428 
THE CORAL TRIANGLE: HEARST BIODIVERSITY EXPEDITION 
Papuan archipelago (Hoffman 1980, 1982, 2001). Members of the Platyrhacidae are distinguished 
by having wide discoid peritreme around their lateral ozopores, wide epiproct, setae tuft on the 
labmm and enlarged and elevated tracheal spiracles. 
Male and female genitalia of Platyrhacidae follow the pattern of Polydesmida. The l ^^ leg pair 
of the 1^^ body ring of males is modified into the gonopods, and the 2 ^^^ jeg pair carries a simple 
gonopore ventrally on each coxa. Females carry a single genital opening ventrally between the ster- 
nite of the 2^^^ body ring, which support the 2^^^ leg pair, and the ring formed by the pleurites of the 
body ring. The anterior ventral margin of this ring is called the epigyne. However, Platyrhaci¬ 
dae male gonopod ai*e distinguished from other Polydesmida families by lacking additional 
processes on the coxae and prefemora, and by having in its terminal section, the acropodite, a slen¬ 
der solenomere and a large process, traditionally labeled tibiotarsus (see Hoffman 2011:405). 
Gervais (1836) described margaritiferus (Gervais, 1836) in the genus Polydesmus 
Latreille, 1803, based on a female specimen from Manila, Luzon Province, Philippines. Peters 
(1864:544, species 68) considered meyenii Brandt, 1839 and Platyrhacus fuscus Koch, 
1987 (with question mark) as a junior synonyms of /. margaritiferus. Attems (1899) transferred 
/. margaritiferus to the genus Platyrhacus Koch, 1847 in the subgenus Platyrhacus, and 
redescribed P fuscus in the subgenus Haplorhacus Attems 1914. Later, Attems (1938) synony- 
mized Platyrhacus philippinorum Chamberlin, 1921 with /. margaritiferus based on at least a male 
specimen. He described the gonopod having the tibiotarsus pointed and toothed laterally (“[...] 
jagged knife blade”), and the solenomere with more than one curve (“[...] curved and hooked at 
the end”) (Attems 1899, fig. 341; Attems 1838, fig. 249). 
Wang (1951) made a key with illusffations to discriminate between Philippine species of 
Platyrhacus, including P. philippinorum and /. margaritiferus. He described the gonopod of 
P. philippinorum having the tibiotarsus pointed and toothed laterally, and the solenomere with more 
than one curve (“[...] acute tip of solenomerere curved”) (Wang 1951, fig. 71), and P. margari¬ 
tiferus, contrary to Attems (1938), having the tibiotarsus without tooth and the solenomere with one 
curve (“[...] lacks a secondary curvature”) (Wang 1951, fig. 73). Wang (1951) never took formal 
action to elevate P. philippinorum to species level, despite the differences he found between 
P. philippinorum and /. margaritiferus. Since Wang (1951) never cited the work of Attems (1938), 
we assume that Wang may not have been aware of the synonymy proposed by Attems (1938). Fur¬ 
thermore, Wang (1951) revised several females and males of 1. margaritiferus from the type local¬ 
ity and designated them as plesiotypes (i.e., topotypes), but he never had access to the material used 
by Gervais, Karsch and Attems. The evidence suggests that the species that Wang (1951) re¬ 
described and illustrated as P. philippinorum is actually /. margaritiferus, and the one that he re¬ 
described as I. margaritiferus is not conspecific, but instead represents a new or an aheady known 
species. The nomenclatural action and the taxonomic revision of the former species are beyond the 
scope of this conti'ibution. 
Jeekel (2007) transferred two species from Platyrhacus to Ilodesmus Cook, 1896 namely, 
Ilodesmus bakeri (Wang, 1951) and/, margaritiferus, in his Catalog of Indo-Australian Platyrhaci¬ 
dae (Jeekel, 2007). Ilodesmus meyenii (Brandt, 1839) remains the type species of the genus, even 
if it turns out to be a junior synonym. Peters (1864) synonymized /. margaritiferus and 1. meyenii. 
Since Cook (1896) never cited the publication of Peters (1864), we assume that Cook may not have 
been aware of the synonymy proposed by Peters (1864). Jeekel (2007) considered P. philippino¬ 
rum as a junior synonym of / margaritiferus (following Attems 1938), and I. meyenii and / mar¬ 
garitiferus as valid species, conhary to Peters (1864). In this contribution we exaitiined P. philip¬ 
pinorum and P meyenii male types, and confirm those species as junior synonyms of / margari¬ 
tiferus, as were considered by Attems (1938) and Peters (1894), respectively. 
