A book that I'm currently writing called Surge features [an enemy faction called the Degenerates that are heavily inspired](http://tvtropes.org/pmwiki/pmwiki.php/Main/FantasyCounterpartCulture) [by the Scythians](http://arkhamhaus.com/scythian-scouts.html) (Indo-Iranian horse nomads that ruled the Eurasian Steppes and Central Asia from the 10th century BCE to the 3rd century CE) and consists mostly of humans parasitized by a prehistoric endoparasite called Echidna (named after the Dracaena that gave birth to numerous monsters in Greek mythology), which parasitizes and radically alters the entire physiology of a wide variety of organisms from the phylum Chordata.

Parasitized humans are transformed into nocturnal humanoids that are facultative quadrupedals and divided into three distinct subspecies, [named after the sons of Hercules and Echidna](http://tvtropes.org/pmwiki/pmwiki.php/Main/ReligiousAndMythologicalThemeNaming) (all of which were ancestors of the Scythians):

- Agathyrsus (*Falhumanus clavapugnus*): Physically imposing and immensely strong Degenerates used mostly as shock troops, *cataphractii* and heavy infantry

- Gelonus (*Falhumanus tetrabrachius*): Lightly-built and four-armed Degenerates which act as scouts, light infantry and cavalry whose purpose is to advance beyond their own front lines for the intent of harassing enemies from afar

- Scythes (*Falhumanus sagittarius*): Four-eyed Degenerates that have excellent vision and are deployed as marksmen and mounted riflemen, who engage their targets at long range.

Because they are fighting a losing war against a shadowy multi-national black ops unit called *S.W.O.R.D* using cutting-edge military technology, the Degenerates are forced to engage in guerrilla and asymmetrical warfare against *S.W.O.R.D*. One such tactic involves Gelonians and Scythi (acting as mounted riflemen/grenadiers and light/normal cavalry) working together in anti-armour hunter-killer cells commanded by Agathyrsi *cataphractii* (heavily armored cavalry) for the purpose of ambushing armoured vehicles like armoured personnel carriers, tanks and scout cars utilizing melee weaponry and firearms outfitted with special attachments and high-calibre armour-piercing ammunition coated in *scythicon*. 

[In lieu of horses, the Degenerates use a variety of parasitised animals as mounts](http://tvtropes.org/pmwiki/pmwiki.php/Main/BeastOfBattle) and the mounts mostly used by Agathyrsi *cataphractii* are [mutated feral pigs designated](http://tvtropes.org/pmwiki/pmwiki.php/Main/FullBoarAction) [Phaea](http://www.theoi.com/Ther/HusKrommyon.html) and Agathyrsi ride these things using horned saddles similar to those used by the Sarmatians (Indo-Iranian horse nomads closely related to the Scythians) and leather loops as stirrups. 

This leaves me with two problems:

 

 -  How big would Phaea need to
   be in order to carry a fully armoured Agathyrsi *cataphract*
   ([wearing plate
   armour](https://periklisdeligiannis.files.wordpress.com/2016/06/cataphract2.jpg)
   or an [ankle-length cuirass with parapleuridia made of interlaced narrow plates](http://warfare.netau.net/WRG/AotMaPW-86-Saka_Cavalryman.jpg)), since Agathyrsi stand around 10 feet tall (3.0 meters) and weigh 272 kilograms (599.66 pounds)?
 - What sort of body structure would Phaea need to support the weight of a fully armoured Agathyrsi *cataphract*?