María Ana Tovar-Hernández

Fouling polychaete worms from the southern Gulf of California: Sabellidae and Serpulidae.

Abstract Members of the tubicolous polychaete families, Sabellidae and Serpulidae, constitute two of the most important groups in the marine fouling biota. This paper describes three fouling sabellids and six serpulids from the southern Gulf of California and provides information about the reproductive biology of these species. The invasive species, Branchiomma bairdi and Ficopomatus miamiensis, are established in the southern Gulf of California as self‐sustaining populations outside of their native range of the Caribbean Sea. Hull fouling is considered the most probable vector for the translocation of B. bairdi to the eastern Pacific, while the presence of F. miamiensis is most likely due to shrimp aquacultural activities. Hydroides elegans is probably an invasive species in the study area and is common as fouling on ships and piers in the Caribbean, Gulf of Mexico, the Turkish Levantine coast, Hawaii and California. Hydroides brachyacanthus has been widely recorded in the Mexican Pacific. Demonax pallidus and Megalomma coloratum constitute new records for México. Hydroides elegans, H. recurvispina and Vermiliopsis multiannulata are new records for the Mazatlán port. Hydroides cruciger, H. brachyacanthus, H. elegans, H. recurvispina and Megalomma coloratum have separate sexes without sexual dimorphism. Branchiomma bairdi and D. pallidus are simultaneous hermaphrodites, although asexual reproduction via scissiparity is documented in B. bairdi. Sperm morphology (spherical nucleus, rounded or subtriangular cap‐like acrosome and a long flagellum) suggests that the species recorded here are free‐spawners with external fertilisation or ect‐aquasperm type. This taxonomic effort is greatly enhanced by the integration of synonymies, characterisations and image collections with annotations archived in Morphbank.

Branchiomma bairdi : a Caribbean hermaphrodite fan worm in the south-eastern Gulf of California (Polychaeta: Sabellidae)

Branchiomma bairdi , a fouling non-indigenous sabellid polychaete has been detected in the south-eastern Gulf of California, representing the first record in the eastern tropical Pacific, as its original distribution is the Caribbean Sea. The species was commonly found as isolated specimens but small aggregates with 4–12 individuals were also found on floating docks, on dock pilings, buoys and on hulls of vessels in the port of Mazatlan. Branchiomma bairdi is a simultaneous hermaphrodite with male and female gametes developing separately in the same segments. The sperm morphology suggests that the species is a free-spawner with external fertilization (ect-aquasperm type). A complete diagnosis is provided and a discussion about its systematics, reproduction and ecology is included.

Reproduction of the invasive fan worm Branchiomma bairdi (Polychaeta: Sabellidae)

Abstract The fan worm Branchiomma bairdi has been introduced to the Gulf of California from its original distribution in the Caribbean Sea, and is now a conspicuous component of most benthic communities. Study of reproductive features is essential to understand the dispersion capability of B. bairdi and its invasive potential. Sampling was carried out monthly in the port of Mazatlán during 2009 (23°12′13′′N, 106°24′31.4′′W). Abundance and biomass were measured. Sex and maturity were determined. Gametogenesis and observations on the spawning, fertilization, larval development and brooding are presented. The highest values of abundance (>2500 worms m−2) and biomass (175 g m−2) occurred during August and September. Mature simultaneous hermaphrodite worms were found continuously throughout the annual cycle as well as asexual forms. In B. bairdi gametogenesis is extra-ovarian. Three posterior thoracic segments and all abdominal segments are involved in the production of gametes. Sperm are ect-aquasperm type (free spawners with external fertilization). Spermatids are grouped in tetrads. Ovules are retained for intra-tubular fertilization. Larval development is lecithotrophic. Embryos are brooded on the collar and branchial crown.

Distribution and diversity of the Syllidae (Annelida: Polychaeta) from the Mexican Gulf of Mexico and Caribbean

The objective of this study was to contribute to the knowledge of the syllids distributed in the eastern coasts of Mexico (Gulf of Mexico and Caribbean) taking into consideration their composition, distribution and diversity. Sampling was done at 77 stations including 49 in soft bottoms (terrigenous and carbonate sediments), and 28 in hard bottoms (coralline substrates) sampled in nine reef zones included in three reef systems (Veracruz, Campeche and Cozumel). In all 2084 individuals were collected (13.5% in soft sediments and 86.4% in coralline areas). Forty-five species were identified: 31 in soft bottoms and 38 in corals, with 21 species common to both types of environments. In soft bottoms, the highest species richness and diversity were found in the Carbonate Zone, while syllids were uncommon in the Terrigenous Zone. In hard bottoms, the highest density, species richness and diversity values were found in the Veracruz Reef System, followed by the Campeche Bank and Cozumel Island Reef Systems. The dominant species in soft bottoms were Haplosyllis spongicola, Exogone lourei, Typosyllis cornuta and T. papillosus, whereas T. alosae, T. corallicola, T. cornuta and H. spongicola dominated in hard bottoms. The importance and success of the syllids in both soft bottoms and reef environments, particularly in those of the Gulf of Mexico is emphasized.

Caruncle in Megalomma Johansson, 1925 (Polychaeta: Sabellidae) and the description of a new species from the Eastern Tropical Pacific

The presence of a caruncle in the polychaete family Sabellidae is documented. It is placed dorsally above the mouth, between the dorsal lips, supported with hyaline cartilage constituted by a homogeneous eosinophilic matrix and it is innervated directly from the cerebral ganglion. The caruncle surface has four longitudinal ciliated bands; the cilia from the lateral bands are hypertrophied, wider distally, tongue‐like, forming a ciliated curtain or membranella. The genus Megalomma is emended based on the presence of a caruncle, a long dorsalmost radiolar pair, a high number of radiolar skeletal cells, and the presence of interramal eyespots. We describe a new species from Acapulco in the Tropical Eastern Pacific –Megalomma carunculata sp. nov. It has a caruncle, subtriangular ventral lappets, well developed dorsal pockets, compound eyes in all radioles, and interramal eyespots in the thoracic and abdominal segments.

Revision of Chone Kr⊘yer, 1856 (Polychaeta: Sabellidae) from North America and descriptions of four new species

The present study deals with the revision of type and non‐type material from 12 species of Chone Krøyer, 1856 (Polychaeta: Sabellidae) that have been described from North America: C. albocincta Banse, 1972, C. aurantiaca (Johnson, 1901), C. bimaculata Banse and Nichols, 1968, C. ecaudata (Moore, 1923), C. gracilis Moore, 1906, C. magna (Moore, 1923), C. minuta Hartman, 1944, C. mollis (Bush in Moore, 1904), C. picta (Verrill, 1885), C. princei McIntosh, 1916, C. ungavana Chamberlin, 1920, and C. veleronis Banse, 1972; and the formal description of four new species: Chone eiffelturris n. sp., Chone paramollis n. sp., Chone quebecensis n. sp., and Chone trilineata n. sp. Chone princei is redescribed and transferred to the genus Jasmineira Langerhans, 1880; C. ungavana is declared incertae sedis; C. bimaculata is reinstated; C. minuta is synonymized with C. ecaudata, and C. mollis is recorded for the Pacific coast of Panama.

Is Hydroides brachyacantha (Serpulidae : Annelida) a widespread species?

Abstract. Hydroides brachyacantha Rioja, 1941, an important fouling serpulid species originally described from Mazatlán (Southern Gulf of California, Mexico) and Acapulco (southern Mexican Pacific), has been reported from the Mexican Pacific and numerous tropical and subtropical localities. However, a recent description of H. amri Sun, Wong, ten Hove, Hutchings, Williamson & Kupriyanova, 2015 from Australia, which was historically misidentified as H. brachyacantha, suggested that the widespread ‘H. brachyacantha’ is indeed a species complex. To test the status of H. amri, we conducted phylogenetic analyses based on a combined dataset of 18S rRNA, internal transcribed spacer-2, and cytochrome b sequences of H. brachyacantha from the type locality in Mexico with those of H. amri from Australia. Our molecular data supported the morphology-based hypothesis of H. amri and H. brachyacantha sensu stricto as two distinct species. Furthermore, H. amri comprises two non-sister well-supported clades. Hydroides amri thus comprises what we consider two cryptic species with long-term isolation. Here we describe the genetic lineage in South Australia as Hydroides nikae, sp. nov. Given the absence of a holotype of H. brachyacantha, we designate a neotype collected from the type locality (Mazatlán, Mexico). This study calls for a worldwide revision of the H. brachyacantha-complex.

Parasabella Bush, 1905, replacement name for the polychaete genus Demonax Kinberg, 1867 (Annelida, Polychaeta, Sabellidae)

Abstract Parasabella Bush, 1905 is reintroduced as a replacement name for Demonax Kinberg, 1867 (Annelida: Polychaeta: Sabellidae) which is a junior homonym of Demonax Thomson, 1860 (Insecta: Coleoptera: Cerambycidae).

Phylogeny of Chone Krøyer, 1856 (Polychaeta: Sabellidae) and related genera

An analysis was undertaken to test the monophyly of the sabellid genus Chone Krøyer using maximum parsimony methodology. Cladistic analysis revealed three monophyletic genera whose respective members were assigned previously to Chone. Chone sensu stricto (containing the type species) is defined by the presence of broadly rounded dorsal lips and thoracic uncini with a large tooth above the main fang, followed by a series of smaller teeth. Dialychone Claparède is re‐established for the second genus and a new name – Paradialychone – is proposed for terminals nested in the third clade. Dialychone and Paradialychone gen. nov. are the sister groups of Chone, defined by the presence of a simple pre‐pygidial depression and modified posterior abdominal uncini. Amphicorina Claparède is basal within Sabellinae and Euchone Malmgren is the sister group of Chone, Paradialychone gen. nov. and Dialychone. The analysis supports the transfer of C. princei and C. reayi to Jasmineira Langerhans. Present address: Laboratorio de Invertebrados Bentónicos, Instituto de Ciencias del Mar y Limnología, Unidad Académica Mazatlán, Universidad Nacional Autónoma de México, Calzada Joel Montes Camarena s/n, 82000, Mazatlán, Sinaloa, Mexico.

A New fouling Hydroides (Annelida, Sabellida, Serpulidae) from southern Gulf of California

Members of the tubicolous polychaete family Serpulidae constitute one of the most important groups of marine fouling biota. This paper describes a new species of the serpulid genus Hydroides from dock fouling at Mazatlan (southern Gulf of California), providing information about live colouration and reproductive features. Hydroides dolabrus sp. nov. belongs to a subgroup of species in which verticil spines are equal in size and shape, lack both external and lateral spinules, but have various modifications to their tips. However, Hydroides dolabrus sp. nov. is distinct in having tips of verticil spines pickaxe-shaped, with asymmetrical triangular radially orientated projections: the internal projections are short and point inward the verticil centre, while longer external projections point outward the verticil centre. Like all species of the genus, H. dolabrus sp. nov. is a gonochoristic broadcast spawner lacking sexual dimorphism. A phylogenetic analysis of Hydroides based on COI, 18S and cyt b sequence data reveals that H. dolabrus sp. nov. is genetically distinct from other species of Hydroides for which sequence data are available. The new species is the 11th in the genus described from Mexican waters.