﻿Four new terrestrial earthworm species from the northeast Thailand (Oligochaeta, Megascolecidae)

﻿Abstract Earthworm specimens collected from Sakon Nakhon and Nakhon Phanom, northeast Thailand, were found to contain four new species in the family Megascolecidae, with one species in the genus Metaphire Sims & Easton, 1972, and the other three in the genus Amynthas Kinberg, 1867. These are herein named Metaphiresongkhramensis Chanabun & Panha, sp. nov. in the sexthecal houlleti species group, and Amynthassakonnakhonensis Chanabun & Panha, sp. nov., A.auriculus Chanabun & Panha, sp. nov., and A.bantanensis Chanabun & Panha, sp. nov. in the sexthecal aelianus species group. Metaphiresongkhramensis Chanabun & Panha, sp. nov. occurs in dark clay soil of the oxbow lake of the river, Amynthassakonnakhonensis Chanabun & Panha, sp. nov. occurs in wetland area, A.auriculus Chanabun & Panha, sp. nov. occurs in dark sandy loam habitats of mixed deciduous forest while the following species, A.bantanensis Chanabun & Panha, sp. nov. occurs in sandy loam habitats of paddy fields. Descriptions of the new species, including illustrations of the external and internal morphological characteristics, are provided.


Introduction
Earthworms are common macro-soil invertebrates found in almost all parts of the world, in all types of habitats, such as terrestrial, aquatic, and semi-aquatic habitats.Earthworms play significant roles in the physical, chemical, and biological properties of soil (Edwards and Arancon 2022).As permanently soil-dwelling animals, their activities affect soil properties and create suitable habitats for other smaller soil flora and fauna.Moreover, earthworms can be used as bioindicators of the relative health of soil ecological systems (Fründ et al. 2011).There are approximately 6,000 species that have been recorded worldwide, and the estimated total global species

Material and method
Earthworm specimens from Kong Ngong from Sakon Nakhon were collected with the villagers at approximately 2.00-5.00a.m. by hand when earthworms were crawling on the soil surface during the cold season (November).Specimens from Nong Tuet and Wut Tham Kham from Sakon Nakhon and Ban Tan from Nakhon Phanom were collected by digging and hand-sorting.All earthworm specimens are from northeastern Thailand (Fig. 2).The collected specimens were washed and killed in 30% (v/v) ethanol before being photographed and then transferred to 95% (v/v) ethanol for preservation and subsequent morphological studies.The anatomical and morphological observations were made with an ACCU-SCOPE 3075 stereo microscope.Illustrations included the body segments, distinct external characters, and internal organs.The type series are Figure 2. Map of the collecting localities of the new species described in this paper from northeast Thailand.Filled circle: Metaphire songkhramensis sp.nov.from Kong Ngong, Akat Amnuai, Sakon Nakhon, Thailand.Filled triangular: Amynthas sakonnakhonensis sp.nov.from Nong Tuet, Samakkee Pattana, Akat Amnuai, Sakon Nakhon, Thailand.Filled square: Amynthas auriculus sp.nov.from Wut Tham Kham, Phannanikom, Sakon Nakhon.Filled star: Amynthas bantanensis sp.nov.from Ban Tan, Nawah, Nakorn Phanom, Thailand.deposited in Chulalongkorn University, Museum of Zoology, Bangkok, Thailand (CUMZ).Additional paratypes will be deposited in the Natural History Museum (NHMUK), London, and at the Biozentrum Grindel und Zoologisches Museum, University of Hamburg (ZMH).Specimens used in this study strictly followed the protocols approved by the Institutional Animal Care and Use Committee of Khon Kaen University (IACUC-KKU) under approval number IACUC-KKU-32/65.
Description of holotype.Length 333 mm, diameter 12 mm, cylindrical body with 167 segments.Preserved specimens are dark brownish on the dorsal part and pale gray on the ventral part.Setae regularly distributed around segmental equators, numbering 65 at segment VII, 85 at segment XX, and nine between male pores at segment XVIII.Setal formula AA:AB:ZZ:ZY=1:1:2:1 at segment XIII.Single female pore on the ventral side at segment XIV.Prostomium epilobic.First dorsal pore in 12/13.Clitellum annular in XIV-XVI with no dorsal pores or setae.
Male pores in copulatory pouches that have wrinkled and convex margins on ventrolateral sides of segment XVIII; pouches 5 mm apart, which is 0.13× the body circumference.These pores are large, conspicuous, deep holes that resemble eyes.There is no skin folding, and genital markings absent.Large spermathecal pores arranged in three pairs in ventral region 6/7-8/9, distance between each pair is ~ 0.26× the body circumference ventrally apart.There are no genital markings in this area.
The septa at 5/6-7/8 thick, absent in 8/9-9/10, slightly thick in 10/11-11/12, thin in 12/13-14/15, and very thin behind 15/16.Intestine begins at segment XV. Gizzard large within IX-X.Long and simple intestinal caeca in XXVII-XIX.Esophageal hearts four pairs in X-XIII.Holandric; testes and funnels in segments X and XI.Seminal vesicles are paired, one at XI-XII, the other at XIII-XIV; the hindmost pair is larger.Prostate glands large, located in segments XV-XXII, and divided into several lobules.Prostate duct long, slender with U-shape, and with large paired glandular masses on the copulatory sac at segments XVII-XVIII and XIX-XX.
The ovaries are located in segment XIII.Three pairs of spermathecae present on VII-IX.Ampulla large, round, and flat-shaped, with long and thick duct that can be clearly seen from the ampulla.Diverticulum is thin, long, and zigzagged towards the distal end.
Etymology.This new species was named after its type locality, Songkhram River.Distribution.This species is known only from the type locality.
Remarks.Metaphire songkhramensis is a new species of sexthecal earthworm without postclitellar genital markings.It has three pairs of spermathecal pores in intersegmental furrows 6/7-8/9.This species keys to the houlleti species group, which has more than 40 species (Sims and Easton 1972).Below, comparison of the new species with other species found in different regions in the houlleti species group: M. umbraticola (Gates, 1932) and M. quadrigemina (Gates, 1932) from Myanmar, M. amplectens (Michaelsen, 1934), M. dawydovi (Michaelsen, 1934) Metaphire songkhramensis sp.nov.similar to M. bindjeyensis from Sumatra in body size length but M. bindjeyensis obclavate ampullae with zigzag diverticulum, while the new species has a large, round, and flat-shaped ampulla with a thin, long, and zigzagged diverticulum.Metaphire songkhramensis sp.nov.differs from M. hijauensis from Malysia by the latter species has a smaller size than the new species (body size range 66-87 mm, diameter of 2.8-3.1 mm, with 101-120 segments), and the first dorsal pores in 10/11 while the new species has first dorsal pores in 12/13.
In Thailand, five species have been reported, M. houlleti (Perrier, 1872), M. virgo (Beddard, 1900), M. perichaeta (Beddard, 1900), M. khaochamao Bantaowong &Panha, 2016, andM. khaoluangensis Bantaowong &Panha, 2016.Metaphire songkhramensis sp.nov.can be distinguished from this group of five as follows: M. houlleti and M. virgo have first dorsal pores in 11/12 while the new species has first dorsal pores in 12/13, and a large, round, and flatshaped ampulla with a thin, long, and zigzagged diverticulum (spherical and small sac in M. houlleti and M. virgo, respectively).The new species does not have the contorted diverticulum stalk enveloped in connective tissue as found in M. houlleti, and also lacks the typhlosole present in M. houlleti.Metaphire virgo has a spermathecal diverticulum stalk with multiple folds, while the new species is absent.Metaphire houlleti and M. virgo have genital markings bearing stalked glands in association with spermathecae and copulatory sacs, while the new species lacks them.This new species differs from M. perichaeta in that M. perichaeta has a smaller size, inverted pear-shaped spermathecae with coiled diverticulum, and the last hearts in XII (Beddard 1900;Stephenson 1932).Metaphire songkhramensis sp.nov.differs from M. khaochamao and M. khaoluangensis, through the male opening, body size, and spermathecae.Metaphire khaochamao has smaller body size (body size range 100-148 mm, with 110-120 segments), the male field including the lateral slits associated with the male pores, the absence of setae between male pores, and an elliptic ampulla with a short duct.Metaphire khaoluangensis has smaller body size (body size range 130-265 mm, with 113-131 segments), a secondary male opening with puckered margin, an elongate ampulla, and a sac-like duct, whereas the new species has a larger size with setae between male pore, a large, round, and flat-shaped ampulla, and a thin, long, and zigzag diverticulum.A comparison of characters between M. songkhramensis sp.nov.and other related species is presented in Table 1.
Diagnosis.Medium-large size, length 134-238 mm, diameter 6-9 mm, 85-162 segments.Male pores paired in segment XVIII, each surrounded by four genital markings.Paired spermathecal pores in intersegments 6/7-8/9.Spermathecae large oval sacs of the ampulla, with stout and short duct, it is less than ampullar in length.Diverticulum long and zigzagged at the beginning and dilated towards the distal end, a baton-like chamber.Intestinal origin at XV. Intestinal caeca simple.Holandric.First dorsal pore in 12/13.Prostate glands large in segments XV-XXII, its ducts long and slender, surrounded by a large, long sessile glandular mass on the body wall.
Description of holotype.Length 217 mm, diameter 9 mm, body cylindrical with 156 segments.Preserved specimens are dark brownish on the dorsal  (Beddard, 1900) are from Bantaowong et al. (2016), M. houlleti (Perrier, 1872) are from Gates (1972), and M. virgo (Beddard, 1900) are from Stephenson (1932).prostate glands are well developed, located in XV-XXII, and divided into several lobules.The prostate duct is long and slender, surrounded by a large, long sessile glandular mass on the body wall on segments XVII-XIX.

Characters
Ovaries located in segment XIII.Three pairs of spermathecae present on VII-IX.Spermathecae large oval sacs of the ampulla, with stout and short duct, it is less than ampullar in length.Diverticulum long and zigzagged at the beginning and dilated towards the distal end, a baton-like chamber.
Etymology.The name sakonnakhonensis was derived from the province Sakon Nakhon.
Distribution.This species is known only from the type locality.
The aelianus species group consists of more than 60 species (Sims and Easton 1972;Tsai et al. 1999Tsai et al. , 2010;;Shen et al. 2003;James et al. 2005;Blakemore 2011;Bantaowong et al. 2014).In the following, we compared the new species with regional species in the aelianus species group: A. osmastoni (Michaelsen, 1907)  Amynthas sakonnakhonensis sp.nov. is similar to A. osmastoni from Myanmar and A. burchardi from Sumatra in the body size, but its easily distinguished by the new species having no median genital markings on segment VIII while A. osmastoni has them, the new species having no mid-ventral group of small circular papillae on segment XVIII while A. burchardi has them.Amynthas sakonnakhonensis sp.nov.can be distinguished from A. monsoonus and A. huangi from Taiwan in that the new species has a larger body size than these two species, A. monsoonus has genital markings in segments VII-IX.Amynthas monsoonus and A. huangi have no genital markings in the male pores region, whereas the new species contains these characters.
In Thailand, only four species within this species group have been reported from northeastern Thailand.These are A. fucosus (Gates, 1933), A. siam Blakemore, 2011, A. arenulus Bantaowong & Panha, 2014, A. longicaeca Bantaowong & Panha, 2014.Amynthas sakonnakhonensis sp.nov. is easily distinguished from A. fucosus from Burma and A. siam from Thailand because these species have body diameters of 6 mm and 3 mm, respectively, while the new species are wider at ~ 8-10 mm.Amynthas fucosus has two pairs of genital markings at 17/18 and 18/19, and A. siam has a single pair between the male pores, while the new species has four genital markings surrounded by male pores.This new species differs from A. arenulus in that the latter has a larger size and lacks genital markings in the male pore area.Amynthas arenulus has a large transverse elliptical disc surrounded by an elevated rim with an indistinct male aperture located at the outer edge of each poropore, while the new species has four genital markings surrounding the male pore area.The new species has body dimensions similar to A. longicaeca but can be distinguished from A. longicaeca by the fact that A. longicaeca has small crescent-shaped genital markings in the male pore region and spermathecae consist of large oval ampullar with short duct, diverticulum has a small ovate knob and nephridia are present on diverticulum, while the new species has none of these characters.Amynthas sakonnakhonensis sp.nov. is similar to A. bantanensis sp.nov. in body size but can be distinguished by the A. sakonnakhonensis sp.nov.having large oval sacs of the ampulla, with stout and short duct, with long and zigzag diverticulum, and has large, long sessile glandular mass on the body wall region of XVII-XIX, as opposed to A. bantanensis sp.nov., which has elongated sacs of the ampulla with slender and long stalks, and has no such glandular mass.Amynthas sakonnakhonensis sp.nov.differs from A. auriculus sp.nov.by the latter has a bit larger size, male pores located in between small three genital markings, each male pore region somewhat ear-shaped after fixation, and consists of a large, elongated ampullar with very short and zigzag diverticulum; however, A. sakonnakhonensis sp.nov.has four genital markings surrounding the male pore area, and has a large oval sacs of the ampulla, with long and zigzag diverticulum.Amynthas sakonnakhonensis sp.nov.different genital marking pattern from the other new Amynthas species here, and the other related species is presented in Table 5.  3, 5 Type material.Holotype: Adult specimen (CUMZ 3825) Wut Tham Kham, Phannanikom, Sakon Nakhon, northeast of Thailand, 17°13'06.2"N,103°54'00.7"E,403 m a.m.s.l., 9 October 2019, coll.R. Chanabun, A. Aoonkum.Paratypes: 2 adults (CUMZ 3826), 2 adults (NHMUK), same collection data as for holotype.

Amynthas auriculus
Diagnosis.Medium-large size, length 184-267 mm, diameter 9-11 mm, 95-151 segments.Paired male pores at segment XVIII, surrounded by three genital papillae, each male pore region somewhat ear-shaped after fixation.Paired spermathecal pores in intersegments 6/7-8/9.Spermathecae are large, elongated sacs, with slender stalks of the ampulla, and diverticulum very short and zigzagged from its origin until the end.Holandric.Intestinal caeca simple.First dorsal pore in 12/13.Prostate glands large in XVI-XXIV, the prostate duct large, slender, smooth, and a bit zigzagged at the end, surrounded by a large sessile glandular mass on the body wall.
Description of the holotype.Length 267 mm, diameter 10 mm, body cylindrical.139 segments.Preserved specimens are dark brownish on the dorsal part and pale gray on the ventral part.Setae are regularly distributed around segmental equators, numbering 27 at segment VII, 62 at segment XX, and 20 between male pores at segment XVIII.Setal formula AA:AB:ZZ:ZY = 1:1:2:1 at XIII.At segment XIV, a single female pore mid-ventrally.Prostomium epilobic.First dorsal pore in 12/13.Clitellum annular in segments XIV-XVI with no dorsal pores or setae.
Male pores paired, superficial, convex, located on ventral side of segment XVIII, in between small genital markings; each male pore region somewhat earshaped after fixation in ethanol.Male pores ~ 7 mm apart, distance 0.29× the body circumference.Single female pore at XIV.At segment XVIII, each male pore is lined by two anterior genital markings above the setal line, and one posterior genital marking below the setal line.Spermathecal pores three pairs in 6/7-8/9, distance between each pair is ~ 0.37× the circumference ventrally, there are no genital markings in this area.
The septa are thick in 5/6-7/8; absent in 8/9-9/10; slightly thick in 10/11-11/12; thin in 12/13-14/15; and very thin behind 15/16.Gizzard large at IX-X.Intestine begins at segment XV.Long and simple intestinal caeca in XXVII-XXI.Esophageal hearts four pairs in segment X-XIII.Holandric; testes and funnels in X and XI.Seminal vesicles paired in XI-XII.Prostate glands divided into several lobules, in XVI-XXIV, large and well-developed.Prostate duct large, slender, smooth, and a bit zigzagged, surrounded by a large sessile glandular mass on the body wall on segments XVIII-XXI.
Ovaries in segment XIII.Three pairs spermathecae in VII-IX.Spermathecae large, elongated sacs with slender stalks of the ampulla, diverticulum very short and zigzagged from its origin until the end.
Variation.Four paratypes range in size from 184-224 mm (218.20 ± 30.80 mm) body length with 95-151 (128.40 ± 22.65) segments (Table 3).Etymology.The species was named after the region of the male pore that looks like an ear after being preserved.
Distribution.This species is known only from the type locality.
Remarks.Amynthas auriculus sp.nov.belongs to the aelianus species group.This new species is quite similar to A. osmastoni from the South Andaman Islands and A. burchardi from Sumatra in the body dimensions but differs in having genital markings in the male pore area and having large sessile glandular masses on the body wall in XVIII-XXI, while A. osmastoni has genital markings in the spermathecal pores region without glandular masses on the body wall, and A. burchardi has a group of circular papillae in mid-ventral XVIII with no glandular masses on the body wall.Amynthas auriculus sp.nov.can be distinguished from A. monsoonus and A. huangi from Taiwan in which the new species has a larger body size, A. monsoonus has a body size of 102 mm, a diameter of 3.6 mm, with 83 segments and genital markings in segments VII-IX, while the new species is absent.Amynthas huangi has a body size of 70 mm, a diameter of 3.5 mm, with 101 segments, and genital marking glands in the body wall in VI-IX, while the new species has no such character.Amynthas monsoonus and A. huangi have no genital markings in the male pores region, whereas the new species is present.
Amynthas auriculus sp.nov. is easily distinguished from the other four earthworms of the aelianus species group reported from Thailand, namely A. fucosus from Myanmar, A. siam from Thailand, by its size and other physical traits.Amynthas fucosus has a body size range of 120 mm with a diameter of 6 mm and 114 segments, A. siam has a body size range of 73 mm, diameter of 3 mm, while the new species has a body size that ranges from 184-267 mm with a diameter of 9-11 mm, and 95-151 segments.Amynthas fucosus has two pairs of genital markings at 17/18, 18/19, and A. siam has single pair between the male pores, while the new species has three genital markings in the male pores.This new species differs from A. arenulus in that A. arenulus has no genital markings.In contrast, the new species has them at segment XVIII, near the male pores area.The new species is relatively similar to A. longicaeca in body size; however, A. longicaeca differs in that it has an oval ampulla, a small ovate knob with nephridia on the diverticulum, and also has a crescent-shaped male pore region (Table 5).4, 5 Type material.Holotype: Adult specimen (CUMZ 3827) Ban Tan, Nawah, Nakhon Phanom, northeast of Thailand, 17°30'28.0"N,104°05'48.0"E,149 m a.m.s.l., 28 September 2018, coll.R. Chanabun, A. Aoonkum.Paratypes: 3 adults (CUMZ 3828), 2 adults (NHMUK); same collection data as for holotype.
Male pores paired on the ventral side of XVIII, ~ 9 mm apart, distance 0.32× body circumference.Male pores superficial, convex, each surrounded by four genital markings.Spermathecal pores three pairs in 6/7-8/9.The distance between each pair is ~ 0.41× the body circumference ventrally apart.There are no genital markings in this area.Amynthas bantanensis sp.nov.differs from A. arenulus from Surin, Ubon Ratchathani, and Srisaket in that A. arenulus has a large transverse elliptical disc surrounded by an elevated rim with an indistinct male aperture located at the outer edge of each poropore and consists of a large sessile glandular mass on the body wall in this region, while the new species has genital markings at segment XVIII, near the male pore, but has no glandular mass on the body wall.Amynthas bantanensis sp.nov. is easily distinguished from A. fucosus from Burma and A. siam from Thailand because both previously reported species have smaller body sizes (A.fucosus = 6 mm, A. siam = 3 mm).Amynthas fucosus has two pairs of genital markings at 17/18, 18/19, and A. siam has a single pair between the male pores, while the new species has four genital markings surrounded by male pores at segment XVIII.The new species, Amynthas bantanensis, is similar body dimensions to A. longicaeca from Chaiyaphum, but is easily distinguished by A. longicaeca having crescent-shaped genital markings and a large sessile glandular mass on the body wall, while the new species lacks it.Considering the differences between A. bantanensis sp.nov., A. auriculus sp.nov., and A. sakonnakhonensis sp.nov.see the respective remarks sections above and Table 5.

Discussion
The benefits of earthworms have led to a variety of uses, such for decomposing organic waste from agriculture and households, as well as to enhance soil qualities and structure (Alegre et al. 1996;Sharma et al. 2017) and produce the best compost for plant growth and organic farming systems (Rajiv et al. 2009).Moreover, earthworms are used as food for animals.In some local areas, they serve as human food and a component of herbal medicine since the earthworm's tissue is rich in nutrients and enzymes that are very good for health (Grdiša et al. 2013;Sun and Jiang 2017), as mentioned in the introduction section.
In this paper, four new earthworm species are reported: one species of genus Metaphire and three species of genus Amynthas, of which three species were collected by locals and dried for sale (Metaphire songkhramensis sp.nov.from Sakon Nakhon, Amynthas sakonnakhonensis sp.nov.from Sakon Nakhon, and Amynthas bantanensis sp.nov.from Nakhon Phanom).Metaphire songkhramensis sp.nov.belongs to the houlleti species group.This new species has the longest and widest body size among the houlleti groups reported in Thailand.Amynthas sakonnakhonensis sp.nov., A. auriculus sp.nov., and A. bantanensis sp.nov.are classified in the aelianus species group.All of these new species were reported from northeast Thailand and collected from different habitat types.
Metaphire songkhramensis sp.nov.lives in the dark clay soil of the oxbow lake of the Songkhram River, which locals call Kud Klong Ngong.This habitat is covered with plenty of earthworm casts and with mainly small bamboo (Bambusa sp., Bambusa arundinacae Wild.), small shrubs (Hymenocardia wallichii Tul. and Euryeoma longifolia Jack.), and trees (Syzygium cumini L. and Lagerstroemia calyculata Kurz.).The earthworms move around on the soil, but, interestingly, all of them are the same species.
On the other hand, Nong Tuet, Sakon Nakon, from where Amynthas sakonnakhonensis sp.nov.was found, is a wetland.Water will flood in the rainy season and be covered by grass in the dry season.Villagers in the area use it as a pasture for livestock, such as cows and buffaloes.This habitat's soil is a mixture of clay and tiny pebbles, and the land could not be utilized for cultivation because shrubs predominate the area.The authors found that the new species of earthworms inhibit this area together with M. peguana (Rasa, 1890) and Drawida sp.
Amynthas auriculus sp.nov.lives in dark sandy loam soil covered with a mixed deciduous forest at Wut Tham-kham, Sakon Nakon.This area is a fertile forest of the Phu Phan Mountain range.Contrastingly, Amynthas bantanensis sp.nov.lives in the sandy loam of the soil covered with casts.This species was collected early in the morning from the field where rice and other economic plants are cultivated.
Furthermore, after interviewing the locals, the authors learned that every August to December of the year, from the end of the rainy and cold seasons (temperature ranges from 16-22.9 °C), earthworms come out from the soil at approximately 2:00-5:00 a.m.At this time the locals collect them for sale.If the weather is excellent, 30-80 kg/person of earthworms can be collected, but if it is otherwise rainy, very cold, or windy, the earthworms do not come out.Moreover, these earthworms also choose to stay underground during the full moon.

Figure 1 .
Figure 1.Collecting earthworms in the early morning of the winter season A villagers in Sakon Nakhon collect the migratory earthworms with their bare hands B large numbers of caught earthworms being sold to middlemen C Metaphire songkhramensis sp.nov.from Akat Amnuai, Sakon Nakhon, moving on the soil during the migration season, and D dried earthworms.

Figure 3 .
Figure 3. Photographs showing the A type locality of Metaphire songkhramensis sp.nov.from Kong Ngong, Akat Amnuai, Sakon Nakhon, Thailand B habitat of the new species covered with small bamboo and small shrubs C casts of the new species, and D coloration of newly collected paratype (CUMZ 3822) after the first preservation step in 30% (v/v) ethanol.

Figure 4 .
Figure 4. External and internal morphology of Metaphire songkhramensis sp.nov., holotype (CUMZ 3821) A external ventral view B internal dorsal view, and C spermatheca with location of spermathecal pore arrowed.

Figure 5 .
Figure 5. Photographs showing the A type locality of Amynthas sakonnakhonensis sp.nov.from Nong Tuet, Samakkee Pattana, Akat Amnuai, Sakon Nakhon, Thailand B living specimen under the stone near casts C coloration of a living paratype, and D coloration of a newly collected paratype (CUMZ 3824) after the first preservation step in 30% (v/v) ethanol.

Figure 6 .
Figure 6.External and internal morphology of Amynthas sakonnakhonensis sp.nov., holotype (CUMZ 3823) A external ventral view B internal dorsal view, and C spermatheca with location of spermathecal pore arrowed.

Figure 7 .
Figure 7. Photographs showing the A type locality of Amynthas auriculus sp.nov.from Wut Tham Kham, Phannanikom, Sakon Nakhon, Thailand B casts of the new species C coloration of a living paratype, and D coloration of a newly collected paratype (CUMZ 3826) after the first preservation step in 30% (v/v) ethanol.

Figure 8 .
Figure 8. External and internal morphology of Amynthas auriculus sp.nov., holotype (CUMZ 3825) A external ventral view B internal dorsal view, and C spermatheca with location of spermathecal pore arrowed.

Figure 9 .
Figure 9. External and internal morphology of Amynthas bantanensis sp.nov., holotype (CUMZ 3827) A external ventral view B internal dorsal view, and C spermatheca with location of spermathecal pore arrowed.

Table 2 .
Holotype and paratype dimensions and other morphological characteristics of Amynthas sakonnakhonensis sp.nov.

Table 3 .
Holotype and paratype dimensions and other morphological characteristics of Amynthas auriculus sp.nov.

Table 4 .
Holotype and paratype dimensions and other morphological characteristics of Amynthas bantanensis sp.nov.

Table 5 .
Morphological characteristics of A. sakonnakhonensis sp.nov., A. auriculus sp.nov., A. bantanensis sp.nov., and other aelianus species in Thailand, Burma, Sumatra.The comma is used to separate body length and width.Missing data are shown with a question mark (?).Data for A. arenulusBantaowong & Panha, 2014, A. longicaeca