This paper is a collection of novel distributional records of 20 species belonging to 8 phyla (Chlorophyta, Rhodophyta, Cnidaria, Ctenophora, Annelida, Mollusca, Arthropoda and Chordata) from 11 Mediterranean countries, namely, Spain: an additional record of the Canary dentex Dentex canariensis is reported from Spain (Valencia), this is the northernmost record of this species in the Mediterranean; Algeria: the first documented record of Caulerpa chemnitzia is reported from the Algerian coast; France: the first record of the Spotted sea hare Aplysia dactylomela is reported from the eastern coast of Corsica; Italy: the first records of the Lessepsian polychaete Dorvillea similis and the alien bivalve Isognomon legumen are reported from Italian waters while additional records of Mnemiopsis leidyi in the south Adriatic are provided;  Libya: the first record of an alien mollusc Crepidula fornicata is reported from Libyan waters; Malta: multiple sightings of gelatinous species Apolemia uvaria, Phacellophora camtschatica and Physophora hydrostatica are reported for the first time from Maltese waters, as well as the first tentative record of the Orange-spotted grouper Epinephelus cfr. coioides; Greece: an occurrence of a rare Bigeye thresher shark Alopias superciliosus is reported from Hellenic Ionian waters, while the first records of the alien Mertens’ prawn-goby Vanderhorstia mertensi, the recently described cyclopoid copepod Oithona davisae and the alien red seaweed Asparagopsis armata are reported from the Aegean Sea. The presence of the micromollusc Euthymella colzumensis is confirmed for Greece; Cyprus: the first record of the red cornetfish Fistularia petimba is reported from Cyprus; Turkey: the first record of the alien jellyfish Marivagia stellata is reported from south-eastern Turkey; Israel: the first records of the sea nettle Chrysaora sp. in the Levant are reported.

The Collective Article ‘New Mediterranean Biodiversity Records’ of the Mediterranean Marine Science journal offers the means to publish biodiversity records in the Mediterranean Sea. The current article is divided in two parts, for records of native and alien species respectively. The new records of native species include: the neon flying squid Ommastrephes bartramii in Capri Island, Thyrrenian Sea; the bigeye thresher shark Alopias superciliosus in the Adriatic Sea; a juvenile basking shark Cetorhinus maximus caught off Piran (northern Adriatic); the deep-sea Messina rockfish Scorpaenodes arenai in the National Marine Park of Zakynthos (East Ionian Sea, Greece); and the oceanic puffer Lagocephalus lagocephalus in the Adriatic Sea.The new records of alien species include: the red algae Antithamnionella elegans and Palisada maris-rubri, found for the first time in Israel and Greece respectively; the green alga Codium parvulum reported from Turkey (Aegean Sea); the first record of the alien sea urchin Diadema setosum in Greece; the nudibranch Goniobranchus annulatus reported from South-Eastern Aegean Sea (Greece); the opisthobranch Melibe viridis found in Lebanon; the new records of the blue spotted cornetfish Fistularia commersonii in the Alicante coast (Eastern Spain); the alien fish Siganus luridus and Siganus rivulatus in Lipsi Island, Dodecanese (Greece); the first record of Stephanolepis diaspros from the Egadi Islands Marine Protected Area (western Sicily); a northward expansion of the alien pufferfish Torquigener flavimaculosus along the southeastern Aegean coasts of Turkey; and data on the occurrence of the Lessepsian immigrants Alepes djedaba, Lagocephalus sceleratus and Fistularia commersonii in Zakynthos Island (SE Ionian Sea, Greece).

The “New Mediterranean Biodiversity Records” series includes new records of marine species found in the Mediterranean basin and/or information on the spatial distribution of already established species of particular interest. The current article presents information on 20 marine taxa classified per country according to their geographic position in the Mediterranean, from west to east. The new records per ecoregion are as follows: Algeria: the first record of the fish Etrumeus golanii is reported along the Algerian coast. Tunisia: the alien jellyfish Phyllorhiza punctata is reported for the first time in the Gulf of Gabès. Italy: the first record of Siganus rivulatus in the Strait of Sicily and a new record of Katsuwonus pelamis from the central Tyrrhenian Sea are reported. The establishment of the isopod of the genus Mesanthura in the northern Tyrrhenian with some notes on its ecology are also included. Croatia: signs of establishment of the Lessepsian Siganus luridus and the occurrence of the alien mollusc Rapana venosa are reported. Albania: the first record of the elasmobranch Alopias superciliosus and a recent sighting of the rare monk seal Monachus monachus in Albanian waters are given. Greece: signs of the establishment of the fish Parupeneus forsskali and of the ascidian Hermania momus in Hellenic Aegean waters are reported. Turkey: a new record of the fish P. forsskali and of the Acarea of the genus Acaromantis and Simognathus are given, while the first case of Remora australis in association with delphinids and the occurrence of the sea star Coscinasterias tenuispina are reported. Also, the establishment of the two alien species Isognomon legumen and Viriola sp. [cf. corrugata] are presented. Egypt: the fish Bathygobius cyclopterus is reported for the first time in Mediterranean Sea waters. Also, a new record of Pagellus bogaraveo and a first record of Seriola fasciata in Egyptian Mediterranean waters are reported. Lebanon: the first record of Dondice banyulensis is presented.

This is the second collective paper issued in 2019, currently amalgamates new knowledge on the Mediterranean geographic distributions of 17 species from five phyla (six aliens, three cosmopolitans, two east Atlantic records and six natives). The acknowledged species were reported from ten countries, mentioned here from west to east: Spain: first report of the east Atlantic grouper Cephalopholis taeniops in the western Mediterranean and an inclusion of Pontarachna puntulum and Litarachna communis to the pontarachnid fauna of Spain; Morocco: first record of Solea senegalensis from the Moroccan Mediterranean coast; Algeria: a valid confirmation for the presence of Sardinella maderensis; Malta: a first record of the Red Sea stomatopod Erugosquilla massavensis; Italy: a rare observation of the crab Paragalene longicrura from Siciliy and a further integration of the alien brown shrimp Penaeus aztecus to the commercial catch in Sicily; Montenegro: a first record of the Lessepsian bigfin reef squid Sepioteuthis lessoniana from the Adriatic Sea; Turkey: northernmost documentation of the Mediterranean flatworm Prostheceraeus giesbrechtii in the Aegean Sea; Israel: a solid confirmation for the population establishment of both the alien rock shrimp Sicyonia lancifer and two species of angelfish, and a first and deepest record of the crystalline goby Odondebuenia balearica; Lebanon: first record of the jellyfish Pelagia noctiluca; Syria: first records of the crown jellyfish Nausithoe punctate and the smallscale codlet Bregmaceros nectabanus.