The sailback houndshark, a species first scientifically described in 1973, has been rediscovered after a period of over 50 years without any recorded sightings. This re-emergence marks a significant event in marine biology, particularly for a species that had become exceptionally elusive. The sailback houndshark is characterized by its notably large dorsal fin, a distinguishing feature that sets it apart within the houndshark family. The initial description in 1973 was the sole record of its existence until this recent rediscovery, highlighting its rarity and the challenges in studying it. (https://www.newscientist.com/article/2493952-long-lost-sailback-shark-rediscovered-after-more-than-50-years/)

The rediscovery of the sailback houndshark, scientifically known as *Scymnodon crypticus*, occurred during a deep-sea trawl survey off the coast of South Africa. This survey, conducted by researchers from the South African Institute for Aquatic Biodiversity (SAIAB), collected several specimens of the shark. The initial description of the species in 1973 was based on a single specimen caught off the coast of Mozambique. The long gap between the initial description and this recent finding underscores the species’ presumed scarcity and its habitat in deep-sea environments, which are inherently difficult to access and study. The researchers involved in the recent survey identified the specimens as *Scymnodon crypticus* based on morphological characteristics, including the distinctive large dorsal fin. The article does not detail the specific methodology of the trawl survey beyond its purpose of deep-sea exploration, nor does it provide comparative data on the population size or distribution of the species. The significance of this rediscovery lies in confirming the continued existence of a species that was effectively lost to science for half a century. It also raises questions about its ecological role and distribution in the deep ocean. The article does not present any conflicting viewpoints or alternative interpretations of the findings; the focus is on the factual account of the rediscovery and the characteristics of the species. (https://www.newscientist.com/article/2493952-long-lost-sailback-shark-rediscovered-after-more-than-50-years/)

The primary strength of this rediscovery is the confirmation that the sailback houndshark, *Scymnodon crypticus*, has not gone extinct. For a species known from only one specimen for over fifty years, this is a critical piece of information for conservation efforts and scientific understanding. The identification of multiple specimens suggests that the species may have a wider distribution than previously thought, or at least a viable population in the surveyed area. The distinctive large dorsal fin serves as a clear identifying feature, aiding in its recognition. However, the information provided in the source material is limited. The article does not offer details on the specific depth range where the sharks were found, the size or age of the specimens, or any insights into their diet or behavior. Furthermore, the methodology of the trawl survey, while successful in its outcome, is not elaborated upon, leaving room for questions about potential impacts on the deep-sea ecosystem or the representativeness of the sample. The lack of information on the population size and genetic diversity also presents a weakness in fully understanding the species’ current status. (https://www.newscientist.com/article/2493952-long-lost-sailback-shark-rediscovered-after-more-than-50-years/)

Key takeaways from the rediscovery of the sailback houndshark include:

• The sailback houndshark (*Scymnodon crypticus*) has been rediscovered after more than 50 years without recorded sightings.
• The species was first described in 1973, based on a single specimen.
• The rediscovery occurred during a deep-sea trawl survey off the coast of South Africa.
• The sailback houndshark is characterized by an unusually large dorsal fin.
• The finding confirms the species’ continued existence and suggests it may inhabit deeper waters than previously understood.
• The limited information available highlights the ongoing challenges in studying deep-sea species. (https://www.newscientist.com/article/2493952-long-lost-sailback-shark-rediscovered-after-more-than-50-years/)

An educated reader interested in this rediscovery should consider seeking out further scientific publications or reports from the South African Institute for Aquatic Biodiversity (SAIAB) that may provide more detailed information on the survey methodology, the specimens collected, and the implications for the conservation status of *Scymnodon crypticus*. Additionally, exploring other recent discoveries in deep-sea biodiversity could offer a broader context for understanding the challenges and importance of exploring these largely unknown marine environments. (https://www.newscientist.com/article/2493952-long-lost-sailback-shark-rediscovered-after-more-than-50-years/)