The swordfish (genus: Xiphias) enters the LRT
Xiphias gladius
is the extant swordfish, a large, fast, open seas predator.
The swordfish lacks facial bones
the barracuda retains as vestiges rimming the orbit. That’s why it does not nest with the barracuda, but between the barracuda and the clade of halibut + electric eel, which also lacks those post-orbital bones… given the present paltry number of fish presently tested by the large reptile tree (LRT, 1490 taxa, subset Fig. 6).
Even tiny post-hatchling swordfish
(Fig. 3) have a large sword-like rostrum… and a matching mandible that shortens relative to the rostrum with maturity.
The swordfish vertebral column
(Figs. 1, 4) has far fewer vertebrae than in deep ancestor taxa, like Amia. Eocene swordfish ancestors, like Blochius (Fig. 1), already have fewer, but more elongate vertebrae and also lack pelvic fins.
Xiphias gladius (Linneaus 1758; Gregory and Conrad 1937; up to 4.5m in length) is the extant swordfish, derived from a sister to the barracuda, Sphyraena. 1cm long hatchlings more closely resemble little barracudas,,, then they look like little sailfish… then they reduce the long dorsal fin, keeping the portion just posterior to the skull.
The sword-like rostrum
is not used to spear, but to slice and maim smaller fish traveling in dense schools. Larval swordfish feed on zooplankton including other fish larvae. Juvenile swordfish eat squid, fishes, and pelagic crustaceans.
Egg production in a phylogenetic and size context:
Small Amia females produce 2000–5000 eggs.
Larger Sphyaena females produce 5000–30,000 eggs.
Even larger Xiphia females produce up to 29 million eggs.
References
Gregory WK and Conrad GM 1937. The comparative anatomy of the swordfish (Xiphias) and the sailfish (Istiophorus). The American Museum Novitates, 952:1-25.
Linnaeus C 1758. Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata.
Linneaus C von 1766. Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio duodecima, reformata. pp. 1–532. Holmiæ. (Salvius)
wiki/Amia
wiki/Xiphias
wiki/Sphyraena
Source: https://pterosaurheresies.wordpress.com/2019/05/31/the-swordfish-genus-xiphias-enters-the-lrt/
Anyone can join.
Anyone can contribute.
Anyone can become informed about their world.
"United We Stand" Click Here To Create Your Personal Citizen Journalist Account Today, Be Sure To Invite Your Friends.
Please Help Support BeforeitsNews by trying our Natural Health Products below!
Order by Phone at 888-809-8385 or online at https://mitocopper.com M - F 9am to 5pm EST
Order by Phone at 866-388-7003 or online at https://www.herbanomic.com M - F 9am to 5pm EST
Order by Phone at 866-388-7003 or online at https://www.herbanomics.com M - F 9am to 5pm EST
Humic & Fulvic Trace Minerals Complex - Nature's most important supplement! Vivid Dreams again!
HNEX HydroNano EXtracellular Water - Improve immune system health and reduce inflammation.
Ultimate Clinical Potency Curcumin - Natural pain relief, reduce inflammation and so much more.
MitoCopper - Bioavailable Copper destroys pathogens and gives you more energy. (See Blood Video)
Oxy Powder - Natural Colon Cleanser! Cleans out toxic buildup with oxygen!
Nascent Iodine - Promotes detoxification, mental focus and thyroid health.
Smart Meter Cover - Reduces Smart Meter radiation by 96%! (See Video).