Metaphire houlletoides, Nguyen & Nguyen & Lam & Nguyen, 2020

Nguyen, Tung T., Nguyen, Nam Q., Lam, Dang H. & Nguyen, Anh D., 2020, Six new species of the genus Metaphire Sims & Easton, 1972 (Annelida: Oligochaeta: Megascolecidae) from southeastern Vietnam, Raffles Bulletin of Zoology 68, pp. 220-236 : 232-234

publication ID

https://doi.org/ 10.26107/RBZ-2020-0019

publication LSID

lsid:zoobank.org:pub:650E406A-6668-42DE-B6A6-637B154A10FE

persistent identifier

https://treatment.plazi.org/id/15DB3703-FE70-4AED-AF0B-F7FDD2FBE9ED

taxon LSID

lsid:zoobank.org:act:15DB3703-FE70-4AED-AF0B-F7FDD2FBE9ED

treatment provided by

Carolina

scientific name

Metaphire houlletoides
status

sp. nov.

Metaphire houlletoides , new species

( Figs. 1 View Fig , 7 View Fig )

Material examined. Holotype: 1 mature ( CTU-EW.180. h01), secondary forests (11°28′07.2″N, 107°00′03.7″E), 145.7 m, Tan Hung commune, Dong Phu District , Binh Phuoc Province, 24 October 2017, coll. Luong Thi Huynh Tien. GoogleMaps Paratypes: 3 matures ( CTU-EW.180.p02), same data as holotype GoogleMaps .

Diagnosis. Body cylindrical, small-sized; length 50.2–76.5 mm, average diameter 1.0– 2.4 mm. First dorsal pore in 11/12. Prostomium epilobous. Two pairs of spermathecal pores in ventrolateral intersegments 7/8/9. Male pores deeply located inside copulatory pouches in the setal ring xviii. Genital markings absent. Holandric. Intestinal caeca simple. Description. Body cylindrical, small-sized, length 50.2–76.5 mm, average diameter 1.0– 2.4 mm, weight 0.17–0.22 g, segments 68–97. Body white or pale. Prostomium epilobous. First dorsal pore in 11/12. Pre-clitellar setae stouter and sparser than post-clitellar ones; setal number 34–37 in viii, 38–51 in xxx, 3–5 between two openings of copulatory pouches ventrally in xviii; setal distance aa=1.6ab, zz=1.3– 2.3zy. Clitellum closed, xiv–xvi with dorsal setae, without dorsal pores. Female single, in midventral xiv.

Two pairs of spermathecal pores in ventrolateral intersegments 7/8/9; ventral distance between two spermathecal pores about 0.35× body circumference. Male pores deeply located inside copulatory pouches. The openings of copulatory pouches oval-shaped in the setal ring xviii; ventral distance between two openings about 0.35× body circumference. Genital markings totally absent.

Septa 5/6/7/8 thick, 8/9/10 absent, 10/11/12/13 thin. Oesophageal gizzard after viii. Intestinal origin at xv; caeca simple, paired in xxvii–xxiii. Last hearts in xiii. Typhlosole simple, lamelliform. Lymph glands from 27/28.

Two pairs of spermathecae in viii and ix. Ampulla large, oval-shaped; duct about ½ ampulla length. Diverticula folded, directly attached to the duct of ampulla. Spermathecal ducts without nephridia. Accessory glands present, small, mushroom-shaped, attached directly to ampulla ducts.

Holandric. Testis sacs developed, but separated in x and xi. Seminal vesicles in xi and xii. Ovaries developed in 13/14, ovisacs invisible. Prostate glands deeply lobuled, paired in xvii–xxi; duct U-shaped, ending at copulatory pouch. Accessory glands present.

DNA barcode. A partial sequence of the mitochondrial gene cytochrome oxidase subunit I (COI) was uploaded to GenBank with the accession number MN514951 View Materials .

Habitat. The new species was found only in secondary forests on mountain slopes with very thin litter layer.

Etymology. The epithet “ houlletoides ” is used to emphasise its similarity to Metaphire houlleti ( Perrier, 1872) .

Remarks. The new species is particularly similar to Metaphire houlleti in the following characters: epilobous prostomium, presence of copulatory pouches, absence of genital markings, but presence of accessory glands in spermathecal region, holandric, simple intestinal caeca. However, the new species differs from M. houlleti in having two pairs of spermathecal pores in 7/8/9 (vs. three pairs in 6/7/8/9), smaller size (52–76.5 mm in length, 1–2.4 mm diameter vs. 82–193 mm in length, 3.3–5.4 mm diameter).

Metaphire houlletoides , new species, is assigned to the Metaphire insulata group characterised by having two pairs of spermathecal pores in 7/8/9, ducts of accessory glands ending inside copulatory pouches, being holandric, and having simple caeca ( Sims & Easton, 1972). This group consists

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19.6 22.2

GenBank

) 6 1.2 % 17.2 % % 17.2 % 21.3 % %

from (– 0.3 – 16.5 – 16.3 – 21.1 20 20.8 obtained 5) % 21.4 % 21 – % 22.6 % 20.9 % 22.4 23.3 % % 23.8

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*:

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. (15.3 21.1 – 22.1 – 18.6 – 20.4 21.1 21.9

MEGA

) 3 % % 19.5 % 15.4 20.3 % 14.8 % % % %

by (18.3 – – – – 18 21.1 19.2 calculated % 15.9 % 15.2 % 20.1 14.2 %

species 2) (

% 14.7 % 21.3 – 17.7 19.7 18.2 17.7 – 19 – 19.2 16.4 – 17.0 % 17.9 % 22.1 % 20.1 Metaphire 1) % % % 21 % – % 21.1 21.5 % % 19.0 % % % among (19.4 18 19.7 18.5 – 19.9 – 21.2 – 18.5 19.2 20.8 23.2 gene

COI 1

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) (3 (4)

of

the

species) 2 (species species * () 11

.

P

2

K

distance

2

Table

Species

new

bariaensis .

,

M M haui new.

species

,

new

M songbeensis .

,

M. houlletoides

new, *

houlleti

) 5

M. (*. 6 ( M bahli )

* 7)

M. peguana

(*

anomala

8 (

M

)

.

*

M californica .

(9) * (

guillelmi

10

. M

) aspergillus

Amynthas

of two species, M. insulata ( Gates, 1930) and M. leonoris ( Chen, 1946) . The new species differs from M. leonoris in the position of first dorsal pore (11/12 vs. 12/13), absence of genital markings in spermathecal region (vs. presence of genital markings). It is also distinguished from M. insulata by having the first dorsal pore in 11/12 (vs. 12/13) and the absence of genital markings in the spermathecal region (vs. presence of genital markings). Metaphire houlletoides , new species, is smaller than M. insulata and M. leonoris (52–76.5 mm vs. 79 mm and 125 mm in length; 1–2.4 mm vs. 5 mm and 6 mm in diameter, respectively). It is less segmented than M. leonoris (68–97 vs. 148 segments), but more segmented than M. insulata (68–97 vs. 67 segments).

Genetic distance. The K2P distance among Metaphire species is variable and relatively high, ranging from 14.2% to 23.3% (Table 2). The genetic distance between the outgroup ( Amynthas aspergillus ) and Metaphire species is also very high, ranging from 19.2% to 23.8%. The mean K2P distance among all examined species is 17.7%. The genetic K2P distance between each new species and other Metaphire species varies from 14.7 to 22.4%. It is 18–21.5% (20% in average) for M. bariaensis , new species; 14.7–22.1% (18.1% in average) for M. haui , new species; 15.3–22.4% (18.8% in average) for M. houlletoides , new species; and 14.2–21.1% (17.3% in average) for M. songbeensis , new species.

Compared to the COI intergeneric K2P distances calculated by Aspe & James (2018), the distance for Metaphire (14.2–22.3%) is somewhat similar to that for Amynthas (15.2–22.9%), but slightly lower than that for Pithemera (17.1–25.4%) and Polypheretima (16.2–23.8%). However, the divergence rate for the genus Pheretima (8.9–22.9%) is more widely variable than for the genus Metaphire (14.2–22.3%).

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