Plusioglyphiulus Silvestri, 1923

Genus Plusioglyphiulus Silvestri, 1923 View in CoL

TYPE SPECIES. — Glyphiulus cavernicolus Silvestri, 1923 , by monotypy [ type locality: Bidi Caves, Sarawak, Borneo].

DIAGNOSIS. — 1. Male legs 1 generally strongly reduced, but remaining parts enlarged; sternite with a single, high, median process, strongly unciform in adults, directed frontally and usually supplied with several strong setae at the base on frontal face; coxites usually subconical and setose; telopodites completely reduced, only rarely visible as a minute knob distomedially. This is one of the basic autapomorphies of the genus.

2. Male legs 2 usually strongly enlarged, flattened sagittally, densely hairy on caudal face; tarsus stout, shortened; penes slender, subconical, devoid of setae. This is another strong autapomorphy of the genus.

3. Male legs 3 usually with elongated coxae, but with shortened and compact telopodites. This is a weaker autapomorphy of the genus, since certain species in some other genera of Cambalopsidae show similar conditions.

4. Both collum and segment 2 often very strongly enlarged, as wide as segments of posterior third of body or nearly so, thus making postcollar constriction remarkably narrow. This is a strong autapomorphy of the genus.

5. Pleural regions of segments 2-4 conspicuously expanded ventrad. This is a weak autapomorphy, because several species from other genera of Cambalopsidae show similar conditions.

6. Ventral extensions of male segment 7 especially prominent, usually with ends turned abruptly caudad. This is a weak autapomorphy, because several species from other genera of Cambalopsidae show similar conditions.

7. Carinotaxy patterns of collum highly variable. Crests proper virtually never obliterated or reduced, very often subdivided into 2-4 parts, often with 1- 3 intercalary tubercles or short crests; usually 10 crests reaching anterior margin. This is a strong autapomorphy of the genus.

8. The typical carinotaxy pattern of the metaterga is 3/3+I/ i+3/3(4)/3+m/(m)/m+3/3(4)/3+I/i+3/3, thus reflecting the fact that all or most of the dorsal crests or tubercles are arranged in three transverse rows (except P. bedosae n. sp. and P. pallidior n. sp.). The middle transverse row in adults is sometimes not in line with the two other rows, being intercalary; this row seems to only be attained at or towards the onset of adulthood. The median crest is usually lower than others, never doubled anteriorly. This is a relatively weak autapomorphy, because some species from other genera (e.g., Glyphiulus bedosae Golovatch, Geoffroy, Mauriès & Van den Spiegel, 2007 ) also show three transverse rows of tubercles on the metaterga, whereas two rows seem to regularly occur in immature stadia of some Plusioglyphiulus species.

9. The anterior gonopods usually have a plate-like sternum or coxosternum, normally without a median outgrowth; coxites separate or contiguous medially, but never fused, each with one or two distinct processes; telopodites moveable, elongate, subcylindrical, lateral to caudolateral in position, 1-segmented, often curved and setose. This is a rather strong, but not absolute autapomorphy of the genus, because in many Cambalopsidae representing various genera the anterior gonopods look alike.

10. Posterior gonopods smaller than anterior ones, but usually elongated, not compressed; coxite normally showing an arm or its traces, a shelf-like structure on frontal face and a fovea subapically, devoid of the often plumose flagella that are so characteristic of Glyphiulus species. This seems to be a weak autapomorphy, since the variation range in posterior gonopod conformation in Plusioglyphiulus is unusually wide.

11. Clypeus with three teeth anteromedially, only seldom variable ( P. pallidior n. sp.). This is a typical condition occurring throughout Juliformia.

12. Promentum always well separated from eumentum.

SPECIES INCLUDED. — Below is a checklist of the species hitherto assigned to Plusioglyphiulus , arranged in alphabetical order (after Jeekel 2004).

1. Plusioglyphiulus boutini Mauriès, 1970 , described from near Kampong Trach, 10.554°N, 104.471°E, Kampot Province, Cambodia; still known only from the original description ( Mauriès 1970), incorporated in later reviews and the most recent key ( Hoffman 1977; Mauriès 1983). Listed as a cave-dweller from Cambodia ( Boutin 2001).

2. Plusioglyphiulus cavernicolus ( Silvestri, 1923) , type species, described as Glyphiulus ( Plusioglyphiulus) cavernicolus , from “Bidi Caves” ( Silvestri 1923), most probably neither in India nor in Ceylon ( contra Attems 1936; Mauriès 1970; Jeekel 1971), but near Bau, Sarawak, Borneo ( Hoffman 1977), which is at 01.333°N, 110.167°E. This species, which is still known only from the original description ( Silvestri 1923), was referred to Plusioglyphiulus by Mauriès (1970), and incorporated in later reviews and the most recent key ( Hoffman 1977; Mauriès 1983). Koilraj et al. (2000) studied the locomotor activity of a population claimed to represent Glyphiulus cavernicolus in a cave in the Samanar hill complex ( 09°58’N, 78°10’E), about 8 km southeast of the Madurai Kamaraj University campus, Madurai, India. However, the identity of their material is highly questionable.

Likewise, the recent records of P. cavernicolus in several other caves of Sarawak ( Decu et al. 2001) are also likely to be misleading (see below).

3. Plusioglyphiulus dubius ( Attems, 1938) , described as Glyphiulus dubius , from a single female collected at Angkor, 13.369°N, 103.863°E, Cambodia. Still known only from the original description ( Attems 1938). Transferred with doubts to Plusioglyphiulus by Mauriès (1970), incorporated in later reviews and in the latest key ( Hoffman 1977; Mauriès 1983).

4. Plusioglyphiulus grandicollis Hoffman, 1977 , described from Batu Caves, 03.171°N, 101.703°E, Kuala Lumpur, Selangor State, Malaysia; still known only from the original description, incorporated in the latest review and key ( Hoffman 1977; Mauriès 1983). Listed as a cave-dweller from Malaysia ( Decu et al. 2001). This species will be redescribed below based on new material.

5. Plusioglyphiulus macfarlanei Mauriès,1983 ,described from an unknown locality in Sabah, Borneo, Malaysia;still known only from the original description ( Mauriès 1983).