A taxonomic revision of the tarantula spider genus Lyrognathus Pocock 1895 (Araneae, Theraphosidae), with notes on the Selenocosmiinae
Author
West, Rick C.
Author
Nunn, Steven C.
text
Zootaxa
2010
2362
1
43
journal article
10.5281/zenodo.275727
1e79f840-6ced-48b5-ab20-94992c6f0a88
1175-5326
275727
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
).
FIGURE 91.
Lyrognathus robustus
, adult female habitus, dorsolateral view. Photo: R. C. West.
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.
FIGURES 92–101.
Lyrognathus liewi
(jun. syn.
L. robustus
), paratype female QM S19651.15461. 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 = 10mm for 92, 98, 99; 5mm for 100; 2mm for 93–97; 1mm for 101. Illustrations: S. C. Nunn.
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
).
FIGURES 102–112.
Lyrognathus robustus
male QM S74340. 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 = 20mm for 102; 10mm for 108; 5mm for 109; 2mm for 104, 107, 110, 111; 1mm for 103, 105, 106; 0.5mm for 112. Photo & illustrations: S. C. Nunn.
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.