April 2025 — A newly identified fish species, Hypoplectrus espinosai, has been discovered in the biologically rich waters of the Gulf of Mexico, specifically in the Alacranes Reef located on the Campeche Bank. This groundbreaking discovery was made by an international team of marine scientists from the Leibniz Center for Tropical Marine Research (ZMT) in Germany, in collaboration with researchers from Mexico and Panama.
A New Member of the Hamlet Fish Group
The new species, Hypoplectrus espinosai, also known by its common name “Campeche Bank Hamlet”, belongs to the hamlet group (Hypoplectrus)—a family of small, colorful predatory reef fish that inhabit coral reefs across the Caribbean and northwestern Atlantic Ocean. These fish typically feed on smaller fish and invertebrates and are renowned for their distinct, genetically defined color patterns.
Currently, there are 18 recognized hamlet species, with seven discovered in just the past 14 years. This latest addition is notable for its average size of 11 cm and a unique black saddle marking on its caudal peduncle—the section connecting the tail fin to the body. This distinct black patch sets it apart from similar species like the Butter Hamlet (Hypoplectrus unicolor) and the Veracruz Hamlet (Hypoplectrus castroaguirrei).
How Was Hypoplectrus espinosai Discovered?
The discovery began when Alfonso Aguilar-Perera, a marine biologist from the Autonomous University of Yucatán, noticed a strikingly different hamlet while diving at the Alacranes Reef. Intrigued by its color pattern, he reached out to Oscar Puebla, lead researcher at ZMT and Professor at the University of Oldenburg, Germany.
Though the new species bore some resemblance to other known hamlets, it exhibited distinct morphological and genetic traits. To confirm the discovery, the team gathered a multidisciplinary group including:
- Ichthyologists from Mexico and Panama
- Bioinformatician Martin Helmkampf from ZMT
- Professional underwater photographers Allison and Carlos Estapé
Confirming a New Species Through Genetic Analysis
Utilizing advanced genomic sequencing and photographic evidence, the researchers compared the new species against known hamlet genomes. The genetic divergence confirmed that this was indeed a previously undocumented species.
Co-author Martin Helmkampf explained, “We had already sequenced genomes of several hamlets, including H. unicolor and H. castroaguirrei. The genetic data clearly indicated that this was a distinct new species.”
Further differentiation came from physical traits: the larger black saddle marking and the absence of the black eye mask, which is characteristic of the Veracruz hamlet.
Why Discovering New Hamlet Species Still Matters
Historically, many hamlet variants were considered color morphs of a single species. However, genetic research has now confirmed that these are distinct species, each contributing to our understanding of marine biodiversity and evolutionary processes.
“This discovery offers key insights into the genetic mechanisms behind rapid species diversification,” said Puebla. “It also underscores the importance of protecting reef habitats, which are often hotspots for endemic species.”
Honoring a Legacy in Ichthyology
The species name, Hypoplectrus espinosai, pays tribute to the late Héctor Salvador Espinosa Pérez (1954–2022), a respected Mexican ichthyologist and founder of the Mexican Ichthyological Society. He also served as curator of the Mexican National Fish Collection.
The common name “Campeche Bank Hamlet” highlights the species’ native range in the southwestern Gulf of Mexico, emphasizing the ecological value and conservation needs of the Campeche Bank reef system.
Citation:
Oscar Puebla et al. “Hypoplectrus espinosai sp. nov. (Teleostei: Serranidae): A new hamlet species from the coral reefs of the southwestern Gulf of Mexico.” Zootaxa, 2025. DOI: 10.11646/zootaxa.5618.4.3