Pristosia dahud Morvan, 1994

Schmidt, Joachim & Hartmann, Matthias, 2009, Pristosia Motschulsky, 1865 from the Nepal Himalaya: Taxonomy and Biogeography (Coleoptera: Carabidae: Sphodrini), Zootaxa 2009, pp. 1-26 : 12-14

Pristosia dahud Morvan, 1994

Figs. 6–9 , 32–39 .

Type material: Holotypus female, with label data „ Nepala Breizh, Jumla XI.1987 P. Morvan“, „ Type “ ( CMORV).

Additional material: NEPAL: JUMLA DISTRICT: 12 males, 18 females, Khari Lagna, 3500–3700 m, 23.VI.–4.VII.1995, leg. D. Ahrens & H. Pommeranz ( CSCHM, NME); 2 males, 1 female, Khali Lagna Pass [= Khari Lagna], 3500 m, 16.–17.VI.1998, leg. W. Schawaller ( SMNS); 1 male, 10 km NNW Jumla, Bachtal N Khari La, 3500– 3200 m, 29°22’ N 82°09’ E, 20.VI.1999, leg. A. Weigel ( CWG); 1 male, Weg Jumla ü. Khari Lagna (Pass), 2600–3570 m, ca. 29°20’25 N 82°09’ 36E, 20.VI.1999, leg. E. Grill ( CGR); 1 male, 2 females, 12 km N Jumla, Bachtal N Khari La, 3280 m, 29°29’14 N 82°09’ 17E, 21.VI.1999, leg. A. Weigel ( NME, CWG); 1 male, 1 female, 25 km NE Jumla, Sisne Himal, Chauke Khare Khola, 4100m, 29°24N 82°24E, 4.VII.1999, leg. A. Weigel ( CWG, NME); 1 male, Lamri-Jumla, Uthu, Chaudabhise Khola, 2600– 2400m, 22.VI.1997, leg. A. Weigel ( CWG); 13 males, 9 females, Talphi 15 km NE, 3700–4200 m, 29°22’23 N 82°23’ 26E, 17.VI.1997, leg. A. Weigel ( CSCHM, CWG, NME); 20 males, 5 females, Talphi 15 km NE, Dhauli Lake, 4400 m, 17.VI.1997, leg. A. Weigel ( CSCHM, CWG, NME); 1 male, 1 female, Weg Lamri über Talphi, 2695–3725 m, 13.–16.VI.1997, 29°21N 82°23E, leg. E. Grill ( CSCHM, NME); 1 female, Lager N Maharigaon, 3200 mNN, Wald, Ufer, 29°20’25N, 82°23’16E, 07.–09.VII.1999, leg. Grill ( NME); 6 males, 4 females, 20 km NE Jumla, Hochebene 5 km N Maharigaon, 3700m, 29°21’23 N 82°23’ 41E, 06.VII.1999, leg. A. Weigel ( CWG, NME); 41 males, 29 females, Maharigaon, Hochalm, 3680–3850 m, 29°21’23 N 82°23’ 41E, 6.VII.1999, leg. E. Grill ( CGR, CSCHM, NME); 3 males, 2 females, Maharigaon, Aufstieg zum Dhauli Lake, 3725–4230 m, 29°22N 82°23E, 17.VI.1997, leg. E. Grill ( CSCHM); 1 male, 1 female, 25 km NE Jumla, Dhauli Lake, 4200m, 29°21N 82°23E, 05.VII.1999, leg. A. Weigel ( CWG, NME); 2 males, 10 females, Umg. Hochlager am Dhauli Lake, 3800–4400 m, 29°22’26 N 82°23’ 26E, 17.–18.VI.1997, leg. J. Weipert ( CWP, NME); 45 males, 32 females, Umg. Hochlager am Dhauli Lake, 18.VI.1997, 4200–4500 m, 29°22’26 N 82°23’ 26E, leg. J. Weipert ( CSCHM, CWP, NME); 1 male, Maharigaon, Pass am Dhauli Lake, 4230–4600 m, 29°22’26 N 82°23’ 26E, 18.VI.1997, leg. E. Grill ( CSCHM); 5 male, 4 female, Maharigaon N, Dhauli Lake, 4200–4600 m, 29°22’3 N 82°23’ 3E, 17.VI.1997, leg. M. Hartmann ( CSCHM, NME); 9 males, 6 female, Maharigaon N, Dhauli Lake, 4200–4500 m, 29°22 N 82°23’ 2E, 18.VI.1997, leg. M. Hartmann ( CSCHM, NME). MUGU DISTRICT: 1 male, Churchi Lagna, 3200–3400 m, 26.VI.–2.VII.1995, leg. D. Ahrens & H. Pommeranz ( CSCHM); 5 males, 1 female, SW Rara Lake, 3200 m, 12.VI.1998, leg. W. Schawaller, ( CSCHM, SMNS).

Redescription: 320 specimens studied.

Body length 10.5–12.0 mm.

Colour: Dorsal and ventral surface of body and femora black or almost black, knees, tibiae, tarsi, antennae and palpi reddish brown. Male dorsal surface shiny throughout; female shiny on head and pronotum but with elytra dull.

Microsculpture: Head with mesh pattern isodiametric, moderately engraved, and pronotum with very weakly engraved slightly transverse meshes, visible under high magnification (80x). Meshes of microsculpture on elytra in male weakly engraved, slightly transverse; in female isodiametric, much more deeply engraved and scale-like in anterior half, but weakly engraved and slightly transverse in posterior half.

Head: Temporae about 3/4 of eye diameter. Antennomeres I+II apart from primary apical setation each seldom with a very fine additional apical seta.

Pronotum: Usually more slender and almost as long as wide (ratio PW/PL 1.00–1.09, but in Khari Lagna population up to 1.14; PW/HW 1.37–1.47, in Khari Lagna population up to 1.52). Anterior margin somewhat smaller than base. Pronotal sides convexly rounded in anterior 2/3 but straight or slightly concave in posterior third ( Figs. 6, 7, 9 ), in Khari Lagna population sometimes slightly convex before base ( Fig. 8 ). Hind angles rounded. Base almost straight in middle, strongly bent anteriorly toward sides. Lateral gutter slightly, in Khari Lagna population sometimes more strongly expanded toward base. Basolateral seta located slightly distant (1–2 times pore diameter) from lateral edge, but distinctly distant (5–7 times pore diameter) from base.

Elytra: Slender oval, ratio EL/EW 1.58–1.72, EW/PW 1.50–1.52, usually distinctly narrowed toward shoulder, but in some specimens of Khari Lagna population with shoulders relatively broad. Basal groove moderately concave, forming a right angle with scutellar stria and an obtuse or rounded angle with lateral groove.

Legs: Relatively slender.

Male genitalia: Aedeagal median lobe usually of medium size ( Figs. 34–38 ), but large in some specimens of Khari Lagna population (see Figs. 32, 33 ), more strongly curved in basal half, straight on ventral surface toward apex (or distinctly convex in some specimens of Khari Lagna population), and with terminal bead slightly angular, seen laterally ( Figs. 33, 35 , 37, 39 ). Apical lamella relatively broad. In dorsal view, the internal sac longitudinal folds on both sides of ostium are connected with the transverse folding of median lobe middle ( Figs. 32, 34 , 36, 38 ).

Identification: P. dahud is very similar to P. g l a b e l l a sp. n. and P. s i m i l a t a sp. n., both from Far Western Nepal, but differs mainly in internal sac features of aedeagal median lobe; for more details see diagnosis of the two newly described species below. According to pronotal shape with rounded posterior angles P. dahud is also similar to P. leptodes Andrewes, 1934 , and P. brancuccii Deuve, Lassalle & Quéinnec, 1985 , from Kumaon Himalaya, but is easily differentiated from both of these species by lacking dorsal setiferous pores in interval III. P. a t re m a which also occurs in the Kumaon Himalaya has the same elytral chaetotaxy, but differs by having pronotal posterior angles almost rectangular, and by having a smaller aedeagus with terminal bead of apical lamella not protruded dorsally.

Distribution and geographical variation: Figs. 42 , 43 . Based on additional material from the adjacent southern mountains described below in detail, P. dahud seems to be a polytypic species. The nominotypical form is distributed in a relatively small area along the western slopes of the Sisne Himal, which is the westernmost part of the Kanjiroba massif, Western Nepal, between the Chaudabise Khola in the south and the Mugu Karnali river in the north. Specimens from the Khari Lagna range north of the Jumla place are of remarkably high variability in the pronotal shape and in the aedeagal median lobe shape and size. We were able to document specimens of one and the same population that possess pronotal and aedeagal characteristics of the forma typica ( Figs. 9 , 34, 35 ) as well as individuals that possess characters similar to the allopatric populations in the Gothichaur valley (see description of P. dahud polita ssp. n. below). Such specimens exhibit a broader pronotum with the sides slightly convex and rounded toward the base and the lateral gutter more expanded in the posterior half ( Fig. 8 ), as well as a larger median lobe with the ventral side distinctly convex ( Fig. 33 ). However, not a single female specimen has been found that possesses similar elytral microsculpture characteristics as found in specimens from the Gothichaur valley. Based on these morphological data we hypothesize that: (1) The Gothichaur populations have their own evolutionary history documented in at least one autapomorphic feature. (2) Gene flow has taken place from populations in the Gothichaur valley to those of the Khari Lagna range, which resulted in transitional characteristics in some individuals distributed in Khari Lagna. This exchange of genetic material could have occurred during glacial periods when the vertical distribution of Himalayan Nepalese Pristosia species was lower than presently found and the previously separated populations met temporarily in the Tila river valley. (3) Irrespective of the present allopatry, gene flow is considered to be potentially possible because distinct differences in male genital internal sac characters could not be discovered and the external male genital characters appear to be transitionally developed within the Khari Lagna population. These assumptions induced us to hypothesize that the Gothichaur populations also belong to P. dahud sensu lato, but to describe a taxon for the Gothichaur populations at the subspecies level.

Habitat: The species was found from the high montane zone to the lower alpine zone at altitudes from approximately 2600 to 4400 m. It prefers deciduous forests in lower altitudes and wet open mats in higher altitudes.

Figures

FIGURE 42. Distribution of Pristosia in Nepal and adjacent parts of the Himalaya.

FIGURE 43. Distribution of Pristosia in the Western Nepal Himalaya.

FIGURES 5 – 15. Pristosia spp., pronotum. Fig. 5, P. dahud polita ssp. n., Paratype, male. Fig. 6, P. dahud Morvan, 1994, non-type, male, Rara Lake. Fig. 7, P. dahud Morvan, 1994, non-type, male, Maharigaon. Fig. 8, P. dahud Morvan, 1994, non-type, male, Khari Lagna (transitional form). Fig. 9, P. dahud Morvan, 1994, non-type, male, Khari Lagna (typical form). Fig. 10, P. similata sp. n., Paratype, male. Fig. 11, P. glabella sp. n., Paratype, male. Fig. 12, P. amaroides (Putzeys, 1877), non-type, female, India, Darjeeling. Fig. 13, P. a t re m a (Andrewes, 1926), Holotype. Fig. 14, P. nepalensis sp. n., Paratype, male. Fig. 15, P. championi (Andrewes, 1934), Holotype. Scale bar = 2 mm.

FIGURES 30 – 35. Pristosia spp., aedeagal median lobe, dorsal view (Figs. 30, 32, 34) and left lateral view (Figs. 31, 33, 35, the internal sac is figured only in dorsal view). Figs. 30, 31, P. dahud polita ssp. n., Paratype. Figs. 32, 33, P. dahud Morvan, 1994, non-type, Khari Lagna (transitional form). Figs. 34, 35, P. dahud Morvan, 1994, non-type, Khari Lagna (typical form). Scale bar = 1 mm.

FIGURES 36 – 41. Pristosia spp., aedeagal median lobe, dorsal view (Figs. 36, 38, 40) and left lateral view (Figs. 37, 39, 41, the internal sac is figured only in dorsal view). Figs. 36, 37, P. dahud Morvan, 1994, non-type, Maharigaon. Figs. 38, 39, P. dahud Morvan, 1994, non-type, Rara Lake. Figs. 40, 41, P. glabella sp. n., Holotype. Scale bar = 1 mm.