A total of 900 coral fragments collected across 2 fringing reefs located southwest of Mexico, La Entrega (LE) and San Agustín (SA), were examined for the presence of boring sponges. Of all samples, 43% were invaded by boring sponges, and 7 species belonging to 5 genera (Aka, Cliona, Pione, Cliothosa and Thoosa) were identified. The most abundant species were Cliona vermifera (17.9%), Cliona sp. (10.8%), A. cryptica (7.8%) and P. carpenteri (6.0%). The distribution and abundance of the species varied considerably throughout the reef area (margin and platform) and displayed certain selectivity for specific calcareous substrata. C. vermifera, Cliona sp., A. cryptica and P. carpenteri were most common on the reef margins, while T. calpulli was common on the central platform. A. cryptica, P. carpenteri, and Cliothosa hancocki were frequently found living in the immediate vicinity of live coral tissue, contrary to C. vermifera, T. calpulli and Cliona mucronata, which preferentially bored coral rubble. The results showed that reef margins had a significantly higher infestation level than the platforms (mean infestations of 60.6 and 26.2%, respectively). There were also differences between reefs. The infestation was higher on LE than on SA (48.6 and 38.2%, respectively), and these differences were larger between the platforms of the 2 reefs (41.3 and 11.1%, respectively). In general, the results of the present study have demonstrated that the diversity and abundance of species, as well as the infestation of coral frameworks by sponges, was significantly higher in the margin at both reefs studied and on the platform of LE, where the availability of exposed carbonate substrate was higher. In the margin of these reefs, the consequences of boring went far beyond the mere hollowing out of a few cavities, since by weakening the coral's attachment to the substrate, the sponges accelerated coral loss and restructured the reef edge. This pattern may have important implications for the preservation of the reef framework. KEY WORDS: Bioerosion · Boring sponges · Fringing coral reefs · Reef margin · Reef flat · Mexican PacificResale or republication not permitted without written consent of the publisher Mar Ecol Prog Ser 356: 113-122, 2008 different types of organisms, which act on the environment in a wide variety of ways, interact with the ecosystem and with each other as part of the cycle of reef growth and degradation (Macdonald & Perry 2003). Amongst these, the boring sponges are considered one of the main agents that modify coral reef ecosystems (Goreau & Hartman 1963, MacGeachy 1977. Globally, they are the most common type of macroendolith and are responsible for more internal degradation of coral than any other group of organisms, internally (Perry 1998). They can accelerate the erosion of the reef framework (Tunnicliffe 1979) and cause a shift in the carbonate balance (Rose & Risk 1985). Sponges obviously play one of the most important roles in bioerosion worldwide. However, they have been omitted in most stud...

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Abstract. Individuals of the recently described demosponge Thoosa mismalolli are common on Mexican Pacific coral reefs, excavating burrows in living corals and in other calcareous substrata. To better understand the propagative abilities of this sponge, we conducted a histological study over an 18‐month period (May 2007–November 2008) to identify sexual and asexual reproductive structures. Members of the species are viviparous and hermaphroditic, with various developmental stages of oocytes, spermatic cysts, and embryos co‐occurring in the mesohyl for most of the year. This nearly continuous reproductive activity intensified during the warm season. Fertilization was internal, and embryos developed inside the parental sponge to produce an unciliated hoplitomella larva, characterized by a peculiar siliceous skeleton. In addition to the sexually generated larvae, adults of T. mismalolli formed gemmules for asexual reproduction. Gemmules occurred within the mesohyl during all months of the year, but were most abundant in the coldest months. This combination of sexual and asexual processes enables individuals of T. mismalolli to reproduce almost continuously. This strategy may facilitate both long‐term persistence within reefs and effective dispersal between distant reefs.

Scutellastra mexicana is the largest known patellid limpet species and probably is one of the most endangered marine invertebrates. The species was once distributed along the American Pacific coast from Mexico to Peru, but their large size (up to 35 cm long) and easy accessibility (shallow sublittoral), made it very vulnerable to human collection and now is extinct on most of the mainland Mexican coast. In August 2017, a large population of this species was found on María Cleofas island, off the coast of west‐central Mexico (Marías Archipelago, Pacific Ocean). This constitutes the only report of a population of this species since 1988. A total of 808 adult individuals of up to 26 cm in length and 20 cm in width were estimated, together with the presence of juveniles, suggesting that it is a self‐sustaining population. The population was monitored in August 2017 and August 2018. Although the species is under the category ‘Special Protection’ in the General Mexican Wild Law, and that María Cleofas island is a Biosphere Reserve, fishermen that operate with impunity in the area decimated the limpet population within a year of its discovery. Abundance in the shallowest area decreased significantly from 120 individuals per transect (65 m long and 2.75 m wide) in August 2017 to 48 individuals in August 2018, and the estimated adult population decreased from 808 to 304 limpets. Neither passive national conservation policies nor local practices have reduced current threats to biodiversity and resource depletion in Marías Archipelago. Protected areas like this are ‘paper parks’—parks in name only—because there is no active conservation strategy or protection of marine species.

Three new species of coral reef boring sponges were found in remote coral reefs from Revillagigedo Island, an archipelago that is 386 km from the continent.Cliona medinaesp. nov. is a sponge with orange-yellow papillae characterized by short almost straight spirasters.Cliona tropicalissp. nov., is a yellow papillate sponge with a spicule complement similar to the species included in theCliona viridiscomplex. However, the new species differs from the rest of the species mainly in its external morphology and by differences in the size and shape of spicules.Thoosa purpureasp. nov. is characterized by its purple colour, and the spicular complement formed by tylostyles, two amphiaster categories, bi- tri- and tetra-radiate oxyasters and smooth or microspined centrotylote oxeas. In addition,Cliothosa tylostrongylatasp. nov. is also described from coral reefs from the southern Mexican Pacific Ocean. This is a light red species, with tylostyles and tylostrongyles as megascleres and ramose and nodulose amphiasters as microscleres. The four species were found exclusively excavating skeletons of live or dead corals of the genusPocillopora. This study increases the number of boring sponges known from the Mexican Pacific Ocean to 22 species and it is the first study on marine sponge fauna from the Revillagigedo archipelago.