4.2 | The Lobata
When the COI phylogeny was limited to the lobate ctenophores, which form a monophyletic clade (including Thalassocalyce and Cestids; Podar, 2001), phylogenetic resolution was improved, and theCOI fragment revealed that many genera were polyphyletic (Figure 4b). One example; tropical species of Bolinopsis mikado (Japan),B. vitrea (Bahamas), B. aff. vitrea (Hawaii) andB. ashleyi (Australia) all formed a well-supported clade withMnemiopsis leidyi. The temperate species Bolinopsis infundibulum (Atlantic Ocean) and a new Bolinopsis MOTU from the eastern Pacific were in a distinct and well-supported clade (Figure 4b; and Johnson et al. in prep). This was in contrast to the18S fragment where species within Bolinopsis genus were undifferentiated, with the exception of a few individuals of B.aff. vitrea collected near Hawaii and Moorea (Figure 4a). Clearly, more data from more localities, along with transcriptomes and genomes, are critical in understanding relationships among ctenophores, but the COI gene provides a useful starting point.
4.3 | Morphological and molecular concordance
Mitochondrial sequencing reinforced the designation of several undescribed species that returned one 18S MOTU, but differed morphologically or ecologically (Figure 4). Lampocteis cruentiventer (Figure 5a) and Lampocteis ‘sp. V’ (Figure 5b), differed by ~10% GTR distance and were segregated by depth. A third suspected species within the genus was Lampocteis‘sp. A,’ (Figure 5c) which are typically amber rather than a brilliant red color, although color is often a misleading trait. However,COI sequences for Lampocteis ‘sp. A,’ differed from the other two MOTUs by ~17% GTR distance, which gave strong support for a distinct species.
The COI fragment revealed three distinct Bathocyroe MOTUs collected from California, and one from the Gulf of California, Mexico, in contrast to the single MOTU that was returned by the 18Sfragment (Figs. 4a, b, 5d–f). There are three described species within the genus including B. fosteri (Madin & Harbison 1978) from the Gulf of Mexico, B. paragaster (Ralph & Kaberry 1950) from the South Western Pacific, and B. longigula (Horita et al. 2011) from shallow waters in Japan. Bathocyroe aff. fosteri ‘A’ collected from California most closely matched the description ofB. fosteri (Figure 5d). Bathocyroe aff.longigula (Figure 5f) from California resembled B. longigula somewhat, in having an elongated stomodaeum, but it lacked any colored spots along the meridional canals and the gut appeared wider than that of B. longigula . In addition, theB. aff. longigula from California was mainly found from ~2000–3000 meters depth and B. longigula in Japan was collected at the surface (although deep species are known to be occasionally upwelled to the surface in those waters.). In California, B. aff. longigula and B. aff.fosteri ‘ A’ had overlapping depth ranges, distributions, but had small distinctions in gut shape (Figure 5d, f) and were the most divergent from one another molecularly (15% GTR). The third MOTU from California, Bathocyroe aff. fosteri ‘B’, had a distinct gut shape and color from all the other MOTUs, was relatively rare, and was only collected below 3000 meters depth (Figure 5e). Unfortunately, specimens from type localities were unavailable for sequencing so it is unclear if any of the MOTUs we sequenced match those already described or new to science. However, with our new primers researchers world-wide can now amplify species of Bathocyroe and help to confirm species identifications.
The COI fragment sequences also resolved the relationships between Deiopea kaloktenota (Chun 1880) andKiyohimea usagi (Matsumoto & Robison 1992). It was first suspected that despite morphological distinctions, Deiopea might be a juvenile form of Kiyohimea (Matsumoto & Robison 1992). By sequencing the COI fragment we found two distinct lineages ofDeiopea from California in addition to that of K. usagi. A single specimen collected offshore of the Hawaiian Islands also was the same MOTU as one of the Deiopea from California, showing this species has high dispersal capabilities and a broad oceanic distribution. Specimens of D. kaloktenota, which were described from the N. Atlantic, and K. aurita (Komai & Tokioka 1940) from Japan were unavailable for sequencing, so it is unclear whether one or both species of Deiopea from Monterey Bay are undescribed.