Moonsnail hatching success, development timing and early feeding behaviour at the high-latitude White Sea

As predators, Naticidae (Gastropoda) can shape marine soft-sediment communities. Thus understanding of the reproductive biology and development of moonsnails is of great importance. Most moonsnails lay large egg masses, known as sand or egg collars, which are freely distributed on sand or muddy sediments. Here we report upon the abundance of egg collars of two naticid species, Amauropsis islandica and Euspira pallida, from the high-latitude White Sea, as well as describe the morphology of egg collars and hatching success, with a brief description of juvenile feeding in A. islandica. While in the subtidal zone, the egg collars of E. pallida were 10 times more abundant than of A. islandica, the egg collars of the latter species were the only ones that occur in the intertidal zone. The morphology of an egg collar of E. pallida differed from the literature descriptions by having a plicated basal margin. The number of egg capsules inside the collars was twice as high in A. islandica compared with E. pallida, but they were smaller. Amauropsis islandica hatchlings were larger and hatching success was more than twice that in E. pallida. We suggest that these characteristics promote the high abundance of A. islandica populations observed on some tidal flats of the White Sea. Surprisingly, A. islandica juveniles could perform non-drilling feeding in the first month after hatching. This study fills the gap in the knowledge of naticid reproductive biology at high latitudes.

Begonia depressinerva (sect. Baryandra, Begoniaceae), a new species from Luzon Island, the Philippines

A new peltate species of Begonia sect. Baryandra from Kidadayaig Falls, General Nakar, Quezon is described and illustrated here. The new species, B. depressinerva, is diagnosed against the morphologically similar B. tayabensis. The two species are similar by having rhizomatous stem, peltate, ovate leaf, and 5-tepalled pistillate flower, but the new species is remarkably different by having densely pilose, asymmetric leaf blade, densely pilose petiole that is inserted much closer to the basal margin, obtuse to subobtuse staminate flower outer tepal apex, and glandularly hairy ovary. B. depressinerva is proposed to be Vulnerable (VU) D1, following the guidelines of the IUCN.

A new species of the genus Amigdoscalpellum (Cirripedia, Thoracica, Scalpellidae) from deep waters in the western Pacific

A new species of deep-water barnacle belonging to the family Scalpellidae is described from the western central Pacific. Based on the presence and absence of radial stripes on the surfaces of the plates, the 23 species of the genusAmigdoscalpellumcan be divided into two groups. In the species group with radial stripes, the new species here described,A. dorsituberculatumsp. nov., differs from other species by the dorsal part of the carina being round and arched, the roof without lateral ribs and median furrow; the infra-median latus wider triangular, its length on the basal margin greater than its height; and by the vestigial form of the caudal appendage. A key to the species ofAmigdoscalpellumis provided.

Two new species of Trevathana (Crustacea, Cirripedia, Balanomorpha, Pyrgomatidae) from the Western Indian Ocean and French Polynesia

Two new species of the Pyrgomatid barnacle Trevathana are described: Trevathana synthesysae nov. sp., extracted from Plesiastrea versipora from the Indian Ocean Islands Réunion and Mauritius, and Trevathana isfae nov. sp. from a colony of Favia stelligera from French Polynesia, which, until recently, was terra incognita with regard to coral-inhabiting barnacles. The two new species are distinctive by their relatively broad scutum as compared to Trevathana dentatum, their prominent adductor ridge extending beyond the basal margin of the scutum, and their quadrangular tergum.

Diphascon (Diphascon) dolomiticum, a new species of Hypsibiidae (Eutardigrada) from Italy

A new species of eutardigrade, Diphascon (Diphascon) dolomiticum sp. n., is described. It has three macroplacoids and microplacoid; claws short and stout; hind legs with basal margin indented; internal and external claws on the first three pairs of legs almost of the same length; anterior claws on the hind legs longer than the posterior claws.

An Early Triassic conodont with periodic growth?

Elements of a new Triassic conodont genus Parapachycladina, from the Lower Triassic Beisi Formation of western Guangxi Province, China, show a characteristic pattern of lamellar edges in the recessive basal margin. The lamellae are grouped in sets of 8–10, with broad interlamellar spaces between each set. If this apparent periodicity reflects annual cycles, the specimens were not more than four years old when they ceased growing.

A coral-eating barnacle, revisited (Cirripedia, Pyrgomatidae)

The coral-eating barnacle Hoekia monticulariae (Gray, 1831), the only internal parasite among the Thoracica described to this day, is characterized by an irregularly-shaped shell nestled cryptically between the polyps of the hermatypic coral Hydnophora Fischer, 1807, which occurs throughout most of the Indo-West Pacific. Because of its protean form, cirripedologists have failed to appreciate the diversity of taxa related to Hoekia, a presumed monotypic genus. We describe seven new species divided between Hoekia and three new genera, Eohoekia, Parahoekia, and Ahoekia for which the Tribe Hoekiini is proposed. As in other pyrgomatids, calcareous overgrowth by the coral is inhibited around the edge of the wall and aperture. But in Hoekiini a pseudopolyp, upon which the barnacle feeds with modified trophi, covers the wall and aperture. Furthermore, rather than articulating with a calcareous basis, the wall is suspended in coral tissue. Its hypertrophied lateral margin ( = basal margin), in contact with the host’s tissue, is the site where metabolic activities are inferred to take place. In Hoekia and Ahoekia, the wall develops simple or connecting tubes that lead to openings in the margin, which serve as circulatory pathways. A hypertrophied margin and elaborated circulatory system suggests that the Hoekiini may not be wholly dependent on feeding directly on host tissue and/or coelenteronic material, but may also be absorptive parasites. Although other pyrgomatids, in the tribes Pyrgopsellini nov. and Pyrgomatini nov., exercise some control over their hosts by an apertural frill and through discontinuities between the shell and basis, they are still planktotrophic.

The mechanism of plication inception in palm leaves: histogenetic observations on the palmate leaf of Rhapis excelsa

Plications in the leaf of Rhapis excelsa are initiated at the lateral, basal margin of the palmate lamina and are oriented vertically from inception. When first initiated the plications appear in transection as distinct, sinusoidal folds. However, with the addition of more folds laterally, the earlier pleats become more markedly appressed and constrained to grow more symmetrically in a radial plane. As a result of asymmetry of the entire leaf the cathodic side of the lamina which abuts against the next oldest leaf shows an earlier folding and more radial, symmetrical growth than the anodic, free margin. However, there is no evidence of a significant developmental difference among plications in different regions of the blade. Changes in shape from the unplicated apex of the fold to its markedly plicated base parallel precisely the changes in shape exhibited by a single plication position followed through time. Quantitative observations on plication growth demonstrate that initially there is more extensive upgrowth in the adaxial plication ridges than their abaxial counterparts. But adaxial ridge formation is correlated with cell division whereas abaxial protuberance is the result almost exclusively of cell enlargement. Once a pattern of alternating adaxial and abaxial ridges is established, plication growth shifts from the ridges to the intercostal zones between the ridges and occurs by cell division with no net cell enlargement during the early phases studied. These quantitative observations indicate that increases in plication furrow depth are a result of ridge upgrowth rather than cell separation, and histogenetic observations give no sign of protodermal disruption and redifferentiation. Plication inception in Rhapis is therefore a result of meristem folding and not tissue cleavage. Because quantitative measurements of plication origin and growth in Rhapis are virtually identical to those described in the pinnate palm Chrysalidocarpus lutescens, we conclude that morphogenetic processes are the same and that differing plication shape between them is merely a consequence of physical features within the leaf itself and does not indicate different morphogenetic mechanisms as suggested in the past.

DESCRIPTIONS OF SOME GENERA AND SPECIES OF LEIODIDAE (COLEOPTERA)

Male. Length 2.2 mm. Second and third antennal segments equal in length. Punctures of the pronotum evident, those of the elytral intervals very indistinct. Metasternum very indistinctly alutaceous near the lateral margin; the punctures fine and close at middle except on the impunctate area, a trifle coarser on the sides and there distinct but not deeply impressed, very closely placed, the punctures of the anterior margin like those of the disk. Each abdominal segment finely and closely punctate, without coarser punctures on the basal margin.

COLEOPTERA OF THE NORTH SHORE OF THE GULF OF THE ST. LAWRENCE

Length 2.3-2.4 mm. ; width 1.1 mm. Elongate, suboval, moderately convex, fulvo-pubescent. Piceous with distinct aeneous lustre; each elytron with two yellow spots; the one as long as wide, including hunerus and basal margin and extending inwardly to the third interval; the other elongate oval and slightly oblique, extending from apical third to a point near apex.