Andrei V. Grischenko

Diversity and taxonomy of intertidal Bryozoa (Cheilostomata) at Akkeshi Bay, Hokkaido, Japan

We found 39 cheilostome species among more than 7000 specimens collected at 10 intertidal sites in rocky habitats along the shore of Akkeshi Bay, eastern Hokkaido Island, Japan. These species are herein described in detail and illustrated by scanning electron microscopy. Nine species (23% of total) are described as new (Electra asiatica, Callopora sarae, Conopeum nakanosum, Cauloramphus cryptoarmatus, Cauloramphus multispinosus, Cauloramphus niger, Stomachetosella decorata, Microporella luellae, and Celleporina minima), and 21 species (54%) are reported for the first time from Japan. Species richness ranged from eight to 29 species per study site. A TWINSPAN analysis showed the species fell into nine groups defined by the local pattern of distribution. A cluster analysis of study sites based on similarity of species composition showed three faunistic groups distributed geographically: in Akkeshi Lake, along the eastern‐central shore of the bay, and at the mouth of the bay. Species richness in estuarine Akkeshi Lake was low, with a species composition very different from the outer bay. Most cheilostomes were found on rock and shell substrata, but uncommonly occurred on concrete walls, algae, hydroids, tubes of polychaetes, other bryozoans, and anthropogenic debris. Of the 39 species found, 33 (85%) contained embryos during the collecting periods, 2–7 June and 3–6 July 2004. The biogeographical composition of intertidal cheilostomes at Akkeshi Bay included species with Arctic‐Boreal (28%), Boreal (59%), and Boreal‐Subtropical (13%) distributions. The overall species richness of intertidal cheilostomes was two‐thirds that documented intertidally in a comparable study at Kodiak, Alaska, a locality 15° higher in latitude. We attribute the lower richness at Akkeshi to differences in the nearshore marine environment between the two localities.

A New Cheilostome Bryozoan with Gigantic Zooids from the North-West Pacific

Abstract Gontarella gigantea gen. et sp. nov. is described from two stations, one in the Sea of Okhotsk and the second on the Pacific side of the Small Kuril Arc. This membraniporiform anascan cheilostome bryozoan has very large zooids, the largest known among extant sheet-like encrusting anascans. Comparative data on similar sheet-like cheilostomes gathered from the literature shows that the new species represents a conspicuous outlier in size, with the surface area of the zooid being approximately twice that of the next largest species. Skeletal evidence, including the lack of ovicells, indicates that G. gigantea belongs within the malacostegan family Electridae. The gigantic ancestrula suggests that the species has a cyphonautes larva about 1 mm in maximum dimension.

Cribrimorph and Other Cauloramphus Species (Bryozoa: Cheilostomata) from the Northwestern Pacific

We provide original descriptions for nine new species in the cheilostome bryozoan genus Cauloramphus (C. gracilis, C. Ordinarius, C. amphidisjunctus, C. cheliferoides, C. oshurkovi, C. infensus, C. parvus, C. peltatus, and C. ascofer) and a redescription of C. disjunctus Canu and Bassler, 1929. We delineate a group of eight species, here termed the ‘C. disjunctus clade,’ that have the opesial spine joints calcified to a greater or lesser extent in mature zooids; most also have paired, hypertrophied avicularia. This group includes C. amphidisjunctus, C. cheliferoides, C. infensus, C. parvus, C. peltatus, and C. ascofer in the Aleutian Islands, Alaska; C. oshurkovi in the Commander Islands; and C. disjunctus in Japan. High levels of apparent endemism in two unrelated bryozoan genera (Cauloramphus and Monoporella), and geographical population differentiation in C. ascofer indicating ongoing allopatric speciation, suggest high speciation rates for deep benthic bryozoans in the western Aleutians. A phylogenetic hypothesis for the C. disjunctus clade indicates that populations of Cauloramphus dispersed between the Aleutians and Asia on at least three separate occasions, and that the polarity of at least two of these dispersal events was from the Aleutians to Asia.

Doryporella smirnovi sp. nov. (Bryozoa: Cheilostomata) and its impact on phylogeny and classification.

Abstract A new species of Doryporella, D. smirnovi sp. nov. is described from the area of the Commander Islands. Inclusion of this species in a revised phylogenetic analysis of Doryporella and its relatives permits the recognition of a clade comprising Doryporella and Doryporellina. This clade is accorded family-level status as the Doryporellidae fam. nov., thereby removing Doryporella (and Doryporellina) from the large and paraphyletic Calloporidae.

Rocky-intertidal cheilostome bryozoans from the vicinity of the Sesoko Biological Station, west-central Okinawa, Japan

ABSTRACT To complement previous studies on the diversity of cheilostome bryozoans (Bryozoa: Gymnolaemata: Cheilostomata) in the rocky-intertidal habitat in the North Pacific, we sampled rocky substrata at three sites on the subtropical East China Sea coast of Okinawa, Japan (26°N). We examined 651 colonies or colony fragments by light microscopy or scanning electron microscopy (SEM). The range in single-site richness was 16–36 species, with 52 species detected overall. We provide descriptions and illustrations for all species, including 11 (21.2%) new species (Thalamoporella karesansui, Crassimarginatella eremitica, Hippothoa petrophila, Stephanotheca fenestricella, Calyptotheca sesokoensis, Fenestrulina parviporus, Arthropoma harmelini, Rhynchozoon maculosum, Rhynchozoon lunifrons, Rhynchozoon ryukyuense, and Rhynchozoon scimitar) and 34 (65.4%) new records for Japan. Species were patchy in local distribution, with 53.8% detected at only one among the three sites, and often rare, with 34.6% represented by only one or two specimens. Most species (94.2%) were encrusting, forming two-dimensional, sheet-like colonies or (in two cases) branching uniserial networks; three species formed small, recumbent colonies. Ascophoran-grade species (82.7%) outnumbered anascan-grade species (17.3%). Biogeographically the fauna we examined is characteristic of the Central Indo-Pacific (CIP) realm of Spalding et al.: among 40 previously described species with distributions known outside the study area, 36 (90.0%) occur in the CIP realm, and 11 (27.5%) are restricted to it. In contrast, only seven species (17.5%) have been reported from the Temperate Northern Pacific realm, including two putatively cosmopolitan species. The high proportion (86.5%) of new records for Japan (including the new species) suggests that the marine bryozoan fauna in far-southern Japan remains largely unexplored. Given that many species were rare or uncommon in the study area and/or patchily distributed among the three sites, further sampling at additional intertidal sites in the Sesoko area will likely detect higher total local richness than the 52 species we found. http://www.zoobank/urn:lsid:zoobank.org:pub:9FD78C14-60AA-44A9-A9A2-3258E5770D31

Bryozoa (Cyclostomata and Ctenostomata) from polymetallic nodules in the Russian exploration area, Clarion–Clipperton Fracture Zone, eastern Pacific Ocean—taxon novelty and implications of mining

This work describes Bryozoa of the orders Cyclostomata and Ctenostomata found associated with polymetallic nodules collected by box-coring in the eastern part of the Russian exploration area of the Clarion-Clipperton Fracture Zone (CCFZ) under contract to Yuzhmorgeologiya. Scanning electron microscopic study of 358 cyclostome colonies and 14 ctenostome colonies from 4510-5280 m depth has resulted in the recognition of two new species of Ctenostomata, and 14 new species, nine new genera and two new families of Cyclostomata; three additional species of Cyclostomata are left in open nomenclature pending the discovery of missing reproductive characters. The taxonomic novelty is thus notable. One of the new Ctenostomata represents the first living example of the previously monotypic Late Cretaceous genus Pierrella. Twelve of the new cyclostome taxa have well-developed gonozooids, indicating that embryonic cloning (polyembryony) is normal in this deep-sea environment. On the other hand, one indeterminate tubuliporine and two rectangulates have dimorphic peristomes. In the latter two cases, enough mature colonies were found to suggest that this feature is normal, and that the dimorphic zooids are possibly female-in other words, capacious incubation chambers are apparently lacking, and therefore polyembryony would also be lacking or reduced. In one of these species, evidence is presented to suggest that the ancestrular zooid can reproduce precociously. Of the species reported here, only one has previously been found outside the exploration area, highlighting both the limited knowledge we have of bryozoans in the deep Pacific and/or a fauna that is largely endemic to the nodule environment. An additional 31 species of Cheilostomata have also been discovered that will be described in a subsequent publication. Most bryozoans are macrofaunal-sized, so are both inadequately determinable and overlooked in images obtained by remotely operated vehicles; yet, with 50 species, Bryozoa is the most speciose sessile macrofaunal phylum on the nodules. Nodules constitute hard substrata in an area otherwise mostly inhospitable for Bryozoa, hence mining would lead to loss of critical habitat. Further, as suspension-feeders, bryozoans are highly susceptible to smothering by suspended sediment, and non-mined areas closely adjacent to extraction zones would likely also be affected and their associated bryozoan fauna obliterated. More data are required on the distribution of the CCFZ bryozoan species elsewhere in the east Central Pacific to determine if mining would lead to local taxon extirpation or global extinction at both low and high taxonomic levels.

Figure 32. Calyssopora Vasiformis N. Gen., N In Bryozoa (Cyclostomata And Ctenostomata) From Polymetallic Nodules In The Russian Exploration Area, Clarion - Clipperton Fracture Zone, Eastern Pacific Ocean-Taxon Novelty And Implications Of Mining

FIGURE 44. Rallocytus ridiculus n. gen., n. sp. Progressive stages of development of ancestrulate colonies. A–D, specimen YMG4–14, Stn 340, at three-zooid stage, with no distinction among peristomes; E–H, specimen GLD4–09, Stn 183, with four functional zooids, one dimorphic; I–L, specimen GLD4–08, Stn 159, with six functional zooids, one dimorphic; M–P, specimen GLD4–11, Stn 206, five functional zooids, none dimorphic. Scale bars: A, E, 150 µm; B–D, F–P, 200 µm.

Systematics of some calloporid and lacernid Cheilostomata (Bryozoa) from coastal South Korean waters, with the description of new taxa

Six species in two families of Cheilostomata-Calloporidae and Lacernidae-are described from the southern coasts of the Korean Peninsula, resulting in a new distributional record and four new species to the Korean fauna. Further, Woosukia n. gen. is described, based on an existing species. Two species names (Crassimarginatella crassimarginata and Arthropoma cecilii) are deleted from the Korean faunal list owing to previous misidentification, with the net result that the Korean cheilostome fauna is increased to 125 species. The new additions to the fauna are: Crassimarginatella kumatae (Okada), Retevirgula asiana n. sp., Woosukia subhexagona (Ortmann), Arthropoma magniporosum n. sp., Arthropoma minus n. sp., and Phonicosia crena n. sp. The biogeographic relationships of some western Pacific taxa are discussed.

Intertidal Bryozoa from Korea—new additions to the fauna and a new genus of Bitectiporidae (Cheilostomata) from Baengnyeong Island, Yellow Sea

Eight species are added to the intertidal bryozoan fauna of South Korea, all collected from the extreme northwestern part of the country at Baengnyeong Island. Five of the species (Hippothoa imperforata, Celleporella hyalina, Celleporella nodasakae, Porella donoghueorum and Suhius rubescentis) are new records. Cauloramphus dicki n. sp., Cauloramphus spencerjonesae n. sp., and Exochella cryptodontia n. sp. are new to science; Suhius n. gen. is a newly recognized genus in Bitectiporidae. The close morphological similarity of umbonuloid-shielded P. donoghueorum to Australasian and Antarctic species of lepralioid-shielded species of Aimulosia is discussed in relation to ascophoran phylogeny. The described cheilostome fauna from South Korea is herein increased to 121 species.

Two new species of heavily calcified cyclostome bryozoans from the intertidal of Akkeshi Bay, Hokkaido, Japan

Cyclostome bryozoans are relatively uncommon in intertidal habitats, where they are subordinate to cheilostomes and ctenostomes. Those that do occur tend to have small colonies that are relatively weakly calcified. Here we describe two new species of intertidal cyclostomes from Akkeshi Bay in northern Japan that are unusual in having large, heavily calcified colonies. One of these – Favosipora ainui sp. nov. – is the first species of this genus recorded from Japan. The second species – Disporella ezoensis sp. nov. – although belonging to a genus well known from Japan and elsewhere globally, is unusual for Disporella in possessing colonies that are vivid red in colour. http://zoobank.org/urn:lsid:zoobank.org:pub:995903E6-9C07-436A-B788-29BDE2FD5A88