A New Species of Tarantula Spider in the Genus Lyrognathus Pocock 1895 ( Araneae , Theraphosidae ) from Sumatra

Lyrognathus Pocock 1895 belongs to the tarantula subfamily Selenocosmiinae Simon 1889 and was first described in northeastern India (L. crotalus Pocock [1], L. saltator Pocock [2]), then a century later in West Malaysia (L. robustus Smith [3], West [4]), and more recently on Borneo (L. achillesWest and Nunn [5], L. fuscus West and Nunn [5]) and Lombok islands (L. lessunda West and Nunn [5]). West and Nunn revised the genus [5] and in 2012 subjected Lyrognathus to cladistic analyses and also discussed biogeographical history of the group [6]. All previously described species have been recorded at higher elevations in montane habitat [1, 2, 4, 5, 7] and are a relatively medium to small-sized group [5]. Lyrognathus giannisposatoi sp. nov. is the most robust member of the genus and is the first to be recorded from Sumatra. L. giannisposatoi sp. nov. is unique among Lyrognathus in its preference for lowland elevations (F. Schneider, pers. comm.). A new key to species and map of Lyrognathus are also included.


Introduction
Lyrognathus Pocock 1895 belongs to the tarantula subfamily Selenocosmiinae Simon 1889 and was first described in northeastern India (L.crotalus Pocock [1], L. saltator Pocock [2]), then a century later in West Malaysia (L.robustus Smith [3], West [4]), and more recently on Borneo (L.achilles West and Nunn [5], L. fuscus West and Nunn [5]) and Lombok islands (L.lessunda West and Nunn [5]).West and Nunn revised the genus [5] and in 2012 subjected Lyrognathus to cladistic analyses and also discussed biogeographical history of the group [6].All previously described species have been recorded at higher elevations in montane habitat [1,2,4,5,7] and are a relatively medium to small-sized group [5].Lyrognathus giannisposatoi sp.nov. is the most robust member of the genus and is the first to be recorded from Sumatra.L. giannisposatoi sp.nov. is unique among Lyrognathus in its preference for lowland elevations (F.Schneider, pers.comm.).A new key to species and map of Lyrognathus are also included.

Material and Methods
Taxonomic description style follows Raven [8] and West and Nunn [5].All measurements are given in millimeters (mm) and were made to the nearest 0.01 mm with the aid of a squared eyepiece and digital dial callipers.Life images were taken with a Nikon CP8800 digital camera.Taxonomic images were taken by mounting a Nikon CP8800 digital camera to the phototube of a WILD Heerbrugg M8 stereozoom microscope (plus 1.6X objective lens) via the Scopetronix Maxview TM system, with external cold light illumination.Additional images of paratypes in the SMF were taken by Wirth with a Novex RZ Range trinocular microscope and a Nikon CP4500 digital camera, with external cold light illumination.The species diagnosis defines L. giannisposatoi sp.nov.from all others within the genus, not just its closest relatives.Leg and pedipalp measurements were taken from their dorsal aspect on the left side (unless appendages were lost or obviously regenerated) of all specimens, and coxae and trochantera were measured from their ventral aspect, on the same side.Eyes in sizes of largest to smallest (including distances taken at widest points in length/width, resp.).Claws are not included in the measurements of tarsi.Total body length measurements include chelicerae.Sternal sigilla measurements include labiosternal sigilla.Hair types are described (following [5]).Spermathecae were dissected from females and cleaned in concentrated lactic acid for 48 hours.Spermathecae of SMF type specimens were heated with concentrated lactic acid for about two to five minutes, until cleaned.The Leg formula is given in order of size from largest to smallest in both length and width.Leg relation factor [RF∼] (following [9]) is calculated by multiplying the length of leg I by 100, then dividing by the length of leg IV. 100 = equal sized leg I-IV, above 100 on a sliding scale representing a longer leg I, below 100 on a sliding scale representing a longer leg IV.Trichobothrial terminology follows Raven [8].Scopula extents are given as distal extents; that is, 2/3 means for distal two-thirds and refers to the ventral extent.DIVA-GIS Version 5.4.0.1 was utilized for geographic plotting.New type material will be housed at the QM (holotype female, 1 paratype female, and 1 paratype male), the SMF (4 paratype females and 1 paratype male), and the NHM (2 paratype females).Because mature females display more informative characters in Lyrognathus than males do, a female was selected as the holotype.Most types from this genus are female and some males are not known; therefore, the dichotomous key applies only to females.

Diagnosis
Description.Female holotype QM S95160 with body length: 44.58.Color (in life, Figure 1): Carapace dark brown, abdomen black, anterior legs I & II dark brown, anterior legs III & IV with all femora black, and with indistinct (greatly obscured by setae) cream bands on all leg segments distally.Dorsal coxae, trochantera palest of all.Ventrally black on sternum, coxae, with legs and abdomen as same as seen dorsally.Carapace (Figure 2): length 19.98, width 14.48 (width across anterior edge 10.6).Fovea 3.39 wide, procurved, deep, smaller in width than OT.The Distance from anterior carapace to fovea is 14.38.Carapace with 4 discernible hair types (C1 to C4): type C1, long, needle-form pallids bordering carapace entirely (darker basally), setae very dense in number: type C2, long and curling blunt tipped, basally dark grading to distally pallid, and cover entire carapace evenly, these setae grade to become entirely black toward the anterior edge of the carapace: 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 (>2) along anterior edge of each radial groove, (>6) along anterior edge of each thoracic groove, (>7) along anterior edge of each sulcal groove, (>12) 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.
Posterior end of patch truncate but rounded, anterior end rounded.Immediately above maxillary suture >23 elongated spines on anterior margin, rows disordered.
Claws: unarmed paired claws on all legs.Reduced third claw absent on leg IV.
Male paratype QMS95161 (SMF male type where mentioned, as in female except) with body length: 35.75.
Color (in life, Figure 5): Carapace and legs dark grey (except femora).Coxae and trochantera palest dorsally with a subtle pinkish color.Tarsi I & II with rufus longitudinal band dorsally.Abdomen and all femora black.All leg segments display strong distal white lateral banding.