Lyrognathus achilles, West, Rick C. & Nunn, Steven C., 2010

West, Rick C. & Nunn, Steven C., 2010, A taxonomic revision of the tarantula spider genus Lyrognathus Pocock 1895 (Araneae, Theraphosidae), with notes on the Selenocosmiinae, Zootaxa 2362, pp. 1-43 : 11-19

Lyrognathus achilles sp. nov.

( Figs 13–44 , 114 )

Types: female holotype, S88049 ; male paratype S88050 ; 2 female paratypes S88047 and S88048 , Gunung Nibung (2°07' S, 112°00' E), Kotawaringin Barat, Borneo, Indonesia, col. H. Yanto, 2 Apr. 2009, QM.— examined.

Etymology: After the mythical Greek warrior of Homer’s poem, The Iliad, due to the unique tarsal scopula division: distinct proximal bald patch on ventral tarsi ( Fig. 19 ) this species displays.

Diagnosis: Differs from both L. crotalus and L. saltator in having intercheliceral pegs (not spines), and retrolateral basomedial cheliceral spines. Differs from L. robustus in the undivided scopula for the full length of metatarsi, third claw absent on tarsi IV and swollen distal lateral lobes of the spermathecae. Differs from L. lessunda sp. nov. in the absence of “mushroom cap” medial lobes of the spermathecae. Differs from L. fuscus sp. nov. in the more pronounced anterior maxillary lobe, distal cream/white leg segment bands, larger size, color and uniform retrolateral tibiae IV with a penicillate brush (grading distally in L. fuscus sp. nov.).

Description: Female holotype ( Fig. 13 ) with body length: 50.57.

Color (in life, Fig. 13 ): anteriorly orange/brown, grading medially to dark brown/black posteriorly and entirely, with distinct cream/white bands on all leg segments distally. Dorsal coxae, trochantera palest of all, light grey. Ventrally dark brown/black on sternum, coxae, with legs same as seen dorsally.

Carapace ( Fig. 15 ): length 21.45, width 13.8 (width across anterior edge 9.45). Fovea 2.71 wide, procurved, deep, smaller in width than OT. Distance from anterior carapace to fovea 13.7. Carapace with 4 discernible hair types (C1 to C4): type C1, long, needle-form pallids bordering carapace entirely (darker basally): type C2, short blunt-tipped, basally dark grading to distally pallid and cover entire carapace evenly, but reasonably sparse: type C3, short, thin wavy pallids, form basis of carapace mat: type C4 emerge from what resemble bothrial collars, long, distally spiniform, pallid and lie in uniform arrangement of (>5) along anterior edge of each radial groove, (>4) along anterior edge of each thoracic groove, (>5) along anterior edge of each sulcal groove, (>10) along anterior edge of each caput groove and line of>5 along medial caput ridge (between OT and fovea).>4 more located behind each side of OT, nearest median caput row.

Eyes ( Fig. 16 ): ocular tubercle; length 2.25, width 3.0. OT highest posteriorly behind AME, sloping gradually anteriorly. Anterior row transverse, posterior row recurved. Eyes in lengths/widths: AME: 0.71/ 0.70, ALE: 0.69/0.27, PLE: 0.49/0.25, PME: 0.46/0.27. Inter-ocular distances: AME–AME: 0.29, AME– ALE: 0.21, AME–PME: 0.18, ALE–ALE: 1.85, ALE–PME: 0.38, PME–PME: 1.51, PME–PLE: 0.19, PLE– PLE: 2.35, ALE–PLE: 0.26. OT hairs:>15 (C2) directly posterior to AME’s, 4–5 between PME and center of OT (directly behind each AME). 20 (C2) along median anterior OT surface. OT entirely covered in small, weak, pallid setae (C3), directionally pointing to center of OT, posteriorly and anteriorly. Lateral small pallids very sparse with no uniform direction/random pointing.

Chelicerae (left, Figs 24–28 ): length 9.8, width at base of each lobe 4.25 (at bases widest point, dorsally), height: 7.1. Ectal lyrate region a series of strikers (>95) in 8 horizontal rows ( Fig. 25 ). Strongest and longest strikers on lowest rows. Each striker very stout, blade or scimitar-shaped, with long filiform ends. Cheliceral teeth, 12,>65 basomesal teeth. Intercheliceral pegs (>9 larger,>28 smaller) in tight cluster on basodorsal surface, very stout, 1/3 as wide as long ( Fig. 28 ). On retrolateral cheliceral surface, basomedially, with small cluster of short but strong spiniform setae (>5) and 1 spine pointing distad ( Fig. 26 ). Surrounding these spines, notable patch of fine setae, dark, of medium length, blends into typical thicker pallid retrolateral cheliceral setae. Setae filiform, seem to emerge from hemispherical bases.

Maxillae ( Figs 17 , 29 ): prolaterally plano-convex, anterior lobe well pronounced, many cuspules (> 140) on inner basoventral surface. Lyra ( Figs 29, 30 ): bacilliform rods (>145) form a dense, ovoid patch on prolateral maxillary surface (2.85 long, 1.71 high), lowest row with up to>11 bacillae, longest rods medially in lowest row. Rods distally paddle-shaped (paddles up to 0.45 long, paddles with proximal gradation into shaft, extends for full shaft length) with short to medium length shafts (total rod length including paddles 0.69), largest rods with no distal blades. At widest point, lyrate patch 13 rows deep with smallest rods dorsally. Posterior end of patch truncate but rounded, anterior end rounded. Immediately above maxillary suture>45 elongated spines on anterior margin, rows disordered. Labium ( Fig. 18 ): length 2.51, width 3.35.

Many small cuspules (>560) along anterior 1/4 surface. Labium with 2 discernible hair types (L1, L2); type L1: long, reasonably dark spiniform, curving distally toward anterior, most concentrated along lateral borders. Setae clearly longest along anterior edge (>35); type L2: 1/2 length of L1, interspersed with L1 but darker, more needle-form.

Sternum ( Fig. 17 ): length 9.58, width 7.35, saddle-form; with 5 discernible hair types (S1 to S5): type S1, longest, thick, darker basally, becoming pallid distally, entirely over surface, sparse: type S2, elongate spiniforms, dark basally, distally pallid, on margins, most concentrated posteriorly: type S3, short spiniforms, entirely, sparse: type S4, short, thin pallids, form basis of mat: type S5 dark basally, but apically pallid, short and blunt tipped, entirely cover in sparse disordered arrangement. Posteriorly between left and right coxae IV, border highly acuminate, lateral points slightly acuminate. Sigilla ( Fig. 17 ): 3 pairs (not including labiosternal sigilla), posterior, large, right: length 1.38, width 0.75, left with length 1.35, width 0.65. Ovular, 1.76 apart, 1.65 to 1.7 from margin. Median pair, 1/2 size of posterior, similar shape and 0.7–1.0 of their length from sternal margin. Anterior pair large, as big as medials, somewhat obscured and border margin. Labiosternal sigilla largest, 1.6 times size of PSS.

Legs: formula (length); IV, I, II, III: (width); IV, III, I, II. Leg RF ~84.51. Leg lengths (fem., pat., tib., met., tar., total): palp: 9.46, 5.98, 6.74, 0.00, 5.75, 27.93. I: 13.21, 8.87, 9.98, 9.15, 5.34, 46.55. II: 11.64, 7.96, 8.48, 7.59, 5.22, 40.89. III: 9.64, 6.79, 6.78, 8.57, 5.01, 36.79. IV: 15.55, 8.44, 11.33, 14.16, 5.6, 55.08. Leg widths (fem., pat., tib., met., tar., total.): palp: 2.15, 2.71, 2.42, 0.00, 2.54, 9.82. I: 3.38, 3.37, 2.99, 2.34, 2.14, 14.22. II: 3.37, 3.26, 2.79, 2.35, 2.23, 14.00. III: 4.07, 3.57, 3.05, 2.33, 2.18, 15.20. IV: 4.08, 3.61, 4.05, 2.83, 2.49, 17.06.Tib. IV with strong retrolateral villous setal fringe, proximally to distally uniform–entire ( Fig. 20 ).

Scopula: met. and tar. I–III undivided, met. IV undivided, tar. IV ( Fig. 22 ) only partially divided proximally (by one row of sparse setae>5, nonexistent in distal 1/2). Met. I–IV, for full length.

Coxae: some small black thorns prolatero-dorsally, no thorns retrolaterally on I–IV. Coxae easily seen dorsally. Cox. I longest, ca. 1.2 times length of II. IV widest, as long as III, basally rectangular with rounded corners. Coxae with small ventral thorns prolaterally on I–IV. I–III ventrally with many long thick blunt setae proximally, pallid. No short black setae. IV with mixture of long thick blunt setae entirely, pallid intermixed with shorter thin pallid setae. Ventral surface of coxae I–IV gently sloping anteriorly. Retrolateral setation: I– III with median narrow light brush, IV entirely covered in short thin pallid setae. I–IV retrolaterally lack ventral ledge. Ventral measurements for coxae: palp–length 9.78, width 4.94; I–9.18, 4.16; II–7.53, 3.63; III– 6.24, 4.02; IV–7.53, 4.96. Trochantera: palp–length 2.85, width 2.9; I–3.31, 4.06; II–2.9, 3.88; III–3.26, 3.6; IV–4.14, 4.11.

Trichobothria: on all tarsi basal filiform field slightly wider than clavate field, merges evenly. Clavates on tar. I in distal 1/2 (very dark), long filiforms only in basal 2/3, shorter filiforms intermixed with clavates distally. Clavate extent on tar. II–IV cf. I, in distal 1/2. Shorter filiforms for length. Short epitrichobothrial field on I shorter than clavates, increasing in length proximally. Tarsal organ evident on legs II–IV under stereo microscope (up to x64), coniform without noticeable ridges. On tar. I, entire field 4.56 long and 1.32 wide distally, to 1.85 wide proximally. On tar. IV, field 4.78 long and 0.89 wide distally, increasing to 1.95 proximally. Metatarsi: trichobothrial field not evident laterally or proximally in any form. Tibia: on tib. I prolaterally and proximally, short, possibly clavate trichobothria noted (>8 per 0.25mm squared) in L-shaped patch 0.25 long, 1.25 wide, clearly pallid:>6 filiforms in semicircular pattern proximally to rest of patch. On tib. IV prolaterally and proximally, short dark clavates (>7 per 0.25mm squared) in patch 1.66 long, 0.22 wide distinct:>7 filiforms in semicircular pattern proximally to rest of patch.

Spines: met. I with 1 DV, met. II with 1 DV, 1 DPV, 1 DRV, met. III with 2 DV, 1DPV, 1 DRV, 1 DD, 1 DPL and met. IV with 2 DV, 1DPV, 1 DRV, 1 DD, 1 DPD.

Claws: unarmed paired claws on all legs. Reduced third claw absent on leg IV.

Abdomen ( Fig. 19 ): ovular, elongated, yellow brown (in alcohol); with 4 discernible hair types (A1 to A4): Dorsally with 3 hair types: type A1 long, dark blunt tipped, uniform: type A2 mid-length, also dark, but distally spiniform, unlike type A1: type A3 form dense mat, mid-length, uniformly dark, needle-form (some stand erect, some posteriorly, but share similar morphology). Longest hairs (type A1) more concentrated posteriorly toward spinnerets, point distad, but toward proximal region, hairs stand erect, medially curved (toward posterior). Ventral hair types almost same as dorsal, although type A2 and A3 more dense entirely. Type A4 hair in very dense patch, trapezoid, posterior of pedicel between median regions of cox. IV. Hairs of medium length, wavy and pallid. Between anterior pair of booklungs, setal mat uniform with rest of venter ( Fig. 19 ).

Genitalia ( Fig. 23 ): epigastric fold 6.51 wide. Spermathecae paired but not fused, separated by 0.8 (width including spermathecae 2.4), bilobular apically, each lobe with strong apical rounded appendages, lateral/ outer lobes distally swollen, ovular: lateral lobe distal widths 0.45 (left)–0.41 (right): medial lobe distal widths 0.26 (left)–0.27 (right), heavily sclerotized gradually transition to weakly sclerotized shafts proximally. Lobes apically swollen, lateral lobes (including shaft length) at 4/5 length to medials. Epigastic fold extends to ca. 2/ 3 length of spermathecal lobes.

Spinnerets: PMS: length 2.1, width (medially) 0.95. PLS: section lengths; basal 3.45, medial 1.45, apical 2.55. PLS section widths (medially); basal 1.78, medial 1.32, apical 0.85. Spinnerets with 2 discernible hair types (SP1, SP2): SP1 very short and distally blunt pallid, covers both pairs ventrally, second form (SP2), very similar but up to three times longer, dorsally on all segments.

Male paratype ( Fig. 14 , as in female except) with body length: 34.09.

Color (in life, Fig. 14 ): With brass sheen to dorsal carapace, coxae and trochantera hairs, also less distinct in color anteriorly to posteriorly, clearly paler distal leg segments (pat., tib., met., tar.).

Carapace ( Fig. 31 ): length 13.85, and width 13.1 (width across anterior edge 7.35). Fovea 1.68 wide, procurved, deep, narrower than OT. Distance from anterior carapace to fovea, 9.89. Carapace hair types as in female except C1, C2 and C4 are brass color, iridescent in alcohol. Eyes ( Fig. 32 ): ocular tubercle; length 1.75, width 2.43.

Chelicerae (right, Fig. 36 ): length 7.89, width at base of each lobe 3.35 (at bases widest point, dorsally). Ectal lyrate region a series of strikers (>95) in 8 horizontal rows. Cheliceral teeth, 12,>65 basomesal teeth. Intercheliceral pegs (>9 larger,>17 smaller) in tight cluster on basodorsal surface, pegs more elongate than in females ( Fig. 37 ).

Maxillae. Lyra ( Fig. 30 ): large number of bacilliform rods (>170) form dense, ovoid patch on prolateral surface (2.45 long, 1.35 high), with lowest row composing of>14 bacillae, longest rods in center of lowest row. Rods distally paddle-shaped (paddles to 0.24 long), total length including paddles to 0.41, largest with no distal blades. At widest point, lyrate patch 12 rows deep, smallest rods dorsally. Posterior end of patch truncate but rounded, anterior end widely rounded. Immediately above suture>35 spiniform setae on anterior margin in disordered rows. Labium ( Fig. 33 ): length 1.73, width 2.39. Many small cuspules (>420) along anterior 1/4 surface.

Sternum ( Fig. 35 ): length 6.34, width 5.53, saddle-form. Sigilla: 3 pairs, posterior large; right with length 0.89, width 0.43, left with length 0.88, width 0.41. Ovular, 1.67 apart, 1.12–1.18 from margin. Median pair 1/ 2 size of posterior, similar shape, 0.5–0.8 of their length from margin. Anterior pair large, as in female. Labiosternal sigilla largest, 1.6 times size of PSS.

Legs: formula (length); IV, I, II, III: (width); III, IV, I, II. Leg RF ~93.14. Leg lengths (fem., pat., tib., met., tar., total): palp: 8.83, 5.0, 6.77, 0.00, 2.13, 22.73. I: 12.25, 6.83, 10.93, 9.78, 5.26, 45.05. II: 10.66, 6.38, 8.54, 8.17, 4.88, 38.63. III: 8.51, 5.26, 6.72, 7.8, 4.27, 32.56. IV: 13.28, 6.84, 10.38, 12.68, 5.19, 48.37. Leg widths (fem., pat., tib., met., tar., total.): palp: 2.22, 1.92, 1.90, 0.00, 1.97, 8.01. I: 2.9, 2.53, 2.13, 1.52, 1.6, 10.68. II: 2.8, 2.56, 1.91, 1.35, 1.43, 10.05. III: 3.73, 2.7, 2.36, 1.55, 1.56, 11.9. IV: 2.75, 2.58, 2.39, 1.72, 1.77, 11.21. Tib. IV with retrolateral villous setal fringe, proximally to distally uniform, not as elongate or dense as in females. Ventral measurements for coxae: palp–length 5.41, width 2.57; I–5.89, 2.67; II–5.45, 2.67; III–3.89, 2.78; IV–5.1, 3.78. Trochantera: palp–length 2.57, width 2.1; I–3.34, 3.1; II–2.78, 2.54; III–2.43, 2.45; IV– 3.35, 2.93.

Genitalia: Palp ( Figs 38–40 ): tibia mildly incrassate, tapering distally. Cymbium bipartite, tegulum large. Lanceolate embolus slightly tapers distally, very little flaring, proximally emerges anterior to tegulum. Relative length of palpal tibia about three times length of embolus. Longitudinal keel present, distinct (embolus not terete), along entire length of embolus, twisted through 90° prolaterally distally ( Fig. 40 ).

Spinnerets: PMS: length 1.23, width (medially) 0.51. PLS: section lengths; basal 1.95, medial 1.25, apical 1.85. PLS section widths (medially); basal 1.12, medial 0.75, apical 0.55.

Distribution and natural history ( Figs 41–44 , 114 ): Known only from the type locality, Gunung Nibung, Kotawaringin Barat, Borneo, Indonesia. Little is known; however, L. achilles is a fossorial spider that lives in higher shaded tropical forests away from the riparian flood plains. Burrows were found only on sloped embankments amongst leaf litter and low vegetation and were formed in clay-like soil. A mature male was found in early April (H. Yanto, pers. comm.).

Figures

FIGURE 114. Records of Lyrognathus species in Southeast Asia. C. Senescall

FIGURES 13 – 14. 13. Lyrognathus achilles sp. nov. 13. Holotype female in life. 14. Paratype male in life. Photos: R. C. West.

FIGURES 15 – 19. Lyrognathus achilles sp. nov., holotype female: 15. Carapace, dorsal view. 16. Eyes, dorsal view. 17. Sternum, labium, maxillae and coxa, ventral view. 18. Labium, ventral view. 19. Abdomen, legs IV, ventral view. Scale bar = 10 mm for 15, 17, 19; 2 mm for 16, 18. Photos: S. C. Nunn.

FIGURES 20 – 23. Lyrognathus achilles sp. nov., holotype female: 20. Leg IV, dorsal view. 21. Leg IV, prolateral view. 22. Tar. IV, ventral view. 23. Spermathecae, dorsal view. Scale bar = 10 mm for 20, 21; 5 mm for 22; 2 mm for 23. Photos: S. C. Nunn.

FIGURES 24 – 28. Lyrognathus achilles sp. nov., paratype female QM S 88047: 24. Left chelicerae, retrolateral view. 25. Cheliceral strikers, ectal view. 26. Basomedial cheliceral spine, prolateral view. 27. Left chelicerae, prolateral view. 28. Intercheliceral pegs, prolateral view. Scale bar = 5 mm for 24, 25, 27; 1 mm for 26, 28. Photos: S. C. Nunn.

FIGURES 29 – 34. Lyrognathus achilles sp. nov., paratype female QM S 88047 for 29, L. achilles sp. nov. paratype male all others: 29. Left maxillae, prolateral view. 30. Right maxillae, prolateral view. 31. Carapace, dorsal view. 32. Eyes, dorsal view. 33. Labium, ventral view. 34. Leg IV, prolateral view. Scale bar = 10 mm for 34; 5 mm for 31; 2 mm for 29, 30, 32, 33. Photos: S. C. Nunn.

FIGURES 35 – 40. Lyrognathus achilles sp. nov., paratype male: 35. Sternum, labium, maxillae and coxa, ventral view. 36. Right maxillae, retrotrolateral view showing strikers. 37. Right chelicerae, intercheliceral pegs, prolateral view. 38. Right distal palp showing bulb, prolateral view. 39. Right distal palp showing bulb, retrolateral view. 40. Right bulb and embolus, ventro-anterior view showing keeled embolus. Scale bar = 10 mm for 35; 2 mm for 38, 39; 1 mm for 36, 37, 40. Photos: S. C. Nunn.

FIGURES 41 – 44. 41. Lyrognathus achilles sp. nov. Upper slopes of Gunung Nibung, Borneo, Indonesia. 42. Biotope, Gunung Nibung. 43. Biotope with arrow pointing to burrow entrance. 44. Detail of burrow entrance among foliage. Photos: 41 – 44: H. Yanto.