Integrative taxonomy provides a major approximation to species delimitation based on integration of different perspectives (e.g. morphology, biochemistry and DNA sequences). The aim of this study was to assess the relationships and boundaries among Eastern Pacific Aplysina species using morphological, biochemical and molecular data. For this, a collection of sponges of the genus Aplysina from the Mexican Pacific was studied on the basis of their morphological, chemical (chitin composition), and molecular markers (mitochondrial COI and nuclear ribosomal rDNA: ITS1-5.8-ITS2). Three morphological species were identified, two of which are new to science. A. clathrata sp. nov. is a yellow to yellow-reddish or -brownish sponge, characterized by external clathrate-like morphology; A. revillagigedi sp. nov. is a lemon yellow to green, cushion-shaped sometimes lobate sponge, characterized by conspicuous oscules, which are slightly elevated and usually linearly distributed on rims; and A. gerardogreeni a known species distributed along the Mexican Pacific coast. Chitin was identified as the main structural component within skeletons of the three species using FTIR, confirming that it is shared among Verongida sponges. Morphological differences were confirmed by DNA sequences from nuclear ITS1-5.8-ITS2. Mitochondrial COI sequences showed extremely low but diagnostic variability for Aplysina revillagigedi sp. nov., thus our results corroborate that COI has limited power for DNA-barcoding of sponges and should be complemented with other markers (e.g. rDNA). Phylogenetic analyses of Aplysina sequences from the Eastern Pacific and Caribbean, resolved two allopatric and reciprocally monophyletic groups for each region. Eastern Pacific species were grouped in general accordance with the taxonomic hypothesis based on morphological characters. An identification key of Eastern Pacific Aplysina species is presented. Our results constitute one of the first approximations to integrative taxonomy, phylogeny and evolutionary biogeography of Eastern Pacific marine sponges; an approach that will significantly contribute to our better understanding of their diversity and evolutionary history.

Sponges are one of the most conspicuous groups of epibionts in mangrove prop root habitats. However, with the exception of the Caribbean and the Indo-Pacific regions, studies focused on species diversity are lacking in other locations that have high mangrove coverage and are relatively distant from coral reef environments. Because mangrove-root epibiont communities, in general, have been understudied worldwide, this research contributes to filling this knowledge gap. In this study, a total of 30 sponge species (belonging to three subclasses, 14 families and 19 genera) were recorded as epibionts on prop roots of the red mangrove Rhizophora mangle in a tropical coastal ecosystem of the Southern Gulf of Mexico. Of these, five were new records for the Gulf of Mexico, 14 were new for the Mexican coasts of the gulf and 25 were new for the study area. Moreover, a similarity analysis based on presence/absence data of mangrove-associated sponges reported throughout the Western Central Atlantic region revealed that the sponge assemblage from the study area was more similar to those documented in most of the Caribbean locations (Jamaica, Cuba, Martinique, Panama, Venezuela, Belize and Colombia) rather than with those of the Northeast of the Gulf of Mexico, Guadeloupe and Trinidad. This relative intra-regional dissimilarity in the structure of mangrove-associated sponge assemblages may be related to differences in environmental conditions as well as taxonomic effort. The study area, unlike most of the Caribbean locations, is characterized by estuarine conditions and high productivity throughout the year. The inter-site variability recorded in the composition of mangrove-associated sponges was influenced by a set of factors such as salinity, dissolved oxygen and hydrodynamism. This study shows the importance of exploring the mangrove-associated sponge assemblages from different regions of the world as it furthers knowledge of the biodiversity and global distribution of this group.

A new species of Axinyssa Lendenfeld, 1897 (Halichondriidae, Halichondrida) is described from the Mexican Pacific Ocean, which constitutes the first record of the genus in the Eastern Pacific Ocean. Axinyssa isabela sp. nov. is an incrusting to massive cushion-shaped yellow sponge without ectosomal skeleton. The ectosome is simply a thin, translucent, partly detachable collagen layer. The collagen is also abundant in the choanosome, while spicular density is relatively low. The choanosomal skeleton is confused with ascending single spicules or spicules grouped in tracts. The tracts become slightly more organized towards the periphery, protruding on the surface in spicule bundles or in single spicules. Spicules are oxeas and derivates (styles and strongyles), 200 to 780 µm long and 3 to 15 µm thick. So far, despite the sampling of a large number of localities along the Mexican Pacific Coast during the last years, Axinyssa isabela sp. nov. has been found only at National Park “Isla Isabel” (Nayarit, Mexico), where it is relatively common, in vertical walls, small caves and overhangs at depths between 4 and 20 m.

The first record of the previous monotypic genus Tethytimea and the description of a new species from cryptic habitats of Gulf of Mexico are presented. Tethytimea carmelita sp. nov., is a red orange cushion shaped sponge (about 5 mm thick) with a tuberculate to granular surface. The spicular complement is formed by tylostyles (200–1120 µm length), smooth spheres (12.5–55 µm in diameter); megasters-spheroxyasters (12.5–90 µm in diameter); and micrasters in two categories: oxy-strongylasters (12.5–27.5 µm in diameter) and spherotylasters (2.5–25 µm in diameter). The new species differs from the only species known T. tylota (Hentschel, 1912) mainly by differences in the size and shape of spicules. T. tylota possesses tylostyles in two size categories; megasters include giant oxyspherasters up 250 µm and micrasters in a single category. Additionally, to the morphological characteristics, we integrated partial sequences of a large sub-unit ribosomal 28S rDNA gene region (D1–D2 domains), in order to establish the molecular taxonomic position of our new species (and genus). Tree topologies (Maximum Likelihood and Bayesian Inference) were congruent in phylogenetic hypothesis, retrieving the Order Tethyida as monophyletic. In this clade, the family Timeidae was separated from the other families Tethyidae + Hemiastrellidae. Inside this latter group and according to the taxonomic hypothesis based on morphology, Tethytimea carmelita sp. nov. was included in Tethyidae clade, together with a sequence of Tethya sp. (AY626300), forming a sister group with representatives of genera Xenospongia and Thectitethya. Our new species constitutes the second valid known species for the genus Tethytimea and the first record of genus for the Atlantic Ocean.