Pygoluciola Wittmer 1939

Figs 38, 41−43, 50, 51, 364−462

Pygoluciola Wittmer 1939: 21. Ballantyne 2008: 1. Ballantyne & Lambkin 2006: 21; 2009: 107; 2013: 108. Ballantyne Lambkin Boontop et al. 2015: 8. Ballantyne Lambkin Luan et al. 2016: 204. Fu & Ballantyne 2008: 1. Fu Ballantyne & Lambkin 2010: 2; 2012: 6. Wattanachaiyingcharoen & Nak-Eiam 2012: 24. Yiu 2017: 105.

Luciola subgenus Pygoluciola (Wittmer). McDermott 1966: 115; Ballantyne 1968: 119; Ballantyne & Lambkin 2000: 82; 2001: 361; Ballantyne & McLean 1970: 233.

Type species. Pygoluciola stylifer Wittmer 1939, by monotypy (RMNH).

Diagnosis. Repeated with slight modification from Nada & Ballantyne (2018). Many Pygoluciola are difficult to diagnose to genus using only external morphology and may require dissection. All species of Pygoluciola have a similar distinctive pattern of aedeagal sheath and aedeagus: the aedeagal sheath has an elongate narrow sternite which extends well beyond the lateral tergite articulations and may bear paired lobes at its apex (four species have the sheath sternite terminated by a boomerang shaped lobe). The aedeagal LL are divisible into two sections, a basal well sclerotized portion which has an asymmetrical anterior margin and a short median dorsal separation, and an apical portion which is membranous and elongated usually well beyond the rounded apex of the median lobe.

Using only external morphology, Pygoluciola exists in at least three different forms which can be diagnosed individually:

1. The form described originally by Wittmer (1939) has V7 with a median posterior prolongation which often curves dorsally, and may be engulfed by a similar prolongation of the midposterior margin of T8, which curves ventrally.

2. In P. dunguna Nada and P. tamarat Jusoh sp. nov. the median posterior margin of V7 is prolonged and inclines slightly upward where the tip of the MPP abuts against the underside of the narrow T8.

3. In both P. phupan sp. nov. and P. qingyu (Fu et Ballantyne) there is no MPP and the posterior margin of V7 is evenly rounded; the posterior margin of T 8 in both is slightly downturned, narrowly in P. qingyu (at right angles to the longitudinal axis of the body), more well defined in P. phupan sp. nov.

LOs in V7 are often retracted from the lateral and posterior margins and these lateral margins may be uprolled. T8 is always narrower than T7, often with parallel sides, elongate slender anterolateral prolongations, and entire posterior margin; dorsoventral muscles joining the lateral margins of T7 to the ventrite below create depressed areas at the sides of T7. Known females are macropterous and bursa plates appear to be hooked with a single point of attachment to the inside walls of the bursa and up to three points of irregular length which incline in an anterior, posterior and inner direction. Larvae associated by breeding for P. qingyu only are terrestrial with strong well sclerotized dorsal plates, and mandibles with two inner teeth. Larvae associated with catches of adult P. dunguna may be riparian or even aquatic, having many blunt spines arising from the margins of all tergal plates but the terminal one. They also have mandibles with two inner teeth.

Remarks. Wittmer (1939) described the genus Pygoluciola from only one species Pygoluciola hamulata Wittmer, having pronounced modifications of the terminal abdomen where both the median posterior areas of V7 and T8 are prolonged and may incline, V7 dorsally and T8 ventrally, and in dried pinned specimens they may envelop each other. Pygoluciola was submerged under the genus Luciola by McDermott (1966) and treated as a subgenus by Ballantyne (1968) and Ballantyne & Lambkin (2001), until Ballantyne & Lambkin (2006) reassigned it to generic status. Subsequently Ballantyne (1968), Ballantyne & Lambkin (2001, 2006), and Ballantyne (2008) described five more species.

Pygoluciola Wittmer was thought to be a rare genus as it was poorly represented in collections (Ballantyne 2008; Ballantyne & Lambkin 2001, 2006). We now know that it exists in several forms as described above. The first as described by Wittmer (1939) is the rarer form, and consists of six species (see Table 24) which are easily recognised by the modifications to the terminal abdomen in males;

Fu & Ballantyne (2008) first realised that Pygoluciola could exist in a second form where the pronounced abdominal modifications described above did not exist. Species having this form are only recognisable on dissection, where the typical Pygoluciola patterns of genitalia are seen: aedeagus with LL considerably longer than ML and membranous in their apical half; basal portion of LL well sclerotised and not fused along all of their dorsal length; aedeagal sheath symmetrical, with narrow elongated anterior portion of sheath sternite expanding in its posterior area and often terminated by paired lobes; lateral arms of tergite of sheath visible beside the sheath sternite. Fu and Ballantyne (2008) described a distinctively coloured species from China as P. qingyu. Nak-Eiam in Thailand has discovered several species with similar genitalic characters to P. qingyu, and it seems that Pygoluciola is much more widespread than previously thought (Nak-Eiam 2015). Wattanachaiyingcharoen & Nak-Eiam (2012) distinguished mainland (Asian) species and island (Borneo and Mindanao) and indicated that the pronounced terminal abdomen modifications seemed to be characteristic of the island species. They felt the long separation of the mainland and islands mentioned may have led to the separation of the different forms of this genus. Fu (2014: 65, 67, 68) identified three possible Pygoluciola sp. from China which will be addressed elsewhere. He associated a larva for the unidentified species on page 65, and listed as ‘ Luciola sp.’ on page 46 a species which we would assign to Pygoluciola, it having the ‘boomerang’ shaped piece at the posterior end of the aedeagal sheath sternite. Of the four species we characterise here with that feature, three have pale margined elytra, while the dorsal colour of the fourth, P. abscondita comb. nov., is much paler than that illustrated by Fu.