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<bold>Abstract</bold> Mitochondrial tRNA gene loss and cytosolic tRNA import to mitochondria are two common phenomena in mitochondrial biology, but their importance is often under-appreciated in animals. This is because most bilaterally symmetrical animals (Bilateria) encode a complete set of tRNAs needed for mitochondrial translation. By contrast, studies of mitochondrial genomes in non-bilaterian animals have shown a reduced tRNA gene content in several lineages, necessitating tRNA import. Interestingly, in most of these lineages tRNA gene content appears to be set early in the evolution of the group and conserved thereafter. Here we demonstrate that Clade B of Haplosclerid Sponges (CBHS) represent an exception to this pattern. We determined mt-genome sequences for eight species from this group and analyzed them with six that had been previously available. In addition, we determined mt-genome sequences for two species of haploslerid sponges outside the CBHS and used them with eight previously available sequences as outgroups. We found that tRNA gene content varied widely among CBHS species: from three in an undescribedHaliclonaspecies (Haliclona sp. TLT785) to 25 inXestospongia mutaandX. testudinaria. Furthermore, we found that all CBHS species outside the genusXestospongialackedatp9, while some also lackedatp8. Analysis of nuclear sequences fromNiphates digitalisrevealed that bothatp8andatp9had transferred to the nuclear genome, while the absence of mt-tRNA genes represented their genuine loss. Overall, CBHS can be a useful animal system to study mt-tRNA genes loss, mitochondrial import of cytosolic tRNA, and the impact of both of these processes on mitochondrial evolution. Significance statementIt is generally believed that the gene content is stable in animal mitochondrial (mt) DNA. Indeed, mtDNA in most bilaterally symmetrical animals encompasses a conserved set of 37 genes coding for 13 proteins, two rRNAs and 22 tRNAs. By contrast, mtDNA in non-bilaterian animals shows more variation in mt gene content, in particular in the number of tRNA genes. However, most of this variation occurs between major non-bilaterian lineages. Here we demonstrate that a group of demosponges called Clade B of Haplosclerid Sponges (CBHS) represents a fascinating exception to this pattern, with species experiencing recurrent losses of up to 22 mt-tRNA genes. We argue that this group constitutes a promising system to investigate the effects of tRNA gene loss on evolution of mt-genomes as well as mitochondrial tRNA import machinery. 

This study presents a comprehensive taxonomic revision of the family Suberitidae (Porifera: Demospongiae) for California, USA. We include the three species previously known from the region, document two additional species previously known from other regions, and formally describe four new species as Pseudosuberites latke sp. nov., Suberites californiana sp. nov., Suberites kumeyaay sp. nov., and Suberites agaricus sp. nov. Multi-locus DNA sequence data is presented for seven of the nine species, and was combined with all publicly available data to produce the most comprehensive global phylogeny for the family to date. By integrating morphological and genetic data, we show that morphological characters may be sufficient for regional species identification but are likely inadequate for global classification into genera that reflect the evolutionary history of the family. We therefore propose that DNA sequencing is a critical component to support future taxonomic revisions. 

California's network of marine protected areas was created to protect the diversity and abundance of native marine life, but the status of some taxa is very poorly known. Here we describe the sponges (phylum Porifera) from the Carmel Pinnacles State Marine Reserve, as assessed by a SCUBA-based survey in shallow waters. Of the 29 sponge species documented, 12 (41%) of them were previously unknown. Using a combination of underwater photography, DNA sequencing, and morphological taxonomy, we greatly improve our understanding of the status and distribution of previously described species and formally describe the new species as Hymedesmia promina sp. nov., Phorbas nebulosus sp. nov., Clathria unoriginalis sp. nov., Clathria rumsena sp. nov., Megaciella sanctuarium sp. nov., Mycale lobos sp. nov., Xestospongia ursa sp. nov., Haliclona melissae sp. nov., Halichondria loma sp. nov., Hymeniacidon fusiformis sp. nov., Scopalina carmela sp. nov., and Obruta collector gen. nov., sp. nov. An additional species, Lissodendoryx topsenti (de Laubenfels 1930), is moved to Hemimycale, and H. polyboletus comb. nov., nom. nov. is created due to preoccupation by H. topsenti (Burton, 1929). Several of the new species appear to be rare and/or have very restricted distributions, as they were not found at comparative survey sites outside of Carmel Bay. These results illustrate the potential of qualitative presence/absence systematic surveys of understudied taxa to discover and document substantial novel diversity.  

Sponges are common and diverse in California, but they have received little study in the region, and the identities of many common species remain unclear. Here we combine fresh collections and museum vouchers to revise the order Axinellida for California. Seven new species are described: Endectyon (Endectyon) hispitumulus, Eurypon curvoclavus, Aulospongus viridans, Aulospongus lajollaensis, Halicnemia litorea, Halicnemia montereyensis, and Halicnemia weltoni. One new combination is also described, and two existing species are reduced to junior synonyms, resulting in a total of 13 species; a dichotomous key to differentiate them is provided. DNA data from 9 of the 13 species is combined with publicly available data to produce updated global phylogenies for the order.   

Sponges (phylum Porifera) are common inhabitants of kelp forest ecosystems in California, but their diversity and ecological importance are poorly characterized in this biome. Here I use freshly collected samples to describe the diversity of the order Scopalinida in California. Though previously unknown in the region, four new species are described here: Scopalina nausicae sp. nov., S. kuyamu sp. nov., S. goletensis sp. nov., and S. jali sp. nov.. These discoveries illustrate the considerable uncharacterized sponge diversity remaining in California kelp forests, and the utility of SCUBA-based collection to improve our understanding of this diversity.  

Sponges (phylum Porifera) are ubiquitous inhabitants of marine ecosystems and have been shown to provide substantial ecosystem services. Despite this ecological importance, the sponge fauna in California has received little study. Here I use a collection of kelp forest sponges to describe the diversity of the order Tethyida in California. This order contains the genus Tethya, which has been included in long-term ecological monitoring projects. I show that Tethya vacua is a junior synonym of Tethya californiana, and thus all Tethya populations known in California belong to a single species. Genetic data from California's only Timeidae, Timea authia, indicate that this species is in fact in the Tethyidae and is the third known member of the genus Tethytimea. I also describe the first member of the family Hemiasterellidae from the Eastern Pacific, Galaxia gaviotensis gen. nov. sp. nov. By combining field photographs, morphological taxonomy, and phylogenetic analysis of these samples, this work will facilitate future efforts to understand the evolution of this order and the ecological role of sponges in the California kelp forest.