≤78 % of cephalothorax volume
||Mammola S, Michalik P, Hebets EA, Isaia M. Record breaking achievements by spiders and the scientists who study them. PeerJ. 2017 Oct 315:e3972. doi: 10.7717/peerj.3972 p.17 5th paragraphPubMed ID29104823
||Quesada R. et al. 2011. The allometry of CNS size and consequences of miniaturization in orb-weaving and cleptoparasitic spiders. Arthropod Structure & Development 40(6):521–529 DOI 10.1016/j.asd.2011.07.002PubMed ID22036838
||Primary source abstract: "Allometric studies of the gross neuroanatomy of adults from nine species of spiders from six web-weaving families (Orbicularia), and nymphs from six of these species, show that very small spiders resemble other small animals in having disproportionately larger central nervous systems (CNSs) relative to body mass when compared with large-bodied forms."
||P.17 5th paragraph: "Largest central nervous system—Very small spiders. The internal anatomy has been studied in details in very few species, and thus it is difficult to assess which species has the largest—or the smallest—central nervous system (CNS). Recent allometric studies of the gross neuroanatomy of a number of spider species, [had] shown that very small spiders (including nymphal stages) have disproportionately larger CNSs relative to body mass when compared with large-bodied forms. In fact, the brains of small spiders may extend out of their body cavity into their walking legs (coxae) (see primary source, p. 526, f. 4). Accordingly, the relatively large CNS of very small spiders can occupy up to 78% of the cephalothorax volume (primary source)."