On the occurrence of two species of striped Ichthyophis Fitzinger , 1826 ( Amphibia : Gymnophiona : Ichthyophiidae ) from Mizoram , India

The occurrence of 2 ichthyophiid caecilians, Ichthyophis khumzhi Kamei, Wilkinson, Gower & Biju, 2009 and Ichthyophis moustakius Kamei, Wilkinson, Gower & Biju, 2009 in the state of Mizoram in northeast India is reported for the first time. These records significantly increase the known distribution range of these striped forms of Ichthyophis which were previously known only from their type localities in the state of Manipur.


Introduction
Ichthyophiid caecilians from India are represented by 2 constituent genera-Uraeotyphlus Peters, 1880 which is restricted in distribution to the South Western Ghats and Ichthyophis Fitzinger, 1826 which is more widespread, inhabiting the mesic regions of peninsular India and the northeastern states (Gower et al. 2002, Wilkinson et al. 2007, Kamei and Biju 2016).Members of the genus Ichthyophis are provisionally divided into 2 non-monophyletic groups based on the presence or absence of a yellow lateral stripe which serves as a useful diagnostic character (Gower et al. 2002, Wilkinson et al. 2007).They are represented by 14 extant species in India out of which only 2 (I.sikkimensis Taylor, 1960 andI. bombayensis Taylor, 1960) are unstriped forms.
All recently described species of Ichthyophis from the northeastern states of India are known hitherto only from their respective type localities (Mathew and Sen NOTES ON GEOGRAPHIC DISTRIBUTION 2009, Kamei et al. 2009)).Herein, we report the first records of I. khumzhi from Saiha district (22°22ʹ28.0ʺN, 092°56ʹ06.1ʺE) and I. moustakius from Sawleng Village in Aizawl district (23°58ʹ40.6ʺN, 092°55ʹ35.4ʺE) from the state of Mizoram.

Methods
We studied a collection of 22 specimens of striped form Ichthyophis spp.from Mizoram, India, collected over a period of 2 years from 2008 to 2010.Specimens were collected in accordance with permit number A.33011/2/99-CWLW/225 issued by the Chief Wildlife Warden, Environment, Forest and Climate Change Department, Government of Mizoram, India.These specimens were fixed in a 4% formaldehyde solution for 2 days, washed and transferred for preservation in 70% ethanol.All specimens have been deposited in either the Bombay Natural History Society (BNHS) or at the National Centre for Biological Sciences (NCBS), Bangalore, India.
All measurements were taken to the nearest 0.1 mm using a Mitutoyo TM dial vernier caliper except total length, which was measured using a thread and a ruler scale.The following abbreviations for external morphological characters were adopted for the sake of brevity (Table 1): AG = number of annular grooves counted dorsally; TL = total length; CM = corner of mouth; TN = distance between tentacle and nare (TN); TE = distance between tentacle and eye (TE); C1 = length of the first collar; C2 = length of the second collar.

Results
The descriptions and identification of all the nominate species of Ichthyophis from northeast India have thus far been solely based on morphological characters (Taylor 1960, Pillai and Ravichandran 1999, Mathew and Sen 2009, Kamei et al. 2009).Our morphological analyses of freshly collected specimens from Mizoram reveal the occurrence of at least 2 distinct species.Two specimens used in our study were identified as I. khumzhi and 2 more as I. moustakius.The other specimens could not be diagnosed with certainty based on our current understanding of the taxonomy and distributions of Ichthyophis spp.from northeast India.While I. khumzhi is distinct from all its northeast Indian congeners in terms of the number of annular grooves counted dorsally (AG), I. moustakius differs from the rest in possessing a unique moustachelike arched yellow stripe that extends beyond its tentacles coupled with the number of annular grooves on its body (Kamei et al. 2009).All nomenclature herein follows the taxonomy suggested by Kamei et al. (2009).
Both I. khumzhi and I. moustakius are distinguished from I. sikkimensis by the presence of a yellow lateral stripe.
The lack of fine-scale sampling efforts and genetic data combined with a paucity of robust morphological characters for Ichthyophis from northeastern inhibit our ability to identify the other specimens in our collection from Mizoram.Kamei et al. (2009) described I. khumzhi based on 3 specimens collected from a single locality.We observed numerous specimens in our collection with the characteristic V-shaped head, coupled with a few other morphological characters, descriptive of I. khumzhi.However, the AGs of these specimens do not conform to the range published for I. khumzhi (364-396 vs 341-362).Similarly, Kamei et al. (2009) described I. moustakius with 238-268 AGs in their summary table, but their morphology datasheet includes 2 specimens (out of eight) with 272 and 292 AGs respectively.Taking a conservative approach, we employed the narrower AG range to diagnose I. moustakius, thereby excluding a lot of possible conspecifics from the scope of this report.

Discussion
The reports of I. khumzhi and I. moustakius present new state records for Mizoram.They also extend the geographical distribution range for I. khumzhi by 280 km and that of I. moustakius by 125 km south of their type localities (Fig. 2).All ichthyophiid species from northeastern India are categorized as Data Deficient or are not assessed (IUCN 2016).A comprehensive study employing molecular and morphological analyses of  these cryptic amphibians would go a long way in helping assess their diversity, distribution and conservation statuses with better accuracy.

Figure 2 .
Figure 2. Map showing new localities for Ichthyophis khumzhi (blue triangle) and I. moustakius (blue square) and their type localities (black triangle and black square, respectively).The outline of the state of Mizoram is highlighted.

Table 1 .
Measurements (in mm) and meristic data for the specimens from Mizoram.Abbreviations as mentioned in materials and methods.
* Measurement inaccurate or unavailable due to damage to the specimen.