Lyrognathus robustus Smith 1988

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 : 31-36

Lyrognathus robustus Smith 1988

( Figs 91–112 , 114 )

Lyrognathus robustus Smith 1988: 15 –19, figs1–9; Platnick, 2009.

Lyrognathus liewi West 1991: 615 –619, figs 1–11. Schmidt & von Wirth 1992: 10.

Types: Lyrognathus robustus Smith 1988 , female holotype, 1988.2.6, Cameron Highlands, Malaysia, (unknown collector and date), NHM.–images (R. Raven, pers. comm.)–examined; Lyrognathus liewi West 1991 , female holotype, 2 female paratypes, S15460 , S15461 and S15462 , respectively, 24 mile road marker, Cameron Highlands (4°41' N, 101°52' E), Pahang, West Malaysia, col. K. C. Liew, Oct.–Nov. 1986, QM.–images (R. Raven, pers. comm.)–examined.

Other material: 3 females, 1 male, S74339, S74341, S74342 and S74340, respectively, Cameron Highlands, Pahang, West Malaysia, QM–examined; 1 male, S88073 , Maxwell Hill (= Bukit Larut, 4°52΄ N, 100°48΄ E), Perak, West Malaysia, QM–examined; 2 females, ZRC ARA.747, Taiping (4°51' N, 100°48' E), Perak, West Malaysia, col. H. C. Abraham, 1 Nov. 1925, RMBR.–images (D. Court, pers. comm.)–examined.

Diagnosis: Differs from other Lyrognathus species in the basally incrassate metatarsi IV that tapers distally ( Fig. 99 ). Also differs from all other species in having uniquely divided scopula on metatarsi IV, a third claw on tarsi IV ( Fig. 98 and see: Character discussion) and bilobular spermathecae without apical swelling ( Fig. 101 ).

Description: female QM S15641 (unless otherwise stated) with body length: 38.14.

Color (in alcohol): reddish brown with darker femora on all legs.

Carapace: length 16.7, width 12.8 (width across anterior edge 9.6). Fovea 2.3, procurved, deep, very wide.

Eyes ( Fig. 93 ): ocular tubercle; length 1.85, width 2.65. Anterior row transverse. Posterior row slightly recurved. Sizes: AME, ALE, PLE, PME.

Chelicerae ( Figs 95, 96 ): length 6.05, width at base of each lobe 4.25. Ectal lyrate region a series of strikers (>80), up to 7 disordered horizontal rows ( Fig. 96 ). Strongest and longest strikers on lowest rows. Each striker needle-form with some filiform ends. Teeth: 14 (with>2 small teeth proximally) and>60 basomesal teeth. Intercheliceral pegs (>7 larger,> 20 smaller) in tight cluster on basodorsal surface ( Fig. 95 ). On retrolateral surface basomedially, with small cluster of short strong spines (>3) point distad ( Fig. 96 ).

Maxillae ( Figs 94, 97 ): prolaterally plano-convex. Anterior lobe well pronounced. Many cuspules (>320) on inner basoventral surface. Diagonally of anterior lobe, a basal projection with long stout setae. Lyra ( Fig. 97 ): many bacilliform rods (>280) form dense, ovoid patch on medial prolateral surface, lowest row with up to>40 bacillae, longest rods finish center of lowest row. Rods distally paddle-shaped with long shafts, some with distal blades. Truncate posteriorly. At widest point, lyrate patch up to 10 rows deep with smallest rods dorsally. Immediately above suture, 30 small spines on anterior margin. Labium: length 2.55, width 3.67. Many small cuspules (>600) along anterior 1/3 surface.

Sternum: length 7.65, width 6.9. Slightly wider posteriorly than anteriorly, with even cover of short setae, interspersed with longer darker setae. Lateral and posterior points acuminate with series of short stout setae cover posterior points. Sigilla: 3 pairs; posterior pair, large, 3.2 lengths apart, 1.85 of their length from margin. Median pair 1/2 size of posterior, similar shape, border margin. Anterior pair smallest, somewhat obscured, border margin. Labio-sternal sigilla largest, separated by their own diameter. Some strong spiniform setae around posterior edges, border cox. III/IV.

Leg setation: retrolateral surfaces of pat., tib. and met. IV with distinct thick short brushes of penicillate setae. Legs: formula; (length only) IV, I, II, III. Leg RF ~82.67. Leg lengths (fem., pat., tib., met., tar., total): paratype S15460 : palp: 9.08, 5.76, 6.49, 0.00, 5.94, 27.18. I: 14.02, 9.02, 9.9, 8.42, 4.95, 46.31. II: 11.72, 7.87, 7.98, 7.7, 4.57, 39.84. III: 10.78, 6.99, 6.77, 8.91, 4.4, 37.85. IV: 14.69, 8.8, 12.21, 15.4, 5.5, 56.6. S15460 : palp: 9.15, 5.65, 5.85, 0.00, 5.9, 26.55. I: 11.95, 7.8, 9.3, 7.35, 5.35, 41.75. II: 10.2, 6.85, 6.45, 6.7, 5.0, 35.2.

III: 8.95, 5.85, 5.6, 7.65, 5.2, 33.25. IV: 13.25, 7.1, 11.25, 12.9, 6.0, 50.5. Tib. IV incrassate. Met. IV basally incrassate, tapers distally. Tar. IV with transverse suture at distal 1/3 of tarsus, most obvious ventrally and laterally ( Fig. 100 ).

Scopula: on met./tar. I–IV. Undivided on met./tar. I–III. Met. and tar. IV divided by band of extremely strong spiniform setae with scopula only on apical 1/3 of met. IV ( Fig. 98 ).

Coxae: many short black thorns prolatero-dorsally, no thorns retrolaterally I–IV; easily seen dorsally. I longest, ca. 1.8 times length of II. IV widest, 1.3 times longer than III, basally rectangular with rounded corners; with ventral thorns prolaterally on I–IV. I–III ventrally with many long thick blunt setae, pallid, some short black setae intermixed. IV with mixture of long thick blunt setae, pallid intermixed with shorter thin pallid setae. Ventral surface of I–IV gently sloping anteriorly. Retrolateral setation: I–III with median narrow light brush, IV completely covered in light setae. I–IV retrolaterally lack ventral ledge, ventrally with uniform setation. Ventral measurements: I length 7.2, width 3.1; II 6.1, 3.1; III 5.8, 2.9; IV 6.7, 4.4. Trochantera (ventral): I length 4.0, width 3.8; II 3.4, 3.1; III 2.8, 2.7; IV 4.0, 3.9.

Trichobothria: tarsi: on all, basal filiform field slightly wider than clavate field, merges evenly. Clavates on tar. I only in distal 1/2, long filiforms only in basal 1/2, shorter filiforms intermixed with clavates distally. Clavate extent on II–IV cf. I, only in distal 1/2. Shorter filiforms for length. Short epitrichobothrial field on I shorter than clavates, increasing in height proximally. Tarsal organ visible (coniform, high domed), positioned immediately behind prolateral paired tarsal claw, but obscured by border setae, on legs I–IV.

Spines: met. I with 1 DV, met. II with 1 DV, 1 DPV, 1 DRV, met. III with 2 DV, 1 DPV, 1 DRV, 1 DD and met. IV with 2 DV, 1 DPV, 1 DRV, 1 DD, 1 DL. Disordered cluster of small, short spines cover entire ventral region of met. IV outside scopulate area ( Fig. 98 ).

Claws: unarmed paired claws on all legs. Reduced third claw on leg IV ( Fig. 100 ).

Genitalia ( Fig. 101 ): spermathecae typically bilobular, dividing basally. Lobes not apically swollen, with lateral lobes 2/3 length of medials. Medials very long. Heavily sclerotized distally, proximally reduces to weak sclerotization at bases of all lobes. N.B.: West (1991) noted extreme variation in types held at the QM. In one example (type: S15641 ), the spermathecae were trilobular, in another (type: S15460 ), a bud was present on one of the medial lobes.

Male QM S74340 ( Fig. 102 , as in female except) with body length: 28.54.

Color (in alcohol): dark brown in natural lighting.

Carapace ( Fig. 102 ): length 11.2, width 10.1 (width across anterior edge 6.3). Fovea 1.8, distinctly procurved, deep.

Eyes ( Fig. 103 ): ocular tubercle; length 1.2, width 2.1. Anterior row transverse. Posterior row slightly recurved. Sizes: AME, ALE, PLE, PME.

Chelicerae: length 6.7, width at base of each lobe 4.8. Teeth: 12 with>40 small basomesal teeth. Intercheliceral pegs (>2 larger,>13 smaller) in tight cluster on basodorsal surface ( Fig. 105 ).

Maxillae ( Figs 104, 107 ): anterior lobe well pronounced, many cuspules (>280) on inner basoventral surface. Lyra ( Fig. 107 ): immediately above suture no elongated spines (only typical hair-like setae) medially to anterior margin. Labium ( Fig. 104 ): length 1.4, width 2.3. Many small cuspules (>500) along anterior 1/4 surface.

Sternum ( Fig. 104 ): length 5.4, width 4.2. Clearly wider posteriorly than anteriorly, with even cover of short setae, interspersed with many longer darker setae. Differs from females in that no spiniform setae around edges.

Legs: formula; (length) IV, I, II, III; (width) III, IV, I, II. Leg RF ~93.45. Leg lengths (fem., pat., tib., met., tar., total): palp: 10.1, 5.15, 9.05, 0.00, 2.9, 27.2. I: 12.5, 6.75, 10.6, 9.55, 6.43, 45.83. II: 11.2, 5.9, 8.94, 8.95, 5.6, 40.59. III: 9.05, 4.65, 6.7, 8.85, 5.53, 34.78. IV: 12.6, 6.15, 10.4, 14.55, 5.34, 49.09. Leg mid-widths (fem., pat., tib., met., tar., total.): palp: 2.15, 2.03, 2.02, 0.00, 2.4, 8.6. I: 2.45, 2.35, 2.2, 1.95, 1.63, 10.58. II: 2.44, 2.35, 2.15, 1.87, 1.5, 10.31. III: 3.9, 2.9, 2.05, 1.83, 1.75, 12.43. IV: 2.43, 2.85, 2.3, 1.82, 1.72, 11.12. Coxae ventral measurements: palp–length 4.99, width 2.16; I–5.21, 2.66; II–4.94, 2.66; III–4.04, 2.67; IV– 4.52, 2.70. Trochantera ventral: palp–length 1.79, width 1.97; I–2.16, 2.29; II–2.05, 2.17; III–2.13, 2.41; IV– 2.16, 2.45.

Genitalia. Palp ( Figs 109–112 ): tib. with dorsal arrangement of distinct long pallid sensory setae 2–1–2 (proximally, medially and distally), distal pair with medial bend dorsally, as in typical metatarsal distal paired sensory setae ( Fig. 109 ); embolus tip tapers distally with no flaring ( Fig. 110 ). Twisted through 90° at tip. Relative length of tib. about twice length of embolus. No longitudinal keel ( Fig. 112 ).

Distribution and natural history ( Fig. 114 ): L. robustus is found among the wet montane forested regions of Cameron Highlands, Pahang State, in the main Central range and from Baling, Kedah State and Bukit Larut and Gerik, Perak State in the Eastern range of West Malaysia. L. robustus construct simple tubular burrows in clay-like soil with either a plain opening or a slight flare-mouth that utilizes surrounding organic debris or vegetation around the mouth on sloped or nearly vertical embankments. Adult female burrows were J-shaped and terminatined in an enlarged chamber about 18–30 cm deep. An ultimate male was found in a burrow in January (S. Hogg, pers. comm.). A “nervous” spider, L. robustus will readily bite if provoked (West, pers. obs.). The local native Orang Asli people know these tarantulas as “Tei Foo” (translates as “Earth Tiger”) and still believe the bite to be fatal ( West 1991, p. 616).

Remarks: Von Wirth (2000, p.17) discussed some issues between L. robustus and Coremiocnemis species within Malaysia, compared to Lyrognathus of India. He assumed it might be best to transfer L. robustus into Coremiocnemis based on plesiomorphic metatarsal scopula division on leg IV that L. robustus shares with Coremiocnemis , as well as presence of intercheliceral pegs and bilobular spermathceae, not known in Lyrognathus prior to Smith’s L. robustus description. He also considered zoogeographic ranges for both groups. However, with the inclusion of three new Lyrognathus species that display traits diagnostic of Lyrognathus (undivided scopula on metatarsi IV), but share with L. robustus the presence of intercheliceral pegs and bilobular spermathecae and further, are found within Indonesia, the previously considered dubious placement of this species into Lyrognathus is no longer questionable. Further, clavate trichobothria on tarsi of L. robustus are like that in all other Lyrognathus and not those of any Malaysian Coremiocnemis species. Male embolus morphology does not conform to Coremiocnemis either, lacking a distal “kiss curl” (West & Nunn, in press). There is at most likely a close relationship shared between Lyrognathus and Coremiocnemis by way of several shared derived characters (see: retrolateral cheliceral spines and spermathecae in Character discussion), however, the presence of penicillate retrolateral setal brushes on tibiae IV in combination with incrassate tibiae IV in females and ventral projection of the male embolus is seen only in Lyrognathus . L. robustus shows some traits that differ from other members of the genus and, in that regard, might be considered the most extreme representative of Lyrognathus , but cannot be considered separate to the group as it clearly does not fit Coremiocnemis or any other selenocosmiine genus as suggested by von Wirth (2000). The inclusion of L. achilles sp. nov., L. fuscus sp. nov. and L. lessunda sp. nov., herein, shows that traits such as intercheliceral pegs, bilobular spermathecae, retrolateral basomedial cheliceral spines and zoogeographic ranges outside of India clearly fit parsimoniously within Lyrognathus .

Even though L. liewi was placed as a junior synonym of L. robustus , a subsequent search through the senior author’s collection yielded a male, now deposited in the QM. A second L. robustus male was located near the summit of Bukit Larut, Perak, West Malaysia by Mr Stephen Hogg, and then donated to the QM. So far no other males from L. robustus have ever been located, in these specimens, informative characters exist that are not present in females, hence the need to define the male here.

Figures

FIGURE 91. Lyrognathus robustus, adult female habitus, dorsolateral view. Photo: R. C. West.

FIGURES 92 – 101. Lyrognathus liewi (jun. syn. L. robustus), paratype female QM S 19651.15461. 92. Habitus, dorsal view. 93. Eyes, dorsal view. 94. Sternum, labium and right maxillae, ventral view. 95. Intercheliceral pegs, prolateral view. 96. Right chelicerae, lower retrolateral view showing strikers and arrow pointing to retrolateral basomedial cheliceral spines. 97. Right maxillae showing lyra, prolateral view. 98. Right leg IV, ventral view. 99. Right leg IV, retrolateral view. 100. Right tar. IV, prolateral view showing transverse suture and reduced third claw. 101. Spermathecae, dorsal view. Scale bar = 10 mm for 92, 98, 99; 5 mm for 100; 2 mm for 93 – 97; 1 mm for 101. Illustrations: S. C. Nunn.

FIGURES 102 – 112. Lyrognathus robustus male QM S 74340. 102, Habitus, dorsal view. 103. Eyes, dorsal view. 104. Sternum, labium and right maxillae, ventral view. 105. Right intercheliceral pegs, prolateral view. 106. Right lower retrolateral cheliceral surface showing strikers and retrolaeral basomedial spines. 107. Right maxillae showing lyra, prolateral view. 108. Right leg IV, ventral view. 109. Right palpal tibia, prolateral view. 110. Right bulb, retrolateral view. 111. Right bulb, prolateral view. 112. Left embolus, transverse cross section. Scale bar = 20 mm for 102; 10 mm for 108; 5 mm for 109; 2 mm for 104, 107, 110, 111; 1 mm for 103, 105, 106; 0.5 mm for 112. Photo & illustrations: S. C. Nunn.

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