Lyrognathus fuscus, 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 : 19-25

Lyrognathus fuscus sp.nov.

( Figs 45–62 , 114 )

Types: female holotype, 3 female paratypes S88054 , S88051 , S88052 and S88053 , respectively, Simpang Kubur (2°29' S, 111°25' E), Katawaringin, Kotawaringin Barat, Borneo, Indonesia, col. H. Yanto, 2 Apr. 2009, QM.—examined.

Etymology: From Latin meaning dark brown/grey. The genus name is masculine, thus fuscus is the masculine form of the adjective.

Common name: Hariyanto’s tarantula, after the collector of this species.

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 having undivided scopula for full length of metatarsi IV, swollen distal lateral lobes of spermathecae but no third claw on tarsi IV. Differs from L. lessunda sp. nov. in the absence of “mushroom cap” medial lobes of the spermathecae. Differs from L. achilles sp. nov. in less pronounced maxillary lobe, lack of distal cream/white leg segment bands, smaller size, color and proximal-distal gradation of retrolateral tibiae IV penicillate brush (uniform for length in L. achilles sp. nov.).

Description: Female holotype ( Fig. 45 ) with body length: 45.87.

Color (in life, Fig. 45 ): Entirely dark brown/grey, no distal leg segment bands.

Carapace ( Fig. 47 ): length 16.96, width 12.77 (width across anterior edge 8.85). Fovea 2.20 wide, procurved, deep, smaller in width than OT. Distance from anterior carapace to fovea, 12.51; with 4 discernible hair types (C1 to C4): type C1, long needle-form pallids border carapace entirely; type C2, short black, blunt tipped, entirely over carapace; type C3, short thin, wavy pallids, form basis of mat; type C4, emerge from bothrial-like collars, long, distally spiniform, pallid, in uniform arrangement: (>5) along anterior edge of each radial groove, (>4) along anterior edge of each thoracic groove, (>5) along anterior edge of sulcal groove, (>6) along anterior edge of each caput groove, (>4) along medial caput ridge (between OT/fovea), (>3) located behind each side of OT, nearest median caput row.

Eyes ( Fig. 48 ): ocular tubercle; length 1.95, width 2.91. OT highest posteriorly behind AME, sloping gradually anteriorly. Anterior row slightly procurved. Posterior row recurved. Eyes in lengths/widths: AME: 0.67/0.51, ALE: 0.71/0.27, PLE: 0.41/0.25, PME: 0.40/0.28. Inter-ocular distances: AME–AME: 0.28, AME– ALE: 0.24, AME–PME: 0.15, ALE–ALE: 1.79, ALE–PME: 0.41, PME–PME: 1.43, PME–PLE: 0.19, PLE– PLE: 2.0, ALE–PLE: 0.38. OT hairs:>15 (C2) directly posterior to AME’s, two between PME and center of OT (behind AME). 16 (C2) along median anterior OT surface. OT entirely covered in small, weak, pallid setae (C3), directionally point to center of OT, posteriorly–anteriorly. Lateral small pallids very sparse with no uniform direction/random arrangement.

Chelicerae (right, Figs 58–62 ): length 8.90, width at base of lobe 4.15 (bases widest point, dorsally). Ectal lyrate region a series of strikers (>75), 8 horizontal rows ( Fig. 59 ). Strongest and longest strikers on lowest rows. Each striker very stout, blade or scimitar-shaped with long filiform ends. Teeth, 13,>40 basomesal teeth. Intercheliceral pegs (>11 larger,>18 smaller) in tight cluster on basodorsal surface, extremely stout, 1/2 as wide as long ( Fig. 62 ). Retrolaterally and basomedially, small cluster of short strong spiniform setae (>7) point distad ( Fig. 60 ). Surrounding spines a patch of fine setae, dark, of medium length, blends into typical thicker pallid cheliceral setae. Setae filiform and seem to emerge from hemispherical bases.

Maxillae ( Figs 49 , 56 ): prolaterally plano-convex, anterior lobe well pronounced, many cuspules (> 105) on inner basoventral surface. Lyra ( Figs 56, 57 ): large number of bacilliform rods (>180) form dense, ovoid patch on prolateral maxillary surface (3.23 long, 1.72 high), lowest row with up to>18 bacillae, longest rods in center of lowest rows. Rods distally paddle-shaped (paddles up to 0.19 long) with short to medium length shafts (total length 0.69), largest rods with no distal blades. At widest point, lyrate patch 10 rows deep, smallest rods dorsally. Posterior end of patch truncate, anterior end not pointed distad/widely rounded. Immediately above maxillary suture>45 elongated spines on anterior margin in disordered rows. Labium ( Fig. 50 ): length 2.35, width 3.0. Many small cuspules (>540) along anterior 1/4 surface. Labium with 2 discernible hair types (L1, L2); type L1: long, reasonably dark spiniform, curve distally toward anterior, most concentrated along lateral borders. Setae longest along anterior edge (>35); type L2: 1/2 length of L1, interspersed with L1 but darker, more needle-form.

Sternum ( Fig. 49 ): length 7.65, width 6.68, saddle-form; with 5 discernible hair types (S1 to S5): type S1, longest, thick blunt tipped, darker basally, become pallid distally, entire but sparse; type S2, elongate spiniforms, entirely dark, on borders, most concentrated posteriorly; type S3, similar morphology to S1, although only 1/4–1/2 length in comparison, over entire surface, sparse; type S4, short, thin pallids, form basis of mat; type S5, short, black blunt tipped, entirely cover sternum in sparse disordered arrangement. Posteriorly between left and right coxa IV, border highly acuminate, lateral points slightly acuminate. Sigilla: 3 pairs, posterior, large; right with length 1.31, width 0.65, left length 1.0, width 0.6. Ovular, 1.65 apart, 1.35– 1.38 from margin. Median pair, 1/2 size of posterior, similar shape, 1.0–0.6 of their length from margin.

Anterior pair 1/3 size of posterior, somewhat obscured, border sternal margin. Labio-sternal sigilla large, only slightly smaller than PSS.

Legs: formula (length); IV, I, II, III: (width); IV, III, I, II. Leg RF ~86.72. Leg lengths (fem., pat., tib., met., tar., total): palp: 9.32, 5.73, 6.13, 0.00, 5.10, 26.28. I: 12.48, 7.92, 9.26, 7.68, 4.99, 42.33. II: 10.78, 6.93, 7.21, 7.31, 4.71, 36.94. III: 9.32, 5.93, 5.5, 7.22, 4.23, 32.2. IV: 13.73, 7.39, 10.43, 11.85, 5.41, 48.81. Leg widths (fem., pat., tib., met., tar., total.): palp: 2.36, 2.61, 2.17, 0.00, 2.26, 9.4. I: 3.08, 3.11, 2.99, 2.13, 2.05, 13.36. II: 3.06, 3.12, 2.57, 1.95, 1.89, 12.59. III: 3.8, 3.32, 2.91, 2.10, 1.96, 14.09. IV: 3.41, 3.26, 3.44, 2.35, 2.01, 14.47. Tib. IV with strong retrolateral penicillate setal fringe, proximally weak, gradually increases distally ( Fig. 53 ).

Scopula: Met., tar. I–III undivided, met. IV undivided, tar. IV partially divided proximally (by one row of sparse setae, 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, about 1.3 times longer than 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 6.75, width 4.12; I–7.23, 3.3; II–5.68, 2.83; III–4.44, 3.43; IV–6.3, 3.95. Trochantera: palp–length 2.65, width 1.85; I–3.05, 3.41; II–2.65, 2.78; III–2.45, 2.8; IV–3.1, 3.8.

Trichobothria: All tarsi with 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 II–IV cf. I, in distal 1/2. Shorter filiforms for length. Short epitrichobothrial field on I shorter than clavates, increase in length proximally. Tarsal organ evident on legs I–III under stereo microscope (up to x64), organ on tar. I 1 /2 size cf. II and III, low, wide, domed without noticeable ridges. On tar. I, entire field 3.3 long, 0.98 wide distally, to 1.3 wide proximally. On tar. IV, field 3.89 long, 0.85 wide distally, increase to 1.35 proximally. Metatarsi: trichobothrial field not evident laterally or proximally. Tibia: on I prolaterally and proximally, short, possibly clavate trichobothria noted (>8 per 0.25mm squared) in Lshaped patch 0.25 long, 1.25 wide, clearly pallid:>6 filiforms in semicircular pattern proximally to rest of patch; on 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, met. III with 2 DV, 1DPV, 1 DRV, 1 DD, met. IV with 2 DV, 1DPV, 1 DRV, 1 DD.

Claws: unarmed claws on all legs and palps. Third claw absent on leg IV.

Abdomen ( Fig. 52 ): 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 in color; type A2, mid-length, dark, but distally spiniform, unlike type 1; type A3, form dense mat of abdomen, mid-length, uniformly dark colored, needle-form (some stand erect, some run posteriorly along abdomen, both share similar morphology). Longest hairs (type A1) more concentrated posteriorly toward spinnerets, pointing distad, but proximally, hairs stand erect and medially curved (toward posterior). Ventral hair types almost same as dorsal, with type A2 and A3 denser entirely. Type 4 hair (A4) in very dense patch, trapezoid in shape, just posterior to pedicel, between median regions of cox. IV. Hairs of medium length, but wavy, pallid. Between anterior pair of booklungs, setal mat jet black, much darker than rest with more concentrated setal counts ( Fig. 52 ).

Genitalia ( Fig. 51 ): epigastric fold 6.2 wide. Spermathecae paired, not fused, separated by 0.8 (width including spermathecae 4.1), bilobular apically, each lobe with strong apical rounded appendages, lateral/ outer lobes more defined distally–ovular; lateral lobe distal, widths 0.62 (left)–0.51 (right): medial lobe distal widths 0.32 (left)–0.31 (right), heavily sclerotized gradual transition to weakly sclerotized shafts proximally. Lobes apically swollen, lateral lobes (including shaft length) 4/5 length to medials (1.12 to 1.2, respectively). Epigastric fold extends to about 2/3 length of spermathecal lobes.

Spinnerets: PMS: length 0.71, width (medially) 0.56. PLS: section lengths; basal 2.75, medial 1.46, apical 2.21. PLS section widths (medially); basal 1.35, medial 1.18, apical 0.75. 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 unknown.

Distribution and natural history ( Fig. 114 ): Known only from the type locality, Simpang Kubur, Katawaringin, Kotawaringin Barat, Borneo, Indonesia. Little is known; however, L. fuscus is a fossorial spider that lives in higher shaded tropical forests away from the riparian flood plains. Burrows were only found on sloped embankments amongst leaf litter and low vegetation and were formed in clay-like soil (H. Yanto, pers. comm.).

Figures

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

FIGURES 45 – 46. Lyrognathus fuscus sp. nov. 45. Holotype female in life. 46. Male in life. Photos: 45, R. C. West; 46, H. Yanto.

FIGURES 47 – 52. Lyrognathus fuscus sp. nov. holotype female: 47. Carapace, dorsal view. 48. Eyes, dorsal view. 49. Sternum, labium, maxillae and coxa, ventral view. 50. Labium, ventral view. 51. Spermathecae, dorsal view. 52. Abdomen, ventral view. Scale bar = 10 mm for 47, 49, 52; 2 mm for 48, 50; 1 mm for 51. Photos: S. C. Nunn.

FIGURES 53 – 57. Lyrognathus fuscus sp. nov. holotype female (except paratype QM S 88051; 56 – 57): 53. Left leg IV, dorsal view. 54. Left leg IV, retrolateral view. 55. Left met, tar. IV, prolateral view. 56. Left maxillae, prolateral view. 57. Maxillary lyra, prolateral view. Scale bar = 10 mm for 53 – 55; 2 mm for 56; 1 mm for 57. Photos: S. C. Nunn.

FIGURES 58 – 62. Lyrognathus fuscus sp. nov. paratype female QM S 88051: 58. Left chelicerae, retrolateral view. 59. Left cheliceral strikers, ectal view. 60. Basomedial cheliceral spines, retrolateral view. 61. Left chelicerae, prolateral view. 62. Left intercheliceral pegs, prolateral view. Scale bar = 5 mm for 58, 61; 2 mm for 59; 1 mm for 60, 62. Photos: S. C. Nunn.