An integrative approach to characterize cryptic species in the Thoracostoma trachygaster Hope, 1967 complex (Nematoda: Leptosomatidae) Author Oliveira, Daniel Apolônio Silva De Author Decraemer, Wilfrida Author Holovachov, Oleksander Author Burr, Jay Author Ley, Irma Tandingan De Author Ley, Paul De Author Moens, Tom Author Derycke, Sofie text Zoological Journal of the Linnean Society 2012 2012-01-17 164 1 18 35 http://dx.doi.org/10.1111/j.1096-3642.2011.00758.x journal article 10.1111/j.1096-3642.2011.00758.x 0024-4082 5406191 THORACOSTOMA IGNIFERUM SP. NOV. (CLADE III) ( FIG. 9A–D, TABLE 6) Diagnosis: Thoracostoma igniferum sp. nov. closely resembles T. trachygaster and T. fatimae sp. nov. but can be distinguished from both by the irregular posterior edge of the cephalic capsule and the two internal subdorsal tropis-like projections in the wall of the cephalic capsule (only visible in crosssection). DNA sequences of the mitochondrial COI gene and the nuclear ITS and D2D3 regions differ from those of T. trachygaster in 10.9–13.3, 5.2– 5.5, and 1.0–1.1%, respectively, and from those of T. fatimae in 9.0–10.9, 6.7–6.9, and 0.8–1.0%, respectively. Etymology: The name refers to the Latin word ‘ignis’, which means fire. It refers to the irregular undulations in the posterior edge of the cephalic capsule, which resemble flames. Specimens: Eleven ( eight males , three females ) Type material: Holotype 2D24C10 (male). Paratypes 2D12C10 (female), 3D18C10 and 5D12C10 (males), and the holotype deposited in the Royal Belgian Table 6. Morphometric data of Thoracostoma igniferum sp. nov. individuals (in Mm)

2D24C10	2D12C10	3D12C10	5D12C10	6D12C10	1D13C10	3D13C10	3D18C10	1D24C10	5D24C10	2D25C10
Character	(m)	(f)	(m)	(m)	(f)	(m)	(f)	(m)	(m)	(m)	(m)	Min.	Max.	Mean	SD
Nematode length	4907	5652	5615	5242	5502	5890	5350	5241	4966	4093	5312	4093	5890	5286	493
Pharynx length	978	1144	1030	996	1064	1063	1031	1048	1072	957	973	957	1144	1038	54
Nerve ring distance	310	355	301	338	335	329	326	316	357	354	302	301	357	331	20
anterior end
Eyespot distance	58	80	77	72	72	73	77	68	82	84	62	62	84	75	7
anterior end
Pharynx	139	157	143	146	166	132	163	133	133	135	154	132	166	146	13
mbd	155	172	146	152	203	155	163	156	145	139	166	139	203	160	19
abd	93	98	120	98	104	93	87	116	87	87	109	87	120	100	12
Tail length	62	89	90	72	74	87	85	85	78	85	75	72	90	82	7
Amphid length	8	7	9	8	9	10	9	9	9	8	11	7	11	9	1
Amphid aperture	6	7	8	8	8	7	6	7	7	6	8	6	8	7	1
Amphid aperture distance	13	15	18	15	16	18	16	17	18	17	19	15	19	17	1
to anterior end
Capsule	49	52	53	53	56	50	52	50	46	47	51	46	56	51	3
Cephalic capsule width	42	47	43	46	47	41	46	42	42	42	41	41	47	44	2
posterior edge
Cephalic capsule width	21	21	26	26	24	27	26	25	24	22	21	21	27	24	2
anterior edge
Cephalic capsule length	25	31	27	29	29	27	25	27	26	25	25	25	31	27	2
Tropis length	10	9	12	12	12	16	13	12	12	11	10	9	16	12	2
a	32	33	39	34	27	38	33	34	34	30	32	30	29	33	27
b	5	5	5	5	5	6	5	5	5	4	5	4	5	5	9
c	80	63	62	73	74	68	63	61	63	48	71	57	65	64	74

The individuals are indicated by the voucher code. The first individual (2D24C10) is the holotype . Abbreviations: a, body length/body width; abd, anal body diameter; b, body length/pharynx length; c, body length/tail length; cbd, corresponding body diameter; f, female; m, male; Max., maximum; mbd, maximum body diameter; Min., minimum. Institute of Natural Science ( RBINS ) – Brussels , with the accession numbers RIT784 ( holotype ) and RIT785-RIT787 ( paratypes ). Three additional paratypes (6D12C10, 3D13C10, and 5D24C10) have been deposited in the Zoology Museum of Ghent University , under the numbers UGMD104120 – UGMD104122 . DNA material of these seven specimens is available in the Zoology Museum of Ghent University , under the numbers UGMD125007 – UGMD125013 . DNA sequences of specimen 3D13C10 are available in GenBank under the accession numbers FR853134 ( COI ), FR853144 ( ITS ), FR853143 (D2D3). Description: Body long, cylindrical, and ventrally curved; clearly anteriorly tapered in anterior neck region. Body cuticle smooth except for fine striations in head region and appearing wrinkled (rugose) in posterior precloacal region in male. Eyespot, laterally in anterior neck region conspicuous. Lip region divided into six lips; anterior sensilla arranged in an anterior crown of six inner labial papilla and a second crown of six outer labial and four cephalic setae (2–4 Mm long). Cervical setae arranged in six rows. Cephalic capsule well developed, anteriorly with slightly marked lobes and a clear ventral tropis projecting anteriorly. Posterior edge of the cephalic capsule with irregular undulations, more or less attenuated and divided into six lobes by narrow incisions, ending anteriorly in circular fenestrae showing slight variation in shape and leaving space for innervations of anterior sensilla and amphids. In crosssection, two short, pointed subdorsal tropis-like projections in the internal wall of the cephalic capsule visible at level of dorsal tooth. Amphidial fovea shieldshaped to circular, never completely surrounded by the cephalic capsule. Buccal cavity with a short blunt dorsal tooth. Pharynx without bulb, surrounded by nerve ring at about one third of the total pharynx length from anterior end. Cardia with triangular shape, projecting to the lumen of the intestine. Three caudal glands extending anteriorly beyond rectum. Males: Ventral surface at cloaca level with very minute protuberances until about the most anterior subventral setiform copulatory supplements. The ventromedian copulatory supplement is cyathiform and winged. Pair of curved spicules with the median portion more dilated. Gubernaculum with duplicated apophysis and the crura with membrane embracing the spicule. Gonads diorchic with opposed testes. Females: Vagina at 62% of the body. Intracuticular granules surrounding the transverse vagina present. Gonads amphidelphic with reflexed ovaries. Type locality: Specimens collected from stranded holdfasts of Macrocystis sp. in Ventura Beach , California , USA . Remark: The juveniles of both species can be easily confused with juveniles and adults of another common co-occurring nematode species Thoracostoma microlobatum (Allgén, 1947) . It is because of the fact that the cephalic capsule has several perforations in the juvenile, that tend to fuse or disappear along the development. In T. microlobatum those perforations persist until the adulthood. Hence, identifying the species based on juveniles may cause misidentifications.