Preliminary Review of Indian Eumenophorinae (Araneae: Theraphosidae) with Description of a New Genus and Five New Species from the Western Ghats

The theraphosid spider genera Heterophrictus Pocock, 1900 and Neoheterophrictus Siliwal & Raven, 2012 are rediagnosed in this paper and a new genus, Sahydroaraneus gen. nov. is described from Southern Western Ghats. Four new species (two each of Heterophrictus and Neoheterophrictus) and one of Sahydroaraneus gen. nov. are described from the Western Ghats. Plesiophrictus mahabaleshwari Tikader, 1977 is removed from the synonymy of Heterophrictus milleti Pocock, 1900 and is treated as a junior synonym of Heterophrictus blatteri (Gravely, 1935). Plesiophrictus bhori Gravely, 1915 is transferred to the genus Neoheterophrictus, Neoheterophrictus bhori (Gravely, 1915) new combination. The genus, Sahydroaraneus gen. nov., resembles tarantula belonging to the genus, Neoheterophrictus but differs with respect to structure of tibial apophysis and spermathecae. Detailed ultra-structure of setae type of the Indian Eumenophorinae is presented for the first time along with notes on their biogeography. Common elements among Africa, Madagascar and India like the Eumenophorinae and several other mygalomorph spiders advocate mygalomorphae as an important group for evolutionary investigation due to their inability for long distance dispersal rendering the members restrictive in distribution.


Introduction
Theraphosidae Thorell, 1870 is the most speciose of all mygalomorph spider families with 946 species and 124 genera [1,2]. In India, it is represented by eleven genera and fifty five species [3][4][5]. Major taxonomic work concerning the family was carried out about 100 years ago [see [6][7][8] with the exception of the generic revision by Raven [9]. Theraphosidae in India is represented by the following subfamilies: Eumenophorinae, Ischnocolinae, Poecilotheriinae, Selenocosmiinae, Selenogyrinae and Thrigmopoeinae. There have been some notable additions to the list of Indian theraphosid spider by Tikader [10]. However, there are erroneous implications which have recently been rectified [3,[11][12][13]. A new species of Plesiophrictus Pocock, 1899 was described from the Western Ghats [14] and two new species of Poecilotheria Simon, 1885 were also described [15,16]. Recently, a new genus and three new species from the Western Ghats were also discovered [17] further highlighting the taxonomic richness and the lack of our knowledge of this family in India as a whole. Most species in India were described almost a century ago and lack valuable morphological details warranting redescription of most species [11][12][13][14].
The monotypic genus Heterophrictus Pocock, 1900 was described with H. milleti as its type species. The new genus was distinguished from Plesiophrictus by possessing procurved fovea in the former and straight in the later Pocock [6]. Heterophrictus was diagnosed by the presence of long setae above the suture of the prolateral face of the first coxae, the shape of thoracic fovea and the posterior sternal sigilla remote from sternal margin [18]. Doubts were raised on Pocock's [6] and Simon's [18] distinction, based on slight differences in shape of the fovea and setae in Heterophrictus/ Plesiophrictus to be related to size and to be variable even among adults by Gravely [7]. Heterophrictus and Ischnocollela Strand, 1907 were synonymized with Plesiophrictus [9] since they share all characters of generic significance. Recently, Heterophrictus was resurrected from the synonymy of Plesiophrictus and placed in the subfamily Eumenophorinae, [19] adding a new subfamily to India. More details of the genus Plesiophrictus were added by Sanap & Mirza [12] which enables us to compare it with closely related genus Heterophrictus as well as Neoheterophrictus  in Siliwal et al. [5].
The Western Ghats is a biodiversity hotspot and is known for its rich and endemic fauna [20]. With a few exceptions, however, its invertebrate fauna remains poorly known [13,[21][22][23]. While documenting the mygalomorph spiders of the Western Ghats several theraphosid spiders were collected. Four of the collected species could not be attributed to any of the known sub-family or genera from India following Pocock [6], Gravely [7,8] and Smith & Kirk [24]. The collected material possessed type III stridulatory organ presented in Eumenophorinae [25] and Theraphosinae Thorell, 1869 as described by Vol [26]. The specimens differed from Theraphosinae because they lacked abdominal urticating setae and palp bulb keels [27] and were thus tentatively assigned to the sub-family Eumenophorinae. After comparison of the collected material with Raven [9], Guadanucci [5,19] it was confirmed that the material belongs to the subfamily Eumenophorinae.
The Eumenophorinae, characterized by presence of stridulatory spike setae between coxae of leg I-IV and stiffened brush of setae on palp femur in most genera, are presently known by eleven genera [28] distributed throughout Africa, southwestern countries in Saudi Arabia, Madagascar and associated islands [25,[29][30][31]. In the recent past, a new genus and a new species of the sub-family Eumenophorinae was described from Mauritius [29] was described which lacks stridulatory setae. Even though valuable contributions were made through publications of Smith [30,31] despite this, members of the sub-family remain poorly known.
After a detailed comparison of the specimens collected from the Western Ghats with Guadanucci [19], Raven [9] and Smith [30,31], it was found that the specimens belonged to two different genera and four new species. Based on Guadanucci [19] and  Siliwal et al. [5], two of the species were attributed to the genus Heterophrictus and the other two species were accommodated into the newly described genus Neoheterophrictus Siliwal & Raven, 2012.
Neoheterophrictus was described with description of three new species from the Western Ghats of Karnataka [17] and it was mentioned that the new genus resembles Plesiophrictus and Heterophrictus.
Neoheterophrictus differs from Plesiophrictus in many aspects, however its distinction from Heterophrictus has not been satisfactorily justified [12) and hence a rediagnosis of the genus is needed. Recent collection of specimens of Heterophrictus and Neoheterophrictus of both sexes shed light on taxonomy of these genera based on which we    rediagnose both the genera in this paper adding two new species to each from the Western Ghats. Around 158-160 million years ago, Gondwana split and the Indo-Madagascan plate started separating from Africa. The Indian plate then broke away from Madagascar ca. 84-96 million years ago [32], drifted northward and collided with Eurasia between 55.5 and 66 million years ago. Thus, initially the Indo-Madagascan plate was isolated from Africa, and then the Indian plate was isolated from both Madagascar and Africa for extended periods of time. When India broke off from Africa and later from Madagascar, it carried away Gondwanan forms with it ( Fig. 1a, b, c), most of which became extinct due to the late Cretaceous climatic conditions while others survived dispersing and colonizing suitable regions of India ( Figure 1) [33]. Interestingly, majority of these Gondwanan forms are presently distributed in the Western Ghats and Sri Lanka, however more detailed surveys are necessary to confirm this. One such Gondwanan form is the frog genus Nasikabatrachus, which is a relic from the ancient Indo-Madagascan plate [34,35]. Recently, the barychelid genus Tigidia Simon, 1892 was reported from the Western Ghats of India with description of three new species [36] which was until know known only from African region, further highlighting ancient biogeographic links.
As part of our study on Indian mygalomorphae, ZM & RS visited the Natural History Museum, London and examined types of material collected from India. Most material assigned to the genus Plesiophrictus was examined and were found to belong to the subfamily Eumenophorinae and have here been formally transferred to respective genera (Table 1). Hirst [37] described Annandaliella travancorica based on a female specimen and later Gravely [7] assigned a male collected from near Cochin to A. travancorica. We examined the male and female specimens in the collection of the Natural History Museum and based on characters like absence of inter-cheliceral peg setae in the male and presence of horizontally aligned modified setae on the coxa of legs (a character unique to the Eumenophorinae) clearly justifies its placement in the Eumenophorinae. After detailed comparison with Heterophrictus and Neoheterophrictus, we here describe the male attributed to A. travancorica by Gravely [7] as a new species and erect a new genus to embody it.

Methods
Specimens were collected during the surveys conducted in Aarey Milk Colony (Mumbai, Maharashtra) and on random visits to other collection areas. Specimens have been deposited at Zoological Survey of India/Western Regional Centre, Pune (ZSI/ WRC) and Bombay Natural History Society, Mumbai, Maharashtra (BNHS). Comparative material for the study was examined from the collection of the Natural History Museum, London and diagrams of type specimens from University of Copenhagen, Zoological Museum (ZMUC, Denmark). Measurements of body parts were taken with an Aerospace Dial Caliper. Measurements of the chelicerae have being taken of the lateral aspect after dissection. All measurements are in mm. and total length excludes chelicerae length. Spermathecae were dissected and cleaned in clove oil using needles. Specimens were examined using Labomed CSM2 stereo-binocular microscope. Photographs of the specimens in India were taken with a Nikon D50 mounted with a Nikon 105 mm macro and extension tubes and those at the Natural History Museum (NHM, London) with an imaging system on Leica MZ12S. Descriptive style follows standardized descriptive style provided by Raven [38]. Specimens were coated with 50 mA of platinum for 50 seconds and were scanned using Joel JSM-7600F Field Emission Scanning Electron Microscope for analyzing ultra structure of stridulatory and tarsal setae. Abbreviations: AMC -Aarey Milk Colony, ALE -Anterior lateral Eyes; AME -Anterior Median Eyes; BMNH -Natural History Museum, London; BNHS -Bombay Natural History Society, Mumbai; ddorsal; fe -femur; HB -Harshal Bhosale; mt -metatarsus; MOQ -Median ocular quadrate; p -Prolateral; pa -patella; PLE -Posterior lateral eyes; PLS -Posterior lateral spinnerets; PME -Posterior median eyes; PMS -Posterior median spinnerets; rretrolateral; RS -Rajesh Sanap; ta -tarsus; ti -tibia; v -ventral; ZM -Zeeshan Mirza and ZSI/WRC -Zoological Survey of India/Western Regional Centre.

Ethics Statement
All specimens were collected from areas outside Protected Areas and did not involve any endangered or protected species; hence collection and/or study permits were not required which complied with all relevant regulations. Permission to use data, diagrams and image of examined material was obtained from curators of museums for this study.

Nomenclature Acts
The electronic edition of this article conforms to the requirements of the amended International Code of Zoological Nomenclature, and hence the new names contained herein are available under that Code from the electronic edition of this article. This published work and the nomenclatural acts it contains have been registered in ZooBank, the online registration system for the ICZN. The ZooBank LSIDs (Life Science Identifiers) can be resolved and the associated information viewed through any standard web browser by appending the LSID to the prefix ''http://zoobank.org/''. The LSID for this publication is: urn:lsid:zoobank.org:pub: urn:lsid:zoobank.org:pub:856F44CD-CFA3-42CB-A728-5454157264B6. The electronic edition of this work was published in a journal with an ISSN, and has been archived and is available from the following digital repositories: PubMed Central, LOCKSS, Academia.edu and ResearchGate.

Taxonomic Treatment
Family Theraphosidae Thorell 1870. Diagnosis: Prolateral coxa I with a long paddle or spikeshaped seta aligned along the coxa and acting against numerous short transverse spiniform setae series on retrolateral surface of maxillae; also lyra similar to that (usually) on interface of coxae I and II or I-IV ( Figure 13); palpal femora with a distinct brush of setae on retrolateral face (in most genera) and two distinct mounds at labio-sternal grove (Raven 1985).
Distribution: Africa-Angola, Congo, Democratic Republic, Ethiopia, Gabon, Guinea, Kenya, Nigeria, Tanzania; Madagascar, Mauritius; United Arab Emirates-Yemen and associated gulf islands and India ( Figure 2) [31]. Diagnosis: males and females of Heterophrictus differ from those of other Theraphosidae genera (except for the Eumenophorinae & Theraphosinae Thorell, 1870) by possessing stridulatory setae between the coxae of legs I-II or I-IV (Fig. 13). It differs from Eumenophorinae genera by having the scopulae of tarsi of leg III and IV divided by a band of short spike setae instead of normal setae (Fig. 35) and possessing pilose as well as pyriform setae on prolateral coxa (Fig. 13). Differs from Theraphosinae in lacking urticating setae. Females differ from all other Eumenophorinae genera (except for Neoheterophrictus and Sahydroaraneus gen. nov.) by possessing rastellum on the prolateral border of chelicerae. Differs from Neoheterophrictus and Sahydroaraneus gen. nov. by lacking tibial spur, by having the tarsal scopulae of leg III-IV divided by a band of short spike setae and in the males possessing a cluster of spiniform setae on the retrolateral basal region of tibia I (Fig. 7). Females differ from Neoheterophrictus and Sahydroaraneus gen. nov. in possessing spermathecal stalks with equal width (diameter) throughout with a single lobe on each stalk (Fig. 3D) (vs. multi lobbed in Neoheterophrictus; spermathecal stalk broader at base, tapering at distal end bearing a bud like single lobe).
Description: Medium sized spiders 14-26. Carapace ovate, hirsute, with two clear (setae-less) bands on both sides of the caput. Caput low. Fovea slightly procurved. Eye group sub-quadrate to wider than long, ocular tubercle well defined. Clypeus narrow. Chelicerae normal, with 16-21 teeth on promargin of furrow, basomesally 24-50 small teeth. Rastellum in the form of small stout spines on the prolateral cheliceral border in females. Labium wider than long. Labiosternal grove shallow with two distinct mounds. Cuspules 25-30 in the sub-apical region of the labium. Maxillae longer than wide, overall setose, prolateral anterior angle distinctly produced, 100-150 cuspules distributed along proximal prolateral angle. Serrula absent. Sternum as long as wide, sigilla small oval, submarginal. Stridulatory setae below coxal suture with horizontally aligned thick pilose setae. Base of setae with fine lines on the surface eventually turns pilose in nature ( Fig. 13A-I). Below these are sparsely arranged thin pilose setae. Bellow suture with numerous vertically aligned pyriform setae ( Fig. 31-34). Pyriform setae gradually traosform into filiform setae ending in a curve ( Fig. 13F-G). Several short setae with scoop like tips intermixed with pyriform setae. Legs moderately stout, hirsute, spines present except on femora & coxa. Paired claws on legs without dentition (Fig. 14) and claw tufts well-developed. All tarsi with scopula, metatarsi with J scopulate. Abdomen hirsute, without pattern. PMS well-developed; PLS, apical segment digitiform. Males lack tibial apophysis. A cluster of spiniform setae present on the retrolateral basal region of the tibia I ( Fig. 7A-C). Palpal organ pyriform, with filiform embolus, ending in a scoop with a sharp tip, lacking keels. Spermathecae in the form of twin seminal receptacles with the apical end slightly bulbous and rounded. Remark: Detailed description provided by Guadanucci [19]. Diagnosis: Heterophrictus raveni sp. nov. males differ from Heterophrictus aareyensis sp. nov. by being larger in total length, by possessing stridulatory setae on coxae of all legs and having the same more elaborate in H. raveni sp. nov. The new species possesses more basosomal teeth as competed to H. aareyensis sp. nov. and PLE are placed in advance of the posterior border of PME giving it a procurved appearance (Fig. 45A).
Etymology: The new species is named in honor of Dr. Robert Raven from Queensland Museum, Australia for his immense contribution to the study of mygalomorph spiders of the world.
Sternum (Fig. 10B): longer than wide, high in center, slopping gradually, covered with short black setae. Posterior edge pointed but not separating coxa IV. Long and short bristles radiate from margin. Pedicel not clearly seen.
Natural history and distribution: A single male was found under a boulder during monsoon. Several female were found under boulders along a dry stream bed in a shallow depression without any webbing. Two females were found holding an egg cocoon each under the chelicerae in the month of May (Fig. 9B). The habitat at the type locality is of evergreen type and is contagious with the forests of Bhimashankar Wildlife Sanctuary. Sympatric theraphosid species observed include Plesiophrictus millardi.  Diagnosis: Heterophrictus aareyensis sp. nov. differs from H. raveni sp. nov. by being smaller in total length, by possessing stridulatory spiniform setae on the coxae of leg I-II only, in fewer basosomal teeth and by having posterior border of PLE & PME on the same plane (Fig. 39, 105). Females differ from H. raveni sp.
nov. in having the spermathecal stalk wider in diameter and in be short (Fig. 21D).
Etymology: The new species is named after Aarey where the type specimens was collected and also to seek attention of locals for conservation of the type locality.
Spike setae (Fig. 17C): a cluster of 10-12 spike setae present on basal region of retrolateral aspect of tibia of leg I.
Leg coxae: prolateral coxa of leg I & II with few horizontally aligned pilose setae below coxal suture; above with vertically aligned pyriform setae. Retrolateral face with long black bristles on dorsal retrolateral border. Coxal bases dorsally easily seen from above. Coxae, I-II sloping forward, III-IV sloping backward.
Scopulae: entire on tarsi I-II, tarsi III entire, divided by a band of 2-3 rows of spike setae; tarsi IV divided by a band of short spike setae.
Abdomen (Fig. 16A & B): cuticle not exposed dorsally and ventrally; covered with fine layer of dark brown setae intermixed with long silver setaes.
Scopulae: entire on tarsi I & II undivided, tarsi III divided by a band of 4-5 rows of short spike setae, tarsi IV divided by a band of 7-8 rows of short spike setae. Metatarsi I-IV undivided and J scopulate.
Natural history: The male holotype was found under a boulder close to human settlement in Aarey Milk Colony. The habitat at the collection site is highly degraded and is dominated by deciduous and exotic flora. The region is rich in its biodiversity but numerous threats from various anthropogenic activities are resulting in great loss to the habitat.  [14] and Siliwal et al. [5].

Heterophrictus blatteri
Remark: Gravely (1935) described Plesiophrictus blatteri from Satara district based on specimens of both sexes. Based on fresh collection from Satara district and also supported by Gravely's [8] description, P. blatteri males appear to possess cluster of spike setae on tibia of leg I, females possess rastellum on porolateral dorsal edge of the chelicerae and characteristic stridulatory setae between coxa of legs. This leads us to transfer P. blatteri to the genus Heterophrictus. Gravely [7] described P. sataraensis from the same district based on one male and several females. The male specimen BMNH 2205/17 shows all characteristic of the genus Plesiophrictus as prescribed by Sanap & Mirza [12] whereas female specimen (BMNH 16.5.2.15) from the type series possess rastellum (Fig. 24A) and possess characters seen in Heterophrictus blatteri. Hereby we conclude that only the male specimens of P. sataraensis be the representative of the species and the females of the type series be attributed to H. blatteri. Tikader [10]   Diagnosis: Neoheterophrictus males and females differ from all other genera known within the Theraphosidae (except for the Eumenophorinae & Theraphosinae) in possessing stridulatory setae between the coxae of legs I-II (Fig. 13). It differs from known genera within the Eumenophorinae in having the tarsi of leg IV divided by a band of short spike setae instead of normal setae (Fig. 35) and possessing pilose as well as pyriform setae on prolateral coxae. Differs from Theraphosinae in lacking urticating setae. Females differ from all other genera known within the     spines on prolateral cheliceral border in females ( Fig. 33 & 34). Labium wider than long. Labiosternal grove shallow with two distinct mounds at junction. Cuspules 33-45 in sub-apical region of labium. Maxillae longer than wide, slightly setose, prolateral anterior angle distinctly produced, 140-160 cuspules distributed along proximal prolateral angle. Serrula absent. Sternum as long as wide, sigilla small oval, submarginal. Stridulatory bristles above coxal suture with horizontally aligned thick pilose setae. Base of setae with fine lines on the surface eventually turns pilose in nature. Below these are sparsely arranged thin pilose setae. Bellow suture with numerous vertically aligned pyriform setae. Pyriform setae gradually transform into filiform setae ending in a curve. Several short setae with scoop like tips intermixed with pyriform setae. Legs moderately stout, hirsute, spines present except on femora. Paired claws on legs without dentition and claw tufts welldeveloped. All tarsi with scopulae entire and only of leg IV divided by a band of spike setae (Fig. 35), metatarsi with J scopulate. Abdomen hirsute, without pattern. PMS well-developed but small; PLS moderately long, apical segment digitiform. Males possess tibial apophysis composed of primary segment being thick and curved. Secondary segment of tibial apophysis in the form of a tubercle, with numerous erect spines upon it. Cluster of spiniform setae absent on retrolateral basal region of tibia I. Palpal organ pyriform, with embolus filiform, ending in a scoop with a sharp tip, lacking keels.
Neoheterophrictus Diagnosis: Males of Neoheterophrictus smithi sp. nov. differ from Neoheterophrictus amboli sp. nov. and N. sahyadri in possessing a long slender spine at the base of the primary tibial apophysis and in the tip of the primary tibial apophysis ending in a spine (Fig. 30-31).
Additionally the primary tibial apophysis curves at apex tapering gradually and lacks the sub-apical swelling present in N. amboli sp. nov. (Fig. 30-31). Neoheterophrictus smithi sp. nov. further differs from N. amboli sp. nov. in bearing many more basosomal teeth on chelicerae and also bearing spine of patella of leg IV. Differs from N. crurofulvus in possessing a long slender spine at the base of the primary tibial apophysis (Fig. 30-31). Female differ from those of N. uttarakannada in possessing lower cheliceral teeth count and in lacking 3-4 stiff bristles on the prolateral aspect of the chelicerae.
Etymology: The species epithet is in honor of Andrew M. Smith for his valuable contribution towards study of theraphosid spiders which enabled us to carry out the present study and his immense help to ZM & RS throughout their project.
Maxillae (Fig. 26B): 2.16 long in front and 2.34 in back, 1.28 wide; more than 156 cuspules arranged in an anterior corner in triangle region. Prolateral face with a few scattered short setaes below and above maxillary suture; retrolateral face smooth and glabrous, with horizontally aligned long bristles in basal region which act against numerous horizontally aligned spike setae on coxa I.   Sternum (Fig. 26B): longer than wide, high in center, slopping gradually, covered with short black setae. Posterior edge pointed but not separating coxa IV. Long and short bristles radiate from margin. Pedicel not clearly seen.
Scopulae: entire on tarsi I & II undivided, tarsi III divided by a band of 2-3 rows of short spike setae, tarsi IV divided by a band of 4-5 rows of short spike setae. Metatarsi I-IV undivided and J scopulate.
Tibial apophysis (Fig. 30-31): primary segment thick, curved at apex, tapers gradually into a spine. Primary segment reddish brown at base gradually turning black towards the distal portion. Secondary segment in tubercle form, bearing upon it numerous erect spines and a stout curved spine arises from its base which terminates in a blunt tip.
Maxillae (Fig. 32B): 2.12 long in front and 2.6 in back, 1.4 wide; more than 145 cuspules arranged in an anterior corner in triangle region. Prolateral face with a few scattered short setaes below and above maxillary suture; retrolateral face smooth and glabrous, with horizontally aligned long bristles in basal region which act against numerous horizontally aligned spike setae on coxa I. Labium (Fig. 32B): 0.7 long, 0.9 wide. ca. 45 cuspules in band for J of length anteriorly. Basal groove shallow and distinct, labiosternal groove concave with two distinct sigilla.
Leg coxae: prolateral coxa of all legs with numerous horizontally aligned pilose setae below coxal suture; above with vertically aligned pyriform setae. Retrolateral face with long black bristles on dorsal retrolateral border. Coxal bases dorsally seen from above. Coxae, I-II sloping forward, III-IV sloping backward, ventrally with short. Scopulae (Fig. 35): entire on tarsi I divided by 2-3 rows of short spike setae, tarsi II divided by 4-5 rows of short spike setae, tarsi III & IV divided by a band of 3-4 rows of short spike setae. Metatarsi I-II 2/3 scopulate and III-IV J scopulate and undivided.
Trichobothria: tarsi I, 16-18 clavate and 8-9 long and short filiform in distal half in two rows; tarsi II, 20-21 clavate and 8-9 long and short filiform in distal half in two rows; tarsi III, 9-10 clavate and 6-7 long and short filiform in distal half in two rows; tarsi IV, 2 clavate and 8-9 long and short filiform in distal half in two rows; palp tarsi with 22-23 clavate and 7-8 long and short filiform in distal half in two rows. Abdomen (Fig. 32): covered with a mat of short brown setae mixed with long gray setae lost after preservation rendering the cuticle entirely exposed dorsally.
Natural history and distribution: A single male specimen was found along a road under an Albizia saman tree in the night. The forest type in the area of evergreen type and revives heavy rainfall. The paratype female was found under a boulder in a shallow depression without any webbing. The female tried to escape as the rock was turned. Several more immature female specimens were encountered in the same area in a similar depression under boulders. This species is presently known only from the type locality which lies on the outskirts of Sharavati Wildlife Sanctuary and it is likely that this species will also be found there in addition to the type locality as the areas shares a similar biotope. Diagnosis: Neoheterophrictus amboli sp. nov. differs from N. smithi sp. nov. in possessing a distinct sub-apical swelling on the primary segment of tibial apophysis which abruptly terminates into a blunt tubercle. Further differs from N. smithi sp. nov. in possessing fewer cheliceral basosomal teeth. Differs from N. crurofulvus in possessing a long slender spine at the base of the primary tibial apophysis. Differs from N. sahyadri in possessing a stout and short spine on the secondary tibial apophysis (spine slightly longer and slender in N. sahyadr) (Fig. 41-42).
Etymology: Named after Amboli, where the holotype was collected. Amboli is treated as an invariable noun in apposition to the generic name.
Leg coxae: prolateral coxa of leg I & II with few horizontally aligned pilose setae below coxal suture; above with vertically aligned pyriform setae. Retrolateral face with long black bristles on dorsal retrolateral border. Coxal bases dorsally easily seen from above. Coxae, I-II sloping forward, III-IV sloping backward, ventrally with short.
Trichobothria: tarsi I, 11-12 clavate and 9-10 long and short filiform in distal half in two rows; tarsi II, 13-14 clavate and 11-12 long and short filiform in distal half in two rows; tarsi III, 16-17 clavate and 12-13 long and short filiform in distal half in two rows; tarsi IV, 14-15 clavate and 12-13 long and short filiform in distal half in two rows; palp tarsi with 22-23 clavate and 10-11 long and short filiform in distal half in two rows. Metatarsi I-II with 4-9, metatarsi III-IV with 9-10 long and short filiform. Tibia I-II with 4-6 and tibia III-IV with 5-8 long and short filiform. Palp tarsi with 20-21 clavate. Abdomen (Fig. 37): covered with a mat of short brown setae with numerous long gray setaes. Similar on the venter, however of the gray setae are sparse in distribution.
Tibial apophysis (Fig. 41-42): primary segment black thick, curved at apex and with a prominent bulge at sub apical region further transforming abruptly into a blunt tubercle. Secondary segment in tubercle form bearing numerous erect spines upon it and a stout curved spine arises from its base which terminates in a blunt tip.
Palp bulb (Fig. 39-40 Remarks: Presence of rastellum on the chelicerae (Fig. 44A), horizontally aligned stridulatory setae above maxillary suture (Fig. 44B) and multi-lobed spermathecae (Fig. 44C) suggests placement of this taxa in the genus Neoheterophrictus. The type series contains specimens from several localities which represent more than one species [14] which also appears to be a case with several species of this subfamily from India. Diagnosis: Sahydroaraneus gen. nov. males differ from all other genera known within the Theraphosidae (except for the Eumenophorinae & Theraphosinae) in possessing stridulatory setae between the coxae of legs I-II (Fig. 13). It differs from known genera within the Eumenophorinae in having the tarsi of leg IV divided by a band of short spike setae instead of normal setae (Fig. 35) and possessing pilose as well as pyriform setae on prolateral coxae. Differs from Theraphosinae in lacking urticating setae. Differs from Heterophrictus in possessing tibial spur (Fig. 48A-C), scopulae of leg III undivided and in lacking a cluster of spiniform setae on the retrolateral basal region of tibia I. Males of Sahydroaraneus gen. nov. closely resemble Neoheterophrictus but can be differentiated based on absence of secondary tibial apophysis and in the primary apophysis comprises of a basal stalk which gives rise to a thick long black spine terminating in a sharp tip (Fig. 48A-C). Sahydroaraneus gen. nov. males further differ from those of Heterophrictus and Neoheterophrictus in possessing thick black setae on the pro-dorsal edge of chelicerae whereas these setae are short thinner in the latter two (Fig. 46C). Sahydroaraneus gen. nov. females possess stouter and longer rastellum tooth as opposed to short small ones seen in other two Indian eumenophorine genera (Fig. 51A).
Etymology: The proposed generic name comprises of two words ''Sahydro'' referring to the Sahydri hills which is synonymous to the Western Ghats within which the type locality is located and the second word ''araneus'' refers to a spider in Latin. The generic name is treaded as masculine in gender.
Description: Small sized spiders 14.61. Carapace ovate, hirsute, with two clear (setae-less) bands on both sides of caput.
Caput low. Fovea slightly procurved. Eye group sub-quadrate to wider than long, tubercle well-defined. Clypeus narrow. Chelicerae normal, with 13 teeth on promargin of furrow, rastellum presein in females on the pro-dorsal edge. Labium wider than long. Labiosternal grove shallow with two distinct mounds at junction. Cuspules 33-45 in sub-apical region of labium. Maxillae longer than wide, slightly setose, prolateral anterior angle distinctly produced, 140-160 cuspules distributed along proximal prolateral angle. Serrula absent. Sternum as long as wide, sigilla small oval, submarginal. Stridulatory bristles above coxal suture with horizontally aligned thick pilose setae. Base of setae with fine lines on the surface eventually turns pilose in nature. Pyriform setae absent. Legs moderately stout, hirsute, spines present except on femora. Paired claws on legs without dentition and claw tufts welldeveloped. All tarsi with scopulae entire and only of leg IV divided by a band of spike setae (Fig. 74& 79), metatarsi with J scopulate. Abdomen hirsute, without pattern. PMS well-developed but small; PLS moderately long, apical segment digitiform. Males possess tibial apophysis composed of primary segment long, curved, of the same pigment as tibia, at its distal end gives rise to a long, thick black spine which ends in a sharp tip. Distinct collar like structure present at the base of the long spine. Secondary segment absent. A long spine present on the ventral aspect of the tibia close to the tibial apophysis. Cluster of spiniform setae absent on retrolateral basal region of tibia I. Palpal organ pyriform, with embolus filiform, ending in a scoop with a sharp tip, lacking keels. Spermathecae with single lobe on each stalk; stalk broader at base and tapers towards its distal end which gives rise to a single bud like lobe.
Sahydroaraneuss Diagnosis: A medium sized species in relation to members of this subfamily (14.61 mm); with ALE being the largest, posterior border of eyes on the same plane (Fig. 46A). Chelicerae with 13 promarginal teeth. Primary segment of tibial apophysis long, curved, of the same pigment as tibia, at its distal end gives rise to a long, thick black spine which ends in a sharp tip. Distinct collar like structure present at the base of the long spine. Secondary segment absent. A long spine present on the ventral aspect of the tibia close to the tibial apophysis (Fig. 48 A-C).
Etymology: The new species is named in honor of A. S. Hirst for his valuable contribution towards Arachnology.
Scopulae: tarsi I-III, entire and undivided; tarsi IV, entire, divided centrally with 3-4 row of spike setae. Abdomen (Fig. 49A-B): covered with a mat of short brown setae with numerous long gray setaes. Similar on the venter, however of the gray setae are sparse in distribution.
Tibial apophysis (Fig. 48A-C): primary segment long, curved, of the same pigment as tibia, at its distal end gives rise to a long, thick black spine which ends in a sharp tip. Distinct collar like structure present at the base of the long spine. Secondary segment absent. A long spine present on the ventral aspect of the tibia close to the tibial apophysis.
Palp bulb (Fig. 47A-C Remark: The type specimen appears to be an immature specimen as spermathecae cannot be seen (Fig. 51C) and stridulatory setae between the coxa of legs is not well developed (51B). But the specimen shows presence of distinctly stout and long rastellar teeth (Fig. 51A) unlike the short rastellar teeth seen in Heterophrictus and Neoheterophrictus. In addition to this, based on the proximity of the type locality of Plesiophrictus raja to that of Sahyroaraneus hirsti, we provisionally place it in the genus Sahydroaraneus until mature females and males of the species are examined.  Remark: Chelicerae possesses rastellum on its pro-dorsal edge, stridulatory setae present between coxa of legs peculiar to Eumenophorinae. Given that the spermathecae does not possess multiple lobes, it cannot be placed in the genus Neoheterophrictus. Heterophrictus appears to be restricted to the northern Western Ghats of Maharashtra and hence we provisionally place this species in the newly erected genus Sahydroaraneus until males from the type locality are examined.

Discussion
Mygalomorph spiders include trapdoor spiders, tarantulas, funnel web spiders and their kin, represented in 15 families that containing 326 genera and 2,780 nominal species including the present work [2,39]. Being an ancient monophyletic group mygalomorphs, which evolved nearly 300-250 MYA, [43] retain several characteristics that are considered primitive for spiders, e.g., chelicerae orientation, two pairs of book lungs, simple silk-  spinning structures, etc. Many mygalomorph taxa are dispersallimited and regionally endemic, and have long been favorites of biogeographers [39]. Considering the inability of most mygalomorph spider to disperse far distance with the exception of a few demonstrated using molecular data and opportunistic observations [44,45], they form a vital group for the study of evolutionary history as majority of the species are restricted in distribution. Africa, Madagascar, associated islands and India share many common mygalomorph elements, most of which are presently known only from the Western Ghats in India (Fig. 53) and in Sri Lanka [see 23,36]. Discovery of five new species of Eumenophorinae adds to growing evidence of past isolation in the biogeographical history of India. Interestingly, India shares several mygalomorph elements with its Mesozoic partner Madagascar and associated islands as opposed to absence of major groups of vertebrates, such as caecilians and representatives of the frog family Nasikabatrachidae, when evolutionary analyses indicate that they should have been there in the past [34]. Presently the following mygalomorph genera are common among Africa, India, Sri Lanka, Madagascar and associated Islands: Scalidognathus Karsch, 1891; Heligmomerus Simon, 1892; Idiops Perty, 1833; Tigidia Simon, 1892 [2,23,36,40,41]. Furthermore several subfamilies like Selenogyrinae and Eumenophorinae are distributed only in Africa and India. It is likely that many more Gondwanan  mygalomorph elements will be found in Indian in the long term with detailed studies which will enhance our understanding of the biogeography of this group. Immediate efforts should be made to document other mygalomorph spider in the Western Ghats especially with the help of molecular tools to help evaluate and conserve our evolutionary history.
We hypothesize that Heterophrictus, Neoheterophrictus and Sahydroaraneus gen. nov. form a separate clade within eumenophorinae sharing synapomorphy of lacking a brush of stiffened setae on the palp femur which is presumed to be lost in these genera, an uncommon character for the sub-family and in possessing rastellum. However, Indian genera possess stridulatory setae between the coxae of legs, well developed labio-sternal mounds, lacking urticating setae and tibial spur (in Neoheterophrictus and Sahydroaraneus) supporting their inclusion in the Eumenophorinae. Heterophrictus and Neoheterophrictus (likely Sahydroaraneus as well) possess additional characters like presence of rastellum, pilose and pyriform stridulatory setae between the coxae and lives in shallow depression under boulders without webbing, which make them unique among the Indian theraphosids. Males of Heterophrictus possess a cluster of spike setae on the retrolateral basal region of tibia I. These setae have thus far only been reported from this genus and not from any theraphosid genera in the world. The function of these setae at present remains unknown and further studies must be carried out to better understand this structure as it serves as an important taxonomic character.
Pocock [6] in his description of H. milleti mentions examination of immature specimens of nearly allied species from eastern Pune and Jauli in Satara district in western Mahatashtra. Later, a damaged female specimen from Panchagani, Satara district was identified by Gravely [8] to belong to the genus Neochilobrachyus Hirst, 1909. After having examined material from Satara district as well as those examined by Pocock [6], we here conclude that the species from Satara district belong to the genus Heterophrictus. Siliwal et al. [5] synonymized Heterophrictus mahabaleshwari ( = Plesiophrictus mahabaleshwari Tikader, 1977 with H. milleti based on similar spermathecael shape. We examined several specimens of Heterophrictus sp. from Satara district as well as material of H. milleti in the collection of NHM and conclude that the species are distinct. However, H. mahabaleshwari possesses character seen in females of H. blatteri and we here synonymize H. mahabaleshwari with H. blatteri given that 'blatteri' is the oldest available name. This indicates that the genus is at least widespread in the northern Western Ghats of Maharashtra (Fig. 54A). Sanap & Mirza [12]  transferred Plesiophrictus madraspatanus Gravely, 1935 to the genus Neoheteriphrictus based on morphology of the tibial apophysis which indicates that this genus too is widespread however fresh material from the type locality must be examined to ascertain its generic allocation. Neoheterophrictus is presently represented by seven species distributed in the Western Ghats from Southern Maharashtra to Tamil Nadu and one exception of a species from Chennai eastern Tamil Nadu. Gravely [7] described the males of Annandaliella travancorica and while doing so also noted that the males lack the characteristic intercheliceral peg setae seen in the genus Annandaliella. But he failed to examine presence of stridulatory setae between the coxa of legs. Based on present collection locality data, Sahydroaraneus appears to be distributed in Southern Indian states of Kerala and Tamil Nadu. Thus based on the available locality data, Neoheterophrictus is restricted to denser, moist evergreen forest in central Western Ghats (Fig. 54B) as opposed to mixed moist deciduous, semi-evergreen forest of Northern Western Ghats of Maharashtra and Sahydroaraneus gen. nov. is restricted to southern Western Ghats (Fig. 54C). The distribution of these three genera shows a clear pattern based on flora of Western Ghats [46] which in turn is influenced by formation of the Western Ghats.
The recent discovery of the new Eumenophorinae genus Neoheterophrictus and Sahydroaraneus gen. nov. possessing such distinct and unique characters of this Gondwanan sub-family which remained undescribed for so long highlights our lack of knowledge and dearth of work on this group. The present work also brings forth the problems with taxonomic research of Theraphosidae and in general mygalomorph spiders in India [see 11,12]. Thus dedicated surveys are needed to further enhance our knowledge of these spiders which will consequently enable us to contribute towards their conservation.