Pitombo, F. B. (2004). Phylogenetic analysis of the Balanidae (Cirripedia, Balanomorpha). —Zoologica Scripta, 33, 261–276. Our concept of the family Balanidae has undergone many changes since it was originally proposed, and it is now a more circumscribed group. Nevertheless, there are no studies of the phylogenetic relationships among its currently recognized subfamilies: Balaninae, Concavinae and Megabalaninae. Here, a new suite of characters is presented, thus allowing a better evaluation of the systematics of the group. A fourth subfamily, the Amphibalaninae, is proposed to accommodate Amphibalanus gen. nov. and its allies, and Perforatus gen. nov. is proposed and transferred to the Concavinae (all formerly Balaninae). A phylogenetic analysis of the Balanidae was performed. The results showed that Balaninae is basal to the other three subfamilies as well as Concavinae, and Megabalaninae forms a monophyletic group. Hypotheses of character evolution are presented and discussed. As a general pattern, Concavinae and Megabalaninae have the most derived structures, such as the extension of the lateral margin of the sheath, inner face of radii with a longitudinal abutment, basis multilayered (vesicular) and a spur with infolded margins.

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The benthic communities of fringing and mushroom-shaped shallow-water reefs of the Abrolhos region (southern coast of Bahia) were surveyed. Line transects were used to estimate coral and algal percentage cover. Mussismilia braziliensis is the most conspicuous coral species in the majority of the communities surveyed, but turf algal make up the dominant cover in all but one studied reef. In general, communities on mushroom-shaped reefs have higher diversity and higher coral cover than on fringing reefs. For both reef morphologies, the coral to alga cover ratio does. not show marked differences between annual surveys, despite the high productivity characteristic of the dominant algal species.

BackgroundWe present a multi-locus phylogenetic analysis of the shallow water (high intertidal) barnacle genus Chthamalus, focusing on member species in the western hemisphere. Understanding the phylogeny of this group improves interpretation of classical ecological work on competition, distributional changes associated with climate change, and the morphological evolution of complex cirripede phenotypes.Methodology and FindingsWe use traditional and Bayesian phylogenetic and ‘deep coalescent’ approaches to identify a phylogeny that supports the monophyly of the mostly American ‘fissus group’ of Chthamalus, but that also supports a need for taxonomic revision of Chthamalus and Microeuraphia. Two deep phylogeographic breaks were also found within the range of two tropical American taxa (C. angustitergum and C. southwardorum) as well.ConclusionsOur data, which include two novel gene regions for phylogenetic analysis of cirripedes, suggest that much more evaluation of the morphological evolutionary history and taxonomy of Chthamalid barnacles is necessary. These data and associated analyses also indicate that the radiation of species in the late Pliocene and Pleistocene was very rapid, and may provide new insights toward speciation via transient allopatry or ecological barriers.

Distribution patterns of Chthamalus along the Tropical Eastern Pacific region have not yet been described, mostly due to unknown species ranges and the presence of cryptic species that has biased previous attempts to describe them. Prior to this paper, four formal and two informal species of Chthamalus have been recognized as occurring along the Pacific Americas coast: C. dalli Pilsbry; C. fissus Darwin; C. anisopoma Pilsbry; C. panamensis Pilsbry, Chthamalus sp. “cortezianus” and Chthamalus sp. “mexicanus”. The two informal species were already known to exist, based on previous studies using allozymes and gene sequencing, but their morphological characterizations were not determined, thus preventing their recognition and the ascertainment of their status under the International code of Zoological Nomenclature. The main goal of the present study was to discover the morphological differences that distinguish these two species, to determine their latitudinal range, to establish some relationship among the other species of Chthamalus, and to correlate these with the informal names previously used. Two new species of Chthamalus are described: C. hedgecocki sp. nov. occurring along the Mexican coast (Mexican province) and Chthamalus southwardorum sp. nov. occurring from the Gulf of California (Mexico) to the north of Peru, being a typical member of Panamanian s. l. Province. Both species belong to the Chthamalus fissus group of species as they have bidenticulate setae with basal guards on cirrus II and an absence of conical spines on the outer face of the exopod of cirrus I. The names Chthamalus sp. “cortezianus” is herein associated with C. hedgecocki and Chthamalus sp. “mexicanus” with C. southwardorum. An extensive sympatric distribution of Chthamalus species was noticed along the Eastern Pacific, and Chthamalus panamensis, previously known to be limited to the Panamanian coast, was found up to the Mexican coast in sympatry with C. hedgecocki. The COI genetic divergence between C. panamensis and C. hedgecocki varied between 2.8–4.3 using (GTR+G). We suggest that these species form a sibling pair based on to their morphological, ecological and genetic similarities and their evolution took place along the Eastern Pacific coast after the closure of the Isthmus of Panama. Chthamalus southwardorum is the best choice for a sibling pair with C. proteus, as they share morphological and ecological features; nevertheless they present a very high genetic divergence (24.3 to 25.1 GTR+G). Further studies are needed to clarify the evolutionary processes that led to the evolution of the Chthamalus fissus group of species along the Tropical Eastern Pacific coast and in the Caribbean.