis Majewska, De Stefano & Van de Vijver, C. caribeana Riaux-Gobin, Witkowski, Ector & Chevallier, Craspedostauros danayanus Majewska & Ashworth, Medlinella amphoroidea Frankovich, Ashworth & M.J.Sullivan, Poulinea lepidochelicola Majewska, De Stefano & Van de Vijver, Tursiocola spp., as well as species often present on animals but never exceeding 10% of the diatom relative abundance— Craspedostauros alatus Majewska & Ashworth, C. macewanii Majewska & Ashworth, Proschkinia sulcata Majewska, Van de Vijver & Bosak and P. vergostriata Frankovich, Ashworth & M.J Sullivan.…”

Culturing Putatively Obligate Epizoic Diatoms: Insights For The Evolution And Ecology Of Diatoms And Their Host

“…loggerheads; [21]). The opposite phenomenon could explain low epizoic diatom diversity on leatherback sea turtles [5,30], and pelagic sea snakes [23] that spend signi cant (though not exclusively [56] time feeding in the pelagic zone rather than on benthic organisms [57]. This follows the general pattern of low macro-epibiotic diversity on leatherbacks [58].…”

A New Insight Into Amicula, a Genus of Tiny Marine Benthic Diatoms With the Description of Two New Tropical Species and the Largest Mitogenome Known for a Stramenopile

“…8.2.7 (Stamatakis, 2014) software package. Alignments and analytical parameters followed those described in Majewska et al (2021). One used a 3-gene dataset (SSU-rbcL-psbC) as in Majewska et al (2021) and the other a 7-gene dataset (SSU-rbcL-psbC-psaA-psaB-psbA-atpB) as in Theriot et al (2015).…”

“…Alignments and analytical parameters followed those described in Majewska et al (2021). One used a 3-gene dataset (SSU-rbcL-psbC) as in Majewska et al (2021) and the other a 7-gene dataset (SSU-rbcL-psbC-psaA-psaB-psbA-atpB) as in Theriot et al (2015). The 3-gene dataset included both A. micronesica and A. vermiculata, while the 7-gene dataset included only A. micronesica, as solely the rbcL sequence was available for A. vermiculata.…”