Gustavo Sanchez

• PhD Hiroshima University
• PostDoc Position at Okinawa Institute of Science and Technology Graduate University

Many female squids and cuttlefishes have a symbiotic reproductive organ called the accessory nidamental gland (ANG) that hosts a bacterial consortium involved with egg defense against pathogens and fouling organisms. While the ANG is found in multiple cephalopod families, little is known about the global microbial diversity of these ANG bacterial s...

Cephalopod fisheries are increasing, but little is known about the cryptic diversity of some key commercial species. Recent studies have shown that cryptic speciation is common in cephalopods, including several oceanic squids formerly considered ‘cosmopolitan species.’ Further efforts are needed to investigate the cryptic diversity of commercial sp...

Synopsis Cryptic species complexes represent an important challenge for the adequate characterization of Earth’s biodiversity. Oceanic organisms tend to have greater unrecognized cryptic biodiversity since the marine realm was often considered to lack hard barriers to genetic exchange. Here, we tested the effect of several Atlantic and Mediterranea...

Synopsis Few animal groups can claim the level of wonder that cephalopods instill in the minds of researchers and the general public. Much of cephalopod biology, however, remains unexplored: the largest invertebrate brain, difficult husbandry conditions, and complex (meta-)genomes, among many other things, have hindered progress in addressing key q...

Light organs (LO) with symbiotic bioluminescent bacteria are hallmarks of many bobtail squid species. These organs possess structural and functional features to modulate light, analogous to those found in coleoid eyes. Previous studies identified four transcription factors and modulators (SIX, EYA, PAX6, DAC) associated with both eyes and light org...

Cephalopod research remains limited by the inability to culture species under laboratory conditions for multiple generations to provide continuous access to animals at all stages of the life cycle. Here, we describe a multi-generational laboratory culture system for two emerging cephalopod models: the hummingbird or Berry’s bobtail squid, Euprymna...

Cephalopods are known for their large nervous systems, complex behaviors and morphological innovations. To investigate the genomic underpinnings of these features, we assembled the chromosomes of the Boston market squid, Doryteuthis (Loligo) pealeii, and the California two-spot octopus, Octopus bimaculoides , and compared them with those of the Haw...

Historically, marine oceanic open environments have been considered without barriers to dispersal, and the subsequent speciation of lineages present in distant areas. As a consequence, many marine pelagic invertebrates are considered as monotypic cosmopolitan taxa. However, this view has been consistently challenged in the last decades by the disco...

The Humboldt Current System (HCS) is characterised by latitudinal upwelling differences and interannual El Niño events that bring equatorial warm waters into the system. Within the HCS, the silverside Odontesthes regia is a coastal fish that faces intense harvesting, and physical and oceanographic variability. Here, we evaluated how different proce...

Cephalopods have recently moved into the research focus due to the growing number of sequenced genomes, molecular tools, and laboratory culture (Albertin & Simakov, 2020)⁠. Genome data now allows us to ask how the many known novelties of cephalopod morphology are reflected in their genomes and gene regulation. A crucial gap in this understanding ha...

Bobtail and bottletail squid are small cephalopods with striking anti-predatory defensive mechanisms, bioluminescence, and complex morphology; that inhabit nektobenthic and pelagic environments around the world’s oceans. Yet, the evolution and diversification of these animals remain unclear. Here, we used shallow genome sequencing of thirty-two bob...

Understanding the anthropogenic impact of oyster farms is essential for the management and conservation of marine fishes. In Japan, Hiroshima Bay is the region with the most intense oyster farming and thus suitable to study the impact of these farms. Here, we surveyed spherical planktonic eggs of the black sea bream Acanthopagrus schlegelii, one of...

The black sea bream Acanthopagrus schlegelii (Bleeker, 1854) is a commercially important species in Japanese waters. Assessing its population structure is essential to ensure its sustainability. In the Northwestern Pacific, historical glacial and interglacial periods during the Pleistocene have shaped the population structure of many coastal marine...

Assessing the distribution and diversity of cephalopods using traditional approaches (standard fishing, market collection, and DNA barcoding) is time-consuming. Environmental DNA (eDNA) assays are non-invasive, fast, and can capture the diversity of the species of interest using a specific primer-set. For Cephalopods, standardization of such primer...

Assessing the distribution and diversity of cephalopods using traditional approaches (standard fishing, market collection, and DNA barcoding) is time-consuming. Environmental DNA (eDNA) assays are non-invasive, fast, and can capture the diversity of the species of interest using a specific primer-set. For Cephalopods, standardization of such primer...

In Hiroshima Bay, parasitic isopods of the genus Mothocya infest the black sea bream Acanthopagrus schlegelii (Bleeker, 1854) and the Japanese halfbeak Hyporhamphus sajori (Temminck and Schlegel, 1846), two fish species that are abundant and commercially important in the Seto Inland Sea of Japan. Immature and mature Mothocya individuals can infect...

Dosidicus gigas is an economically important species distributed in the Eastern Pacific Ocean. Unraveling the genetic population structure of this species is crucial to ensure its fishery sustainability and management. Mitochondrial DNA sequences and nuclear neutral loci are useful to understand how historical and contemporary factors drive the gen...

We aimed to determine the spawning period of black sea bream Acanthopagrus schlegelii in Hiroshima Bay, Japan, based on the distribution of its eggs, to assist in the resource management of this species. We developed a monoclonal antibody assay for the identification of black sea bream eggs, and appraised its specificity using immunohistochemical s...

We evaluated the influence of areas with dissimilar upwelling intensity along the Humboldt Current System on the morphological variation of the economically important sea silverside Odontesthes regia by using geometric morphometric (GM) and meristic data of populations sampled off Northern Peru, Central Peru, Southern Peru-Northern Chile, and Centr...

Bobtail squid are emerging models for host–microbe interactions, behavior, and development, yet their species diversity and distribution remain poorly characterized. Here, we combine mitochondrial and transcriptome sequences with morphological analysis to describe three species of bobtail squid (Sepiolidae: Sepiolinae) from the Ryukyu archipelago,...

Comprising more than 800 extant species, the class Cephalopoda (octopuses, squid, cuttlefish, and nautiluses) is a fascinating group of marine conchiferan mollusks. Recently, the first cephalopod genome (of Octopus bimaculoides ) was published, providing a genomic framework, which will enable more detailed investigations of cephalopod characteristi...

The relative contribution of Sepioteuthis sp. 1 and Sepioteuthis sp. 2 to oval squid fishery stocks in western Japan was examined using microsatellite DNA and partial sequences of mitochondrial cytochrome oxidase subunit I. A total of 1718 Sepioteuthis spp. individuals from 19 populations were identified to determine the proportion of each species...

The present study seeks to incorporate a highly variable DNA barcode marker, additional to the standard regions of the cytochrome oxidase I gene and the 3′ end of the 16S large ribosomal subunit (16S rRNA), for a more effective species-level identification among cephalopods. Thus, we evaluated whether the 5′ end region of the 16S rRNA gene can be s...

The level of genetic diversity and population differentiation of oval squid Shiro-ika Sepioteuthis sp. 2 around mainland Japan were examined using highly polymorphic DNA markers. Ten microsatellite loci showed relatively low genetic diversity (average observed heterozygosity H O = 0.68, overall mean number of alleles N A = 10.0) as compared with ot...