Mark J. Grygier

New records, external and internal anatomy, and systematic position of Hansen's y-larvae (Crustacea: Maxillopoda: Facetotecta)

Abstract Y-larvae comprise the crustacean taxon Facetotecta. A new kind of ‘nauplius y’, designated Type VI, is described from plankton in Disko Bay. West Greenland. The internal anatomy and some external features of ‘cypris y’ are described from a 2 μm-sectioned specimen collected in Oresund and from a whole-mounted specimen from Disko Bay. Newly discovered or reinterpreted features of ‘cypris y’ include: sessile compound eyes with tripartite crystalline cones; two pairs of eye-associated sensory organs which are homologized with the biramous, plumose cephalic organs found in some Ascothoracida; the antennular segmentation; identification of the ‘oral pyramid’ as the labrum with a posterior mouth and blind pharynx; sparse cephalic musculature except in antennules; first thoracic tergite shared by first two thoracomeres (first thoracomere not fused to head); a complicated array of basal thoracopodal sclerites; a solid oesophagus trace and no differentiated midgut (dorsal yolk or oil globules instead); a c...

Nauplii, Antennular Ontogeny, and the Position of the Ascothoracida within the Maxillopoda

ABSTRACT The external anatomy of over 25 species of ascothoracid nauplii, and the later ontogeny of their antennules, are reviewed and compared to other maxillopodan subclasses. The brooded nauplii are of the nonbranchiopod type. Although lacking frontolateral horns, generalized ascothoracid nauplii (Lauridae, Petrarcidae, Synagoga) are most similar to early instar cirriped nauplii, but many of the features in common are probably symplesiomorphies. Ascothoracids and cirripeds may have a common basic naupliar ontogeny, but features of later cirriped instars, many of which are associated with feeding, are delayed or entirely suppressed in ascothoracids due to brooding. A planktonic metanauplius from the South China Sea that combines ascothoracid features with late cirriped naupliar limbs is tentatively identified as a postbrooding ascothoracid, perhaps of the Lauridae. Lack of postmaxillular limb buds in metanauplii is a possible synapomorphy of the Ascothoracida, Cirripedia, and Facetotecta (Hansens y-larvae). The 6 apparent segments in a generalized ascothoracid naupliar antennule are not the same as the 6 in the adults. The 3 distal segments fuse (the adults movable claw does not represent a segment) and 2 new segments appear basally, so that there are 8 segments altogether in ontogeny. Eight-segmented antennules are proposed as a new diagnostic feature of the Maxillopoda. The positional homology of the ascothoracid claw and the cirriped cyprid attachment disc is shown by following supposedly homologous setae in the nauplii through later development. The antennular claws of cypris y and of branchiurans may also be of similar origin. These findings, together with other published data, tend to contradict a spermatology-based phylogeny of the Maxillopoda, but do not wholly resolve the AscothoracidaCirripedia relationship.

Microdajus (Crustacea: Tantulocarida) parasitic on an Antarctic tanaidacean, and a range extension of M. langi Greve

Ectoparasitic tantulocaridan crustaceans, Microdajus aporosus sp. nov., were found attached to the tanaidacean crustacean Meromonakantha macrocephala (Hansen) from 568 m in the Ross Sea. A single host bore on its pereiopods five expanded tantulus larvae with gestating males and two isolated cephalons of the parasite. Microdajus langi Greve is newly reported from the Gullmarfjord, Sweden. A recent comparison of tantulocaridan thoracopods to maxillopodan naupliar appendages is evaluated in the light of recent morphological and ontogenetic findings.

Gorgonolaureus muzikae sp. nov. (Crustacea: Ascothoracida) parasitic on a Hawaiian gorgonian, with special reference to its protandric hermaphroditism

Summary Twenty-five specimens of a new ascothoracid parasite, Gorgonolaureus muzikae were found within cortical galls on specimens of a bathyal Hawaiian gorgonian, Placogorgia sp. These represent the first ascothoracid known from Hawaii. G. muzikae differs from its congener G. bikiniensis primarily in its larger size and details of setation. Five developmental stages are described and illustrated: the mature female, young female, late protander, protander, and nauplius. The protander is compared to species of Synagoga, and the characters distinguishing the two genera are specified. Sexuality in Ascothoracida is reviewed, and the life cycle of G. muzikae is reconstructed as follows: eggs and larvae are brooded within the carapace of a mature female; a bivalved, free-swimming male stage is postulated; after inseminating one or more established females it settles permanently on a host gorgonian; as the protandric male changes into a female, the carapace valves fuse and expand dorsally, the first and second a...

Revision of Synagoga (Crustacea: Maxillopoda: Ascothoracida)

Summary This paper is a revision of the most primitive genus of the Ascothoracida, Synagoga Norman. The three previously described species, S. mira Norman, 1888 (the type), S. metacrinocola Okada, 1926, and W. sandersi Newman, 1974, are partly redescribed to correct errors and to add new details. A new genus, Waginella gen. nov., is proposed for the latter two species, and the diagnosis of Synagoga is restricted. Synagoga normani sp. nov. lives on the soft coral Dendronephthya sp. in shallow water near Mombasa, Kenya. It is larger than S, mira and its appendages differ in minor respects. New specimens of W. metacrinicola and W. sandersi from their respective type localities were examined. The major features of S. sandersis internal anatomy are similar to W. metacrinicola (Okada 1926). Crinoids from S. sandersis type locality showed no evidence of ascothoracid infestation. The new specimens of W. sandersi were infested with cryptoniscid isopods; a questionable record of the same isopod species suggests t...

An ascothoracid compound eye (Crustacea)

The ultrastructure of the compound eye of an ascothoracid larva — the only known occurrence of compound eyes in the Ascothoracida — is described. The ommatidia of apposition type consist of a crystalline cone composed of three cells and up to six retinular cells. Poor fixation of the scarce material allows no safe judgement about the number of retinular cells and the nature of two distal cells surrounding the crystalline cones. The structure of these compound eyes most closely resembles the cirriped compound eye.

A new species of Schizopera (Copepoda: Harpacticoida) from Japan, its phylogeny based on the mtCOI gene and comments on the genus Schizoperopsis

The predominantly marine genus Schizopera Sars, 1905 has only two significant inland water species-flocks, one in the ancient African Lake Tanganyika and the other in subterranean waters of Western Australia. Discovery of Schizopera abei sp. nov. from several interstitial locations in the vicinity of the ancient Lake Biwa has wider implications for the study of morphological homoplasies in the genus, as well as for the study of freshwater invasions in harpacticoid copepods. The new Schizopera species belongs to a small group of congeners with a two-segmented endopod of the fourth leg, which used to be recognised as a separate genus, Schizoperopsis Apostolov, 1982. Our reconstructed phylogenies based on the mtCOI partial sequences suggest that this character probably evolved convergently in at least some Schizopera, thus rendering the genus Schizoperopsis polyphyletic. However, almost all basal nodes in our cladograms are weakly supported, which shows limitations of a single-gene approach for reconstructing phylogenetic relationships. The new species is the first member of its genus from Japanese inland waters, and it has no close relatives among extent congeners anywhere in the world. We speculate that its ancestor may have invaded Lake Biwa, and subsequently its surrounding subterranean waters, from brackish areas around central Japan, presumably during a period of high sea water level through its major outflow river. This discovery may provide further support for the hypothesis about the role of ancient lakes as biodiversity pumps for subterranean habitats. http://zoobank.org/urn:lsid:zoobank.org:pub:1F71F7AD-B7C8-4AD3-BE44-5E1BEE4E2AA8

New ascothoracid crustacean endoparasites of Scleractinia

The ascothoracid crustacean genus Petrarca, endoparasites of scleractinian corals, is reviewed and revised. Petrarca bathyactidis, the type-species, is partly redescribed. The range of P. okadai is extended to East Africa. Three new species of Petrarca are described: P. indica in Flabellum deludens from the Indian Ocean near Ceylon; P. morula from Turbinaria sp. in the Banda Sea; P. azorica in Enallopsammia rostrata from the North Atlantic. Zibrowia auriculata gen. et sp. nov. infests Balanophyllia carinata off East Africa, and the same species appears to live in Tubastraea micranthus off East Africa and Dendrophyllia sp. at Reunion and in the Comoros. Unlike other ascothoracids, eggs and larvae are not brooded within the carapace valves, though they may be attached to them externally. Nauplii of P. okadai and Z. auriculata are described; they are generalized with familially distinct features. Adults of both genera have an overall neotenic appearance. They always occur in galls in groups of two or more, s...

Morphology and systematic significance of the mystax, a hitherto undescribed cephalic structure of males in certain Notostraca (Branchiopoda)

Abstract We report on the morphology and occurrence of the “mystax,” an overlooked cephalic structure found in males of certain Notostraca. The mystax is a conspicuous, protuberant, dark-brownish sclerodermal stripe located on the anteroventral flange of the carapace. Histological sections show the mystax as an expansion of the exoskeleton formed by the exocuticle. Examination of exuviae revealed that the old mystax remains intact in the shed cuticle. In some Triops populations of México and Japan, large individuals bearing ovisacs exhibit a “pseudomystax,” which consists of a dark-brownish band in nearly the same position as the mystax, but it does not form a protuberant stripe. A total of 661 males and 6402 ovisac-bearing individuals from four continents were examined. The mystax was found in males of Triops australiensis from Australia, T. granarius from Japan, Triops sp. from North America, Triops sp. from Africa, and Triops sp. from Asia. The mystax is absent in all ovisac-bearing individuals of all species analyzed and in all males of Triops cancriformis (Africa, Europe, and Japan), and in all males of the genus Lepidurus. Practical and systematic implications of the mystax are discussed.

Cryptoniscidae s.s. (Isopoda : Epicaridea) : Nomenclatural History and Recommendations

The nomenclatural history of the parasitic isopod family Cryptoniscidac Kossmann, 1880 sensu stricto is reviewed, and irregularities are exposed and corrected. Eumetor Kossmann, 1872 and its type species E. liriopides Kossmann, 1872 are available but unrecognizable except by host. Cryptoniscus curuatus fraisse, 1877 is designated here as the type species of Danalia Giard, 1887. Danalia lobiancoi Giard & Bonnier, 1890 is a nomen nudum since it was merely mentioned in a list with its host. At least five of the 12-13 available nominal species currently assigned to Danalia are nearly unrecognizable except by host. Neither Zeuxokoma Zimmer, 1927 nor Zeuxokoma Neave, 1940 qualifies as an available replacement name for the preoccupied Zeuxo Kossmann, 1872 because of lack of reference to the earlier name and lack of a type species designation, respectively. Zeuxokoma nom. nov. is proposed here as a replacement name for Zeuxo Kossmann, and Zeuxo alplzei Kossmann, 1872 is designated here as the type species. The nominal subfamily Fabinae Danforth, 1970 (1963?) is unavailable because neither work involved was published in the sense of the International Code of Zoological Nomenclature. The nominal family Danaliidae Altes, 1982 includes Cryptoniscus Miiller, 1864, and is thus a junior synonym of Cryptoniscidae Kossmann, 1880.