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Petrarca is an ascothoracidan endoparasite in scleratinian dendrophyllid corals. Petrarca can stimulate coral growth, forming a gall chamber to house itself inside the coral skeleton. The diversity, molecular phylogeny and feeding ecology of Petrarca are understudied. This is the first study of Petrarca to be based on light and scanning electron microscopy to document the fine-scale external and functional morphology of its trophi and other structures. A combined molecular and morphological approach revealed at least four closely related species of Petrarca, P. goanna, P. morula, Petrarca nozawai sp. nov. and Petrarca rubus sp. nov. in Turbinaria and Astreopora corals in Asia. Carapace shape and fine morphology, ultrastructure of the antennular aesthetasc, morphological characteristics of the trophi and the shape and size of the penis rami are diagnostic characters. Several morphological characters, which are all probably synapomorphies, have been proposed to distinguish the genus Petrarca from other Ascothoracida. Mouthparts morphology of Petrarca are developed for cutting and chewing, rather than for piercing and sucking as in many other Ascothoracida. The external surface of the carapace of Petrarca is ornamented with densely packed secretory papillae used putatively for the chemical dissolution of the substrate necessary for the formation of the gall chamber.

Highly specialized cryptochirid crabs are obligate symbionts of scleractinian corals in tropical and subtropical seas. General morphologies of cryptochirid crabs remain poorly described due to their small size and difficulties in collection; thus, the current inventory is probably an underestimation. In the present study, we sampled cryptochirid crabs from coral communities in Hong Kong. In the literature, onlyCryptochirus hongkongensis(nowNeotroglocarcinus hongkongensis) with unknown hosts had been recorded in Hong Kong since 1936. In addition to morphological examination, identification in the present study is further supported by sequence divergence of mitochondrial cytochrome c oxidase I (COI) and 16S ribosomal DNA markers. Six operative taxonomic units (OTUs), representing four species and one species complex with two species, were revealed among our material:Cryptochirus coralliodytes,Lithoscaptus paradoxus,Lithoscaptus doughnutsp. nov.,Lithoscaptus scottaesp. nov., andXynomaia shenispecies complex. Morphological description of these species is provided, including description of the two new pseudocryptic species. The hosts of the genusLithoscaptusbelong largely to the Merulinidae, whileL. doughnutsp. nov. inhabits the Plesiastreidae.

Octomerisis a chthamalid intertidal barnacle with eight shell plates. There are currently two species of such barnacles:O. brunneaDarwin, 1854 (type locality in the Philippines), common in the Indo-Pacific region, andO. angulosaSowerby, 1825, only recorded in South Africa.Octomeris intermediaNilsson-Cantell, 1921, identified from the Mergui Archipelago in Myanmar, was considered to be conspecific withO. brunneaby Hiro (1939) based on samples collected in Taiwan. The morphological differences in shell and opercular plates betweenO. brunneaandO. intermediaare believed to be intra-specific variations due to different degrees of shell erosion. In the present study, the genetic and morphological differentiations ofOctomerisin the Indo-Pacific region were examined. This study found two molecular clades (with inter-specific differences) based on the divergence in the COI genes, and the species also have distinct geographical distributions. TheOctomeris brunneaclade covers samples collected from the Philippines and Taiwan waters and the other clade, which we argue isO. intermedia, is distributed in Phuket and Krabi, Thailand and Langkawi, Malaysia. Phuket and Krabi are located approximately 300 km south of the Mergui Archipelago, the type locality ofO. intermedia. The morphology of samples collected from Thailand fits the type description ofO. intermediain Nilsson-Cantell (1921). Our study concludes thatO. intermediais a valid species based on morphological and molecular evidence.

Biology of planktonic stomatopod larvae has long remained poorly understood and often considered “black boxes” in life history studies. From coralline crustose algal (CCA) reefs at Datan, Taoyuan, Taiwan, using light traps recently designed, we collected considerable number of stomatopod larvae and juveniles. Applying DNA barcoding techniques using mitochondrial cytochrome oxidase I (COI) and 16S ribosomal RNA (16S rRNA) gene sequences, 14 morphotypes were revealed to represent 12 distinct species, seven of which identified to species level by comparing against reference sequences available from online source (GenBank), whereas the other five do not cluster with any known sequences. All stomatopod larvae and juveniles were described and illustrated. We report Manningia pilaensis (De Man, 1888) and Levisquilla jurichi (Makarov, 1979) as new records of the stomatopod fauna of Taiwan and confirm the validity of Lysiosquillina maculata (Fabricius, 1793). Based on material we acquired from light traps, which include propelagic antizoea larvae (of L. maculata), and also postlarval and juvenile forms (of various squillid species), both positively phototactic, indicating the current understanding of negative-positive-negative phototactic tendency from early planktonic to postlarval stages through the development of stomatopod larvae, might not be as distinct as previously described.