Photinus (Paraphotinus) anisodrilus, Zaragoza-Caballero, Santiago, 2007

Zaragoza-Caballero, Santiago, 2007, A new species of Photinus (Coleoptera: Lampyridae: Photinini) from Jalisco, Mexico, with comments on intraspecific aedeagal variability and a key to the species of the subgenus Paraphotinus, Zootaxa 1437, pp. 61-67 : 62-65

Photinus (Paraphotinus) anisodrilus sp. nov.

( Figs. 1 –14)

Diagnosis. Epipleura subhorizontal, gradually narrowing towards the apex; elytra with creamy lateral and sutural margins; posterior edge of fourth sternum and complete seventh sternum yellowish; median lobe of the aedeagus without dorsobasal excrescences, expanded at the base and slightly longer than lateral lobes; shape and length of the ventral branches of lateral lobes variable; lateral lobes not covering the median lobe ventrally.

Description. Male. Length: 7.3 mm. Width: 2.4 mm. ( Fig. 1). Lateral and sutural edges of the elytra, pro- and mesocoxae, pro- and mesotrochanters, ventral side of the pro- and mesofemora, posterior edge of III and the entire VI ventrite (true abdominal segments IV and VII), and most part of the external area of the pronotum with a creamy color. Remainder of body dark brown. External area of pronotum with an anterior expanded dark and two lateral reddish, smaller spots. Luminous area on ventrites V and VI.

Head. Interocular space slightly concave; integument shiny, with silky pubescence; eyes considerably developed, semispherical, finely faceted, occupying nearly two-thirds of the head and 1.7X longer than wide. Interocular distance 0.57 mm; antennae filiform, narrow, flat and short, barely reaching the middle of the posterior coxae. Combined length of antennomeres two to four 0.72 mm; first antennomere as long as the third (0.5 mm), second almost half of the latter, fourth to eleventh similar in length. Frons vertical, pilose, 0.7 X longer than antennal pits; fronto-clypeal suture concave; clypeus transversal, short and with anterior edge blunt; mandibles falcate and short. Maxillary palpi with last segment cuneiform; labial palpi with last segment laminar and securiform.

Thorax. Pronotum semicircular, 1.3X wider than long, posterior angles obtuse, posterior edge nearly straight, disc convex, sides excavated, integument shiny and pilose, with wide, marginally located glandular pores. Scutellum spatulate, posterior edge blunt; integument shagreened, shiny and pilose, with mesonotal areas shiny. Elytra nearly parallel, 4.8X longer than wide apex blunt. Epipleura narrow, with surface convex, integument rugosely shagreen, with pilosity procumbent, and with glandular pores marginally located. Legs short, femur and tibia flat, first segment of metatarsus longer than the following two segments combined, claws simple.

Abdomen. Sternites V and VI as long as the previous, with stigmatiform punctures; posterior edge of sterna five, six and seven concave, sternite VII ogival. Medium lobe of aedeagus (Figs. 2–4) without dorsobasal excrescences; expanded basally, with medium-size terminal orifice, and flagellum not visible. Lateral lobes with apex blunt, lateral branch nearly parallel and slightly curved.

Female. Length 7.0 mm; width 1.8 mm. Similar to male. Basal antennomeres shorter than those of males. Eyes 1.25X longer than wide; interocular distance 0.65 mm. Luminescent apparatus comprising the middle line of ventrite V.

Holotype. Male. San Buenaventura, Jalisco 19° 47’ 614’’ N 104° 03’ 324’’W, 720 m; 2-VIII-1997, S. Zaragoza col.. Allotype. Female. Same location, 3-IV-1997, S. Zaragoza col. Paratypes: 149 with the following locations and dates: San Buenaventura, Jalisco 7-II-1997 (2 males), S. Zaragoza col.; San Buenaventura, Jalisco 8-II-1997 (1 male), S. Zaragoza col.; San Buenaventura, Jalisco 9-II-1997 (1 male), S. Zaragoza col.; Arroyo Los Yesos, Jalisco 19° 43’ 066’’ N; 104° 03’ 535’’ W, 900 m. 4-III-1997 (2 males), S. Zaragoza col; San Buenaventura, Jalisco 3-IV-1997 (9 males), S. Zaragoza col; San Buenaventura, Jalisco, 4-IV-1997 (2 males), S. Zaragoza col.; San Buenaventura, Jalisco 30-IV-1997 (17 males), S. Zaragoza col.; Amacuahutitlán, Jalisco 19° 48’ 426’’ N, 104° 01’ 882’’ W, 900 m. 2-V-1997 (18 males), Zaragoza col., (6 males), A. Soria col.; San Buenaventura, Jalisco 6-VI-1997 (2 males), S. Zaragoza col.; 7 VI-1997 (4 males), S. Zaragoza col.; (2 males) col. A. Soria; San Buenaventura, Jalisco 1-VII-1997 (23 males, 1 female) S. Zaragoza col., (7 males), A. Soria col.; Amacuahutitlán, Jalisco 3-VII-1997 (14 males) A. Soria col., (15 males), S. Zaragoza col.; Los Yesos, Jalisco 4-VII-1997 (13 males), S. Zaragoza col.; San Buenaventura, Jalisco 2-V 1II- 1997 (1 male), S. Zaragoza col.; San Buenaventura, Jalisco 31-V 1II-1997 (2 males), S. Zaragoza col.; San Buenaventura, Jalisco 1-IX-1997 (1 male) S. Zaragoza col., San Buenaventura, Jalisco 3-IX-1997 (1 male), S. Zaragoza col.; San Buenaventura, Jalisco 30-IX-1997 (6 males), S. Zaragoza col. All specimens are deposited in the National Collection of Insects (Colección Nacional de Insectos; CNIN), and the Instituto de Biología, Universidad Nacional Autónoma de México ( UNAM).

Phenology. The specimens examined of P. anisodrilus were collected from February to October, with two abundance peaks in May and July, corresponding to the dry and rainy season, respectively.

Photinus (Paraphotinus) anisodrilus Figs. 2–4. Dorsal, ventral and lateral view of the aedeagus. Figs. 5–14. Lateral views of the right paramere showing variability (ratio minimum-maximum Depth/Separation), (Figs. 5–6). Lateral view of the right parameres (ratio minimum-maximum WidthBranch/LengthBranch), (Figs. 7–8). Lateral view of the right parameres (ratio minimum-maximum WidthTotal/LengthTotal), (Figs. 9–10). Lateral view of the right parameral edges: rounded, hooked, truncated, irregular, (Figs. 11–14). Line = 0.5 mm.

Etymology. The specific name anisodrilus derives from the Greek words anisos = different and drilus = penis.

Va r ia ti o n. Adult males: Length 6.0– 8.5 mm; maximum width 1.8–2.8 mm; pronotum length 1.2–1.7 mm and width 1.6–2.3 mm; elytra length 8.0– 6.8 mm and width 0.9–1.4 mm; interocular distance 0.50–0.65 mm; length of second to fourth antennomeres 0.25–0.29 mm.

Remarks. Males of P. anisodrilus show, a remarkable variation in both the size and form of the parameres, especially the ventral branches and their posterior edges (Figs. 4–6, 11). Four basic types of posterior edges were identified: (i) a ‘rounded’ type, which was found in 58 specimens (Fig. 11); (ii) a second type, found in 4 specimens that possess an internal curved projection (Fig. 12); (iii) a ‘truncated’ type, observed in 44 specimens (Fig. 13); and (iv) an ‘irregular’ type, present in 23 specimens (Fig. 14).

Considerable variation in the ratios of different morphometric features taken for the parameres was observed. These ratios included depth/separation of the apical edges (D/S) (range = 0.277–0.875; mean= 0.552; Figs. 5–6, 15), width/length of the ventral branch (WB/LB) (range = 0.266–1.200; mean = 0.634; Figs. 7–8, 16), and total width/length (WT/LT) (range = 0.605–1.202; mean = 0.879; Figs. 9–10, 17). However, despite this variation, 12.5%, 10.2%, and 10.9% of the specimens have ratios of 0.7, 1.0, and 0.6 for the total width/length, width/length of the ventral branch, and the separation of the posterior edge between the branch and the apex, respectively. [Please standardize decimal accuracy figures. As a general principle calculated levels of accuracy should reflect the original measurement, so that calculated metrics should be rounded.

Photinus anisodrilus appears to be closely related to P. texanus Green , P. inmaculatus Green , P. cookii Green , P. marginellus LeConte and P. curtatus Green because all these species lack ventral branches in their parameres. Therefore, all these species should be placed in the subgenus Paraphotinus . A close morphological similarity between P. marginellus and P. curtatus was noted in Lloyd’s (1967) study, where the relationship between the separation and depth in the posterior edges of the right paramere was considered. The apex of the paramere of some specimens of P. anisodrilus is similar those of P. marginellus and P. curtatus . The D/ S ratio of the right paramere is also similar in P. anisodrilus , P. marginellus and P. curtatus : the minimum and maximum values in P. anisodrilus (0.277–0.875) are intermediate between the values shown by P. m a rg i n e l l u s (0.43–1.00) and P. curtatus : (0.19–0.57). The shape and length of the middle lobe in P. anisodrilus is more similar to that of P. m a rg i n e l l u s.

The conservative morphology of the aedeagus is a distinctive element that characterizes many species of arthropods, including lampyrids, as frequently mentioned (e.g., Green 1949, 1953, 1966; McDermott and Buck 1959). The intraspecific variability of the male reproductive system in sexual selection processes, on the other hand, has also been well documented in different groups of Coleoptera (e.g., Staphylinidae : Kistner 1966; Leiodidae : Peck 1984) and other arthropods (see Eberhard 1985 for a review of this topic), especially when considering the selective behavior of the female in isolated populations or in members of subspecific populations. The present study represents the first report of considerable intraspecific variability of the aedeagus in Photinus , and further work will clarify whether this is related to the sexual selection process in the species.