Morphology, ecology, and molecular biology of a new species of giant larvacean in the eastern North Pacific: Bathochordaeus mcnutti sp. nov.

Abstract

Bathochordaeus mcnutti sp. nov. is described from the mesopelagic northeast Pacific Ocean (Monterey Bay, California, USA). Larvaceans in the genus Bathochordaeus are large, often abundant zooplankters found throughout much of the world ocean, but until recently it was unclear whether more than a single species of Bathochordaeus existed. Using remotely operated vehicles, we have made hundreds of in situ observations, compiled two decades of time-series data, and carefully collected enough specimens to determine that three species of Bathochordaeus occur in Monterey Bay: B. charon (Chun), B. stygius (Garstang), and B. mcnutti sp. nov. Bathochordaeus mcnutti is readily distinguished from its two congeners by the distinct blue outline visible around the periphery of its tail, and by other aspects of its morphology, ecology, and genetics. The abundance of larvaceans means they are ecologically important as particle processors. Species within the genus, Bathochordaeus, comprise the largest of described larvaceans.Electronic supplementary materialThe online version of this article (doi:10.1007/s00227-016-3046-0) contains supplementary material, which is available to authorized users.

Genomic evidence of recent hybridization between sea turtles at Abrolhos Archipelago and its association to low reproductive output

“…Backcrossed hatchlings have also been reported, confirming that F1 hybrids are fertile and introgression may be possible 10 , 13 . Despite the confirmed viability of hybrid F1 females, it has been shown that their nests in northern Bahia have a lower success rate of hatching emergence, whilst other reproductive output parameters, such as hatchling production per clutch, clutch frequency and breeding frequency remained similar to the parental species 14 . Furthermore, no negative effect of hybridization was found on hatchling viability 15 .…”

The Coevolution of Midwater Research and ROV Technology at MBARI

“…For both of these "new" animals, it is the detailed video footage, deposited along with the type "specimens, " that provides the vouchers for verification. For large larvacean species, the external feeding filters can be critical criteria for characterization, but these structures are likewise so delicate that they can only be described from in situ observations (Hamner and Robison, 1992;Hopcroft and Robison, 1999;Sherlock et al, 2017).…”

Widespread use of the “ascidian” mitochondrial genetic code in tunicates

“…We used the consensus of the published B. stygius Cox1 sequences KX599267.1 to KX599281.1 from GenBank (Sherlock et al, 2017), to screen the genome and scaffold SCLE01415711.1 (length 10,388 nt) gave a perfect hit. We translated Cox1 from position 8054 to 6522 on the reverse strand, and a partial Cob sequence from scaffold SCLE01415711.1 (2319 to 2963, reverse strand).…”

“…Sakaguchi et al (2017) reported that all Oikopleura dioica mitochondrial sequences (AY116609-AY116611 and KF977307) may be contaminations from bacteria or cnidarians, and provided partial sequences for Oikopleura longicauda in the same study. Partial mitochondrial sequences were published for Bathochordaeus and Mesochordaeus species by Sherlock et al (2017). In addition, Naville et al (2019) recently published draft genome for several appendicularian species.…”