Blochius Explained

Blochius is an extinct genus of prehistoric billfish from the Eocene. It is only known from the Monte Bolca deposits in Italy, and was likely restricted to shallow, tropical waters of the Tethys Sea.^{[1] [2]}

Discovery

The existence of Blochius was known as early as 1709, where it is mentioned in a written account by Johann Jakob Scheuchzer, who identified a fragment of a Blochius skeleton and identified it as being either related to the Xiphias (swordfish) or Siluro (catfish). It was not until the advent of Linnean taxonomy that it properly received a scientific name by Giovanni Serafino Volta, who named Blochius in 1796 after pioneering ichthyologist Marcus Elieser Bloch.

Taxonomy

It is one of two known definite genera in the family Blochiidae, alongside Loancorhynchus from earlier in the Eocene of Chile.^[3] The indeterminate remains of a Blochius-like fish are known from the Late Paleocene of Peru.^[4] Indeterminate blochiid remains are also known from the middle Eocene of Uzbekistan, and from the latest Paleocene/earliest Eocene Danata Formation of Turkmenistan.^{[5] [6]} Other potential blochiids such as Acestrus, Aglyptorhynchus, Hemirhabdorhynchus, Cylindracanthus and Congorhynchus are based on highly fragmentary remains and it is thus uncertain if they are blochiids, or even billfish for the last two.^{[7] [8]} Some authorities have found the Blochiidae to be basal billfish not closely related to any extant groups, whereas others find them to be more closely related to swordfish (Xiphiidae) than to marlins & sailfish (Istiophoridae).^[9] The following species are known, all from Italy:

• Blochius longirostris Volta, 1796
• Blochius macropterus de Zigno, 1887
• Blochius moorheadi Eastman, 1911 (nomen dubium)

Description

Blochius had a very slender elongated body, a narrow head with elongated upper and lower jaws and large eyes. Much like its modern relatives such as swordfish, it had an elongated rostrum.^[10] Although generally small in size at around 2 feet in length, it could reach a maximum length of 2.155m (07.07feet). The rostrum generally comprised 40% of the body length.^[11] It likely hunted in a manner similar to modern needlefish.

Bibliography

• G. S. Volta, Ittiolitologia Veronese del museo Bozziano ora annesso a quello del conte Giovambattista Gazola e di altri gabinetti fossili veronesi con la versione latina, Stamperia Guiliari, Verona, 1796–1808, 323 pp.
• C. R. Eastman, Catalog of fishes in the Carnegie Museum. Part 1. Fishes from the Upper Eocene of monte Bolca. Mem. Carnegie Mus., Pittsburgh 4, 1911. pp. 349–391.
• W. Landini e L. Sorbini. 1996. Ecological and trophic relationships of Eocene monte Bolca (Pesciara) fish fauna, pp 105–112 in A. Cherchi, ed. Autoecology of selected fossil organisms: achievements and problems. Boll. soc. Paleo. Italiana spec 3.
• H. L. Fierstine e K. A. Monsch. 2002. Redescription and phylogenetic relationships of the Family Blochiidae (Perciformes: Scombroidei), middle Eocene, monte Bolca, Italy. Miscellanea Paleontologica, studi e ricerche sui giacimenti terziari di Bolca, mus. civico storia nat. Verona 9: 121–163.
• H. L. Fierstine, 2006. Fossil history of billfishes (Xiphioidei). Bull. Mar. Sci., 79(3): 433–453.

References

• Blochius, Paleobiology Database
• Harry L. Fierstine: Fossil History of Billfishes (Xiphioidei). Bulletin of Marine Science, Volume 79, Issue 3, January 2006, Seiten 433-453 Abstract
• Karl Albert Frickhinger: Fossilien Atlas Fische, Mergus-Verlag, Melle, 1999,

Notes and References

1. Web site: PBDB . 2024-03-19 . paleobiodb.org.
2. Fierstine . Harry L. . 2006-11-01 . Fossil history of billfishes (Xiphioidei) . Bulletin of Marine Science . 79 . 3 . 433–453.
3. Otero . Rodrigo A. . 2019 . Loancorhynchus catrillancai gen. et sp. nov., a new swordfish (Xiphioidei, Blochiidae) from the Middle Eocene of central Chile . PeerJ . 7 . e6671 . 10.7717/peerj.6671 . free . 2167-8359 . 6440463 . 30941278.
4. Friedman . Matt . V. Andrews . James . Saad . Hadeel . El-Sayed . Sanaa . 2023-06-16 . The Cretaceous–Paleogene transition in spiny-rayed fishes: surveying "Patterson's Gap" in the acanthomorph skeletal record André Dumont medalist lecture 2018 . Geologica Belgica . en . 10.20341/gb.2023.002 . 1374-8505. free .
5. Web site: PBDB . 2024-03-19 . paleobiodb.org.
6. Monsch . Kenneth A. . Bannikov . Alexandre F. . 2011 . New taxonomic synopses and revision of the scombroid fishes (Scombroidei, Perciformes), including billfishes, from the Cenozoic of territories of the former USSR . Earth and Environmental Science Transactions of the Royal Society of Edinburgh . en . 102 . 4 . 253–300 . 2011EESTR.102..253M . 10.1017/S1755691011010085 . 1755-6910 . 129577132.
7. Parris, D. C., Grandstaff, B. S. and Bell, G. L. 2001. Reassessment of the affinities of the extinct genus Cylindracanthus (Osteichthyes). Proceedings of the South Dakota Academy of Science, 80: 161–172.
8. Fierstine . Harry L. . Monsch . Kenneth A. . 2002 . Redescription and phylogenetic relationships of the family Blochiidae (Perciformes: Scombroidei), Middle Eocene, Monte Bolca, Italy . Studie Ricerchesui Giacimenti Terziari di Bolca, Museo Civico di Storia Naturale di Verona . 9 . 121–163.
9. Near . Thomas J . Thacker . Christine E . 18 April 2024 . Phylogenetic classification of living and fossil ray-finned fishes (Actinopterygii) . Bulletin of the Peabody Museum of Natural History . 65 . 10.3374/014.065.0101 . free.
10. De Gracia . Carlos . Correa-Metrio . Alex . Carvalho . Mónica . Velez-Juarbe . Jorge . Přikryl . Tomáš . Jaramillo . Carlos . Kriwet . Jürgen . 2022-12-31 . Towards a unifying systematic scheme of fossil and living billfishes (Teleostei, Istiophoridae) . Journal of Systematic Palaeontology . en . 20 . 1 . 1–36 . 10.1080/14772019.2022.2091959 . 2022JSPal..20....1D . 1477-2019.
11. Book: Ellis, Richard . Swordfish . 2013 . University of Chicago Press . 10.7208/chicago/9780226922928.001.0001 . 978-0-226-92290-4.