The Lyria (Plicolyria) planicostata-complex
A brief historical outline is necessary in order to clarify the confusion that surrounds this taxonomic puzzle:
a) 1903. Lyria planicostata was first described by G. B. Sowerby III based on a damaged
and discoloured specimen at the British Museum, lacking precise data.
b) October 1975. Ladd discovered fossil specimens from the Pleistocene-Holocene in the New Hebrides. He named this species Lyria santoensis. Later comparison revealed a complete similarity to Lyria planicostata.
c) November 1975. T. C. Lan described a nearly identical species taken from Taiwanese waters under the name of Lyria taiwanica.
d) December 1975. A month later, Habe described the same species under the name of Lyria kawamurai.
e) In 1978 a number of specimens were discovered in Philippine waters, with specimens coming from Davao being identical to those previously listed, the others from Bohol being quite different. Kosuge named these two groups:
Lyria taiwanica forma davaoensis: identical to planicostata, Lyria taiwanica forma boholensis: different.

In fact, two kinds of shell emerge from these multiple descriptions:
Lyria planicostata and its synonyms: L. santoensis; L. taiwanica, L. kawamurai and
L. taiwanica forma davaoensis;
Lyria planicostata forma boholensis. They are considered by many to be conspecific. In reality, it appears that these two types must be recognized as two separate species by virtue of the constant conchological differences concerning two characteristics not linked among volutes: the form of the axial sculpture and the patterning.

The differences are of a remarkable stability regardless of geographical dispersion which is large: from Taiwan to Tonga Islands for Lyria planicostata, from the Philippines to New Caledonia for forma
boholensis. Even if true syntopy has not been found yet, their distributions clearly overlap. Though the Taiwanese specimens bear some light intermediate characteristics, there are no authentically doubtful specimens found throughout its wide geographical range, at least to our present knowledge.

Type locality: Not given by Sowerby.
Range: Extremely large, but fragmented into isolated zones at the moment: Taiwan, Davao, West of Arafura Sea (one dead specimen in MNHN Karubar-Expedition, 1991), Solomon Islands, New Hebrides (Pleistocene fossils from Santo Island and one live taken specimen in MNHN Musorstom 8-Expedition, 1994), Loyalty Islands (one live taken specimen in MNHN Musorstom 6-Expedition, 1990). This range follows the western border of the Pacific Plate. Habitat: Deep water between 150 and 300 m.

Description: Shell large, solid, elongate fusiform, measuring up to 110 mm with an average size of 80-90 mm. Protoconch very small, light beige with two smooth whorls. Spire high and pointed. Teleoconch of 8-9 convex whorls with a glossy surface sculptured by 13-15 strong wide axial ribs, leaving only a virtual intercostal space.
Aperture narrow, forming 0.55 of the total length. Outer lip thickened forming internally a lenticular callus. Columella almost straight bearing 9-11 prominent plaits, often equally spaced apart. Siphonal notch narrow and shallow. Background colour beige overlaid with a pattern of 20-26 spiral brown lines, dense, continuous, well defined, at times grouped in pairs, and of three conspicious spiral bands of brown markings: subsutural, on the mid body whorl sometimes coalescing, and anterior. Aperture whitish or light yellow.
Animal: Head and foot are yellowish striped by thick brown radiating lines, merging and forming a network.

Comparison: L. (P.) planicostata must be compared with the other Indo-Pacific Lyria with a minute protoconch:
L. (P.) boholensis is different, with its axial ribs thinner and keel-shaped, the different setting of the columellar plaits and an interrupted open pattern;
L. (L.) habei have a thin and light structure with a different pattern, and three strong columellar plaits only. Remarks: Quite frequent in Davao waters, where it is caught in tangle nets at 200 m deep, it is fished only occasionally elsewhere. For this species as for the next, a fairly extended distribution might favor the existence of local races. The small number of specimens collected outside the Philippines has not yet shown any noticeable geographic differences. Taiwanese specimens (forma taiwanica) seem to have a more open pattern whereas the Solomons specimens have spiral lines often grouped in pairs like in the Philippines. The difference remains slight if one compares specimens from Taiwan with those of the Loyalty Islands.

TYPE LOCALITY: The label on the holotype, the only known specimen, bears no locality data. RANGE: Unknown. HABITAT: Unknown. DIMENSIONS: Holotype length, 53.0 mm; maximum diame- ter, 22.5 mm; aperture length, 33.9 mm. SHELL DESCRIPTION: Shell is of medium size. It is fusiform and solid, with a moderately high, pointed spire. Protoconch has two smooth, turbinate whorls. Teleoconch has seven convex, axially ribbed whorls. There are 15 such ribs on the penultimate whorl of the holotype. There is no spiral sculpture. Suture is channeled. Aperture is not wide; it is elongate, attenuated anteriorly, about five-eighths the total length of the shell; the outer lip is slightly thickened. Si- phonal notch is narrow and shallow; fasciole indistinct. Columella is calloused. It is slightly concave, with three strong, unequal anterior plaits followed by a few lirae. Base color is yellowish, banded with numerous spiral lines. Mar-gin of the columella is conspicuously streaked with brown. ANIMAL AND RADULA: Unknown. REMARKS: Morphologically, this extremely rare species is closely related to Lyria beauii (Fischer and Bernardi, 1857). It differs from that taxon in that it has weaker, less numerous columellar plaits and a more attenuated anterior shape. When more specimens of each species become available for study (less than six specimens of beau and only one of planicostata are known), planicostata may prove to be a synonym of beauii.